I don’t think it’s going to replace derailleur systems, at least not until there are more innovations in materials and engineering design. And while the engineering and materials challenges are significant, I think the real challenge is going to be convincing frame manufacturers to invest in the currently unproven design...
I think it’s a “solar roadways” sized fraud. It will attract funds because it looks so glamorous, like the Crown Jewels of drivetrains. It is front-and-square at bike shows as a lure for the journalists. They use every marketing trick in the book. Lately they have even been selling the concept on the aerodynamics. Like yeah, we are concerned about the surface area of our derailleur. My prediction is that the “investors” (if there are any, $1m is a conveniently round number) will lose their money. They are crowd funding now. The end product is 2 to 3 years away and always will be. Lol. Broker’s recommendation: avoid.
Not hep on it. Looks flashy but weak. CEOs letter said the same. I run a machine shop & ride Road & FAT bikes. My Road are chain & 10 speed (ubiquitous & flexible) + a Specialized Langster Fixed Gear (unbreakable & efficient). The Belt drive running an IGH is a 'dream item' in my Future + I believe the way forward for increased drivetrain reliability. I'm SUPER curious about Shimanos 13 Speed Gearbox development - what have you heard of late ? PS I know Rolloff & Pinion are FAB but they're $$$ still & Shimano seems to have all the right factors to bring Gearbox Bikes to the FOREFRONT of the marketplace.
when building solar race cars, our numbers were 93% for chain and 86% for shaft. that was 800 lbs at 1100 watts. which really adds up on a 300 mile race.
It's long been known that chain drives were more efficient - I remember reading through a book on the history of the Morgan Car company where they were saying the same thing about their Cyclecars (2 wheels at the front and one at the back- with a chain drive ) in the early 1900s What shaft drives bring are reliability. When I worked as a MC courier I'd generally get through a chain a sprocket set every 2 months (10k) - when I switched to a shaft drive bike I'd just have to change the oil in the shaft drive every few months and have the system serviced once a year. On a pedal bike you're probably going to want to optimize for power efficiency rather than high mileage reliability, so a shaft is never likely to catch on.
@@carlofasano4293 - the question is, is it really worth optimising for high mileage reliability, as opposed to optimising for power efficiency, on a pedal bike? How many riders are really doing enough miles to justify it and will want to sacrifice power efficiency to achieve it? especially considering the comparatively low cost of a replacement sprocket/cassette and chain. Shaft drives on motorbikes have always been pretty niche - mostly restricted to the big high mileage tourers from BMW and Honda and a few other corner cases - they're going to be an even smaller niche on pedal bikes.
considering bicycle manufacturers couldn't manage to get the tolerances right on pressfit BBs, it's highly unlikely they will get them right for a shaft drive system
Reminds me of a buddy who once told me cameras would max out at 8mp as the science at that time was where it was at. I told him just wait. Imagine how far science has taken us in the last 50 years and try to think forward.
@@davidstepro7486 the issue for the bike industry is cost effectiveness . Digital cameras are relatively easy to produce cheaper . Manufacturing a part like shaft drive , ensuring quality control at frame factories and producing the volume for such parts is hard for cycle manufacturers to get right . Case in point is the new cervelo with cracking head tubes , canyon with their seat posts .
2:53 - in motorcycles, chain drives typically waste 1 to 3 percent of the input energy, where shaft drives typically waste 5 to 15 percent of the input power. Bicycle shaft drives should have similar efficiencies to this.
@Bill while that is true of motorcycles, and while the power to weight ratio would be reduced due to efficiency on a bike and a motorcycle, I don't think the weight itself would be an issue with type of design on a bicycle. Assuming the shaft is made from fiberglass, carbon fiber, or the thin aluminum bike frame tubing, the weight would probably be similar to the front chain-ring parts, rear chain-ring parts, derailleur, and chain the system replaces. Definitely so if the gears are hollowed out to the minimum needed thickness and use lighter weight alloys. The system only needs to transfer between 250 and 1000 watts or so of total mechanical power continuously, so you can get away with much thinner and lighter materials than a 65+ kilowatt rated (500+ cc) motorcycle engine could.
@@joshnabours9102 you mention the power but forgot the torque, which as said in the video, is gonna be concentrated on a small area of gears, instead of whole lenght of chain that sits on a front sprocket. In motorcycles nowadays you can only get a shaft having like +1200cc engine (VFR1200, BMW K1600, FJR1300), with few exceptions, so there's a lot of torque and power to compensate the weight and still these are only heavy touring/offroad bikes or maybe cruisers. Not a sport ones.
I used to live in an area where we had these really nasty weeds that grew these burs we called catheads, they would go straight through even those thickened puncture resistant tubes. I wound up putting stuff called green slime in them and the tyres would still pick them up and break most off again while riding but the ones that came out left tiny blobs of this green that had almost instantly sealed the punctures. There could literally be dozens of these little blobs of green and every 1 of them would have left me with a flat long before I got home. You will still lose a small amount of air and need to top them up semi regularly but at least I could go for a proper ride.
I'd recommend the Tannus Airless. They have tires with different "pressures" and different surfaces (slick/non slick/wet tires). Bit hard to get on, but ride very well and dont need swift replacement
@@GrafEnsker I must admit I'm not familiar with those tyres but, anything that can give a satisfactory ride and decent traction with low friction that DOESN'T contain air would be by far the best if you live in an area where punctures are a constant problem. I will look into them myself now too. Thanks for the information.I'm
Shaft drive bicycles have found a bit of a niche in industrial environments (e.g. navigating around large manufacturing plants or oil refineries) where efficiency isn't a major concern and the reduced risk of falls from getting pant cuffs stuck in the gears is a decent selling point.
In this environment also costs - beyond initial acquisition - for replacement parts and general maintenance are of no concern and a culture of over-provisioning guarantees availability and reliability.
That's true I have seen bicycles like that in the paper mills around here. Of course sadly and invariably they seem to want to switch over to golf carts or the industrial version of those things. Unfortunately I got a lot of Mill guys are fat and old
true, lots of large facilities have mandatory work boots and long pants, so pants getting snagged by the chain would be a concern, and my guess is even the office staff won't like getting chain grease on their suits.
When I was about six years old, my father attended a trade show and was fascinated by a shaft-driven tricycle (I believe it was called a Gear-o-cycle.) He bought one for me. It was bigger and heavier than the typical kid’s tricycle but not as big as an adult tricycle. It had a differential at the rear, but the welds that attached that differential case to the rear frame kept breaking. Eventually we gave up on it, the company that made it went out of business, and no other company ever took up a similar design.
That's usually a QC or review related issue. Proper welds are generally stronger than the base metal they're joining, so if a weld breaks, it's usually just bad welding. It's only when base metal starts to break that you should really suspect a bad design.
Out of interest what percentage of mile vs transmission failure have you had? I do around 3k miles a year not loads but only ever had slipping derailleur once around 14 years ago, only 1 broken chain around 5 years ago both were simple trail side fixes. So 2 fixable transmission issues in over 45k of miles. Had one terminal issue of a pedal sheering off and stripping the thread. Cable tied my foot to the good pedal and cycled 19 miles to the closest bike shop.
@@golddiggerdave it all depends on the terrain. I ride in the Canadian rockies and I took out two in one summer season last year. Maybe put on 500km on my mtb.
Nitpick about 5:52, the shaft needs low tolerances. High tolerance means it is more accepting of error, low tolerance means it needs to be more precise.
Most of the time I've heard "high tolerances" being used in an engineering environment it's synonymous with "tight tolerances" or "high precision". With that said it's still pretty ambiguous which is why I prefer to use "tight" or "loose" tolerances.
This problem reminds me of the bushcraft hatchet. Everyone is always trying to come up with a high-tech replacement to the traditional hatchet. The old fashioned design has its drawbacks, mainly that its quite heavy, but in all other regards it excels. It is cheap, incredibly robust, cheap and easy to repair, lasts almost indefinitely, and mother natures plain wooden handle is both durable and acts as a natural shock absorber, protecting the users wrist from fatigue. Over the years I have seen a myriad of alternative designs, all trying to make it lighter, foldable, multifunctional, or more compact. All these attempts end up causing massive negative effects, such as making it vastly weaker, causing terrible vibration in the handle, poor cutting, low durability, and almost ALL of these high tech solutions are more expensive.... and are worse. The OG wooden handled, steel head hatchet nailed the design over a millennia ago. It is just the best design hands down, and you can get a basic one from Amazon for fifteen bucks, sharpen it, put boiled linseed on the handle, and you are all set for three generations of wood cutting. Just like the traditional bicycle chain, sometimes the problem has already been solved, and attempts to improve on the solution are not worth the effort.
Maybe that’s true of the hatchet, but I don’t think it’s true of the derailleur. For one, the derailleur is part of a complex machine that hasn’t stopped being reiterated from the start. For two, the hatchet is closer to a fixed gear bike, and the derailleur closer to a proper axe or saw. And while a hatchet can’t be improved on much, there are plenty of new axes and saws that benefit from innovation.
I would not say the attempts are not worth the effort. They add to our knowledge of ways not to do it. Possible there is no better way to do it but in the hunt to improve on it you need to know what has already been tried. Quite often inventions are overturned, but only after some serious effort, and every step along the way naysayers continued to say it could not be done. Powered flight is a good example.
Another is electric cars. They have been around for a really long time but only quite recently that they started to be mass produced as a genuine competitor to ICE cars.
Some 15 years ago I went to a major bike show in the UK and was excited to ride and buy a shaft bike for leisure. When it came to my turn the bikes shaft gearbox had detached from the wheel because of loose fasteners and the show staff had not the ability to fix it.
@Giuliano Skywalker Someone who has been in automotive/mechanical engineering should be familiar with the concept of gear and shaft drives, but the tools and equipment appropriate for the drive is a different story.
What about the Alan Millyard built MTB? In very simple terms, he built an enclosed drive system, and the bike won some championship races in 2006. Very easy to mass produce from the look of it, but totally ignored. There is a few TH-cam videos of it on his channel.
I use a shaft drive bike for my commuter, and I also have a road bike with a traditional Shimano rear derailleur. Here in the Netherlands, having a shaft drive for cycling in the rain is a massive benefit. I have done virtually no maintenance on the bike in almost 5 years and I think the loss of efficiency is negligible when commuting at less than 100 watts (compared to other commuter/hybrid bikes I’ve owned in the past). I’ve also lived in dry, hilly cities and in that case, I agree that the a traditional bike would be much better.
Ah, that checks out. I was wondering what the appeal of a closed up mechanism would be. Having fixed my (literally salvaged from a junkyard) chain many times on the road, I wasn’t thinking about the average person, who isn’t going to want to have to do that under any circumstances.
that's what i was thinking, especially office workers should appreciate not getting chain grease on their trousers and it's not like you're ever going to have to fight the reduced efficiency up hill in the netherlands. also one key disadvantage of derailleur drives not mentioned in this video is that, if you have a fall or get into any other situation where something bumps the derailleur, the whole thing will never work right ever again.
They've all been tested thoroughly and the chain drive is the least friction, (something probably more important to a pushbike rider than most other applications) while belt drive was next best with shaft drive being the worst. If it was a motorbike operating in really dirty sandy type conditions I'd see the value in a shaft drive but for EVERYTHING else I'd stick with chain drive too. I've got 2 motorbikes now and seemingly only in recent years the chains somehow seem to have improved vastly compared to 15 years or so ago when I would be forever having to adjust them. On both bikes I've got I tightened them a tiny bit after about a thousand kilometers or so and keep checking but even 9,000 kilometers later on 1 it's still pretty perfect and same with the other after a few less but still not even looking like it's even changed at all since that first settling in and adjust. Admittedly 1 is only used on the road but the other gets a bit of dirt riding, not a lot these days but still, it has been in the mud and dust and is still excellent. So, I agree 100% without even watching a video once I saw that terrible high friction rear gearing arrangement in the thumbnail pic when you get to this video. I'm not going to waste my time watching the video of what looks clever(ish) but very high friction and wear and probably very easily jump teeth if you cranked hard which on a men's pushbike is a toe grinding and nutcracking nightmare, this coming from someone who grew up riding a pushbike with very second hand 3 speed hub gears that OFTEN found a sort of neutral and gave me those treatments. If it was an evil plan to stop me from breeding, it failed since I've got 3 kids lol.
@@brett7011 "Why is" what? Also, who are you asking? Any relevant reasons are already stated so if you've got a specific question, ask that specific question instead of just a general "why". EDIT: And specify WHO you're asking too.
@@lorditsprobingtime6668 interesting reply that matched my personal experiences. Part 2 for me is the bike industry is trying make a low power machine much too complex.
@@Blox117 I commute to work using a Trek Aliant 8S - it is a pedal assist ebike that allows a 68 year old man to travel 40 miles back and forth to work. :) ...the bike makes me feel like a kid again.
The city rental bikes in Antwerp, Belgium have this drivetrain. They don't feel as smooth to drive as chain-driven bikes, you really feel the cogs when pedaling. I don't expect the tolerances to be very tight on these bikes but the fact that everything is super stiff and the cogs are so close to your pedals may have something to do with it.
The chain and derailleur system is beautifully simple, reliable and easy to maintain. The troubling bit is the cable levers mechanisms which seem to break on cheap bikes.
If done correctly with crazy maintenance rotary engines are theoretically more efficient. Unfortunately they just aren't very practical or easy to maintain
I actually owned a shaft drive bicycle about a year ago. It was old, there was a lot of slop in the system and it felt like I lost a bit more power between the pedals and the wheels than on a chain drive bike, but it was quirky and fun to use! Although I wouldn't recommend it. Also worth noting that it had three gears using a shimano geared hub.
I think it would work perfectly on e bikes. The weigth and efficiency won't matter in that case. Also, i don't belive a modern, well engineered shaft drive is that much less efficient than a real-world worn and dirty chain anyways
In mountainbiking: maybe a future for shaft drive! Assuming shifting is possible and smooth it could be good for mountainbikes. It seems ressonable to think that it is more rugged than chaindrive, and if you crash or drop the bike, there is no derailleur to bend. It also will not flop around like rear derailleur.
There's no way its more rugged than a chain drive. tolerances on the mesh have to be tight and in MTB the frame and rear triangle are constantly flexing. Not to mention dirt, mud, and debris on the drive solution is just going to wreck the bearings. Just because it is stiff does not make it reliable, in fact in many cases like this stiffness makes it less reliable.
There's a reason these things haven't ever taken off. Motorcycles haven't even adopted the shaft drive. Shaft is is a solution to a problem that never existed.
@@whazzat8015 they still will be dumping a bunch of power into heating the oil around the driveshaft. When you've got to power the machine with your own meat sticks it's never going to be close. Transferring power thru 90 degrees not once but twice will always be a ball ache.
perhaps the only bike related reviewers / offers facts and data. and no pimping products to fill a you tube presentation. as always, thank you for your hard work here.
Here is my POV from a casual bike rider . I like that the chain system is easy to fix and operate . the chainless version seems to complicated and hard to fix if you were 2 miles up trail you might as well be up the creek without a paddle
But a shaft drive wouldn't fail as often as a chain. Especially in a low power application as a bicycle it should last forever. That said, chain and sprocket are much cheaper and lighter. And if you are using hub gearbox you can completely enclose the chain, reducing wear from outside dirt.
Coolest new thing Ive seen for bikes is an oval crank gear that made it easier when you were at the angle of least power and was wider where your leg was able to impart the most torque on the crank.
Actually, those eccentric chain rings were probably at the height of their popularity about 25 years ago. Even then, they weren't very common. I'm not sure but I think one problem with them might have been that they made it difficult to position the front derailleur properly as the chain would continually rise and fall with the rotation of the chain ring.
@@lyssanch3096 Well, maybe not necessarily for one-gear bicycles, but at least bicycles without a front derailleur. An eccentric chain ring wouldn't be a problem for the operation of the rear derailleur. And from what I've seen, bikes with only a rear derailleur seem to be making a comeback!
Coolest (2) bikes I ever saw were owned by two guys stopping for a break in NYC. They were hundred year old fixie shaft drives with (original) wooden rims.
To me, if the victorian/edwardian engineers choose chain over shafts then there's something in that. In them days, reliability and ease of repair was a big factor
I think the gearing needs to be at the crank, and fixed at the axle. Servicing and sealing would probably be easier. Also, the ring gear could be supported and aligned by the stronger frame, not weak spokes.
I agree. What excites me most are innovations around gearboxes like Pinion’s that happen at the crank. And, given the current technologies I like both chains and belts. I have both and they’re both great in different scenarios. I have a single speed with a chain, multiple bikes with chains and derailleurs, and a bike with a gates drive and shimano hub. They all have their place right now but an efficient, lightweight gearbox at the crank that can change gears under load seems to be the most realistic ideal. $.02
the chains advantage is that motion stays in the same direction throughout power transmission. a shaft changes three times. Each change introduces inefficiency .
although not directly comparable, there's more chain vs shaft data in the motorbike world. From memory, their numbers were 95% for chain and 80% for shaft.
There's one thing that I have to wonder about though... I assume all these tests were done with fresh sprockets and chains. But if we assume that the user is not going to maniacally change these parts as soon as there are smallest signs of wear, the efficiency will drop, and chain system will likely start wearing much faster than shaft. Maybe on average the difference is not that critical? Motorbikes also have a separate gearbox instead of a derailleur, meaning they have much less chain/sprocket wear, too
Bike chain line efficiency has been studied to death. Bike chains can reach 98% under lab conditions with certain fixed large diameter sprocket combinations, think 30T+ on both ends. In reality a fresh and properly set up 9 speed drivetrain hits between 83% and 95% depending on sprocket combination and drops from there over time. The individual factor with the highest direct impact is chain tension. Any slack in the return (ie top) of the chain greatly impacts efficiency.
Slightly off topic - back in my motorcycling days I had a motorbike with a driveshaft. On one memorable day the driveshaft snapped. I was travelling south on the A12 (in the UK) approaching the junction with the M25, maybe a mile or two away, at about 70mph. The two ends of the drive shaft then wedged together inside the casing, locking the back wheel solid. Biggest skid I ever did.
@Karl with a K Everything requires maintenance. You're just lying to make a point and it makes you sound stupid. Edit: So instead of adressing my point you try to insult me. You sir are a failure of the highest degree.
I was working in a machine shop in the mid 80's in Chico CA while going through engineering school. One of the machinist's showed me the exact concept here that he was working on. He was very excited this would revolutionize biking. I didn't think he had much of a chance of succeeding as I figured it couldn't compete with the efficiency of a chain. But here we are. I hope he profited on this some how but it's very difficult to bring a product to market, even more so before the internet. I suspect this was independently developed and he never received anything.
I like the aesthetic elegance of a shaft drive compared to a chain drive, especially when you also factor in lube mess (even was based ones), pant cuff staining, and bad weather tolerance, so I’d happily sacrifice 6% efficiency, especially for a shaft drive fixie for riding for fun or to ride something different for a change on occasion.
I thought of this years ago thinking it would be great for mountain bikes, since it can be sealed so that dirt and mud could not get into it. A bike enthusiast told me it would have more resistance.
Have been riding bicycles for 50+ years, never once did I clean a derailleur, chains will last for 10 years, while only lubing them once every 2-3 months, and all this in Dutch = rainy weather , chain and derailleur are just awesome.
Bicycles aren't the only machines that use gears or chains, the efficiency advantages of chains and belts over gears (and especially bevel gears) have been well understood for a long time.
The cost, lack of efficiency, and lack of easy fix is still prevalent today. Keep in mind the bicycle is by far the biggest mode of transportation throughout the world for almost 2 centuries. Somebody keeps trying to revive the shaft drive like somebody keeps trying to make a better rotary engine. Its not happening.
I was always interested in this idea which came out from several companies about 1910 but had disappeared within ten years. This answers my question about gear change.
So far, i've peddled hard enough to drag the chain over the gears (forced skipping), ripped the springed arm right off the bike and deformed wheels. "Cheap" and "light weight" isn't what i'm looking for in a bike anymore 😂
No one put these video essays together so well. Brilliant progression of ideas well illustrated. Specific, scientific, definitive. Clear, concise and concrete. Thorough and clearly explained. Thanks for getting down to the nitty gritty on the Driven drivetrain. We've all been wondering what the real scoop on them has been. Would like to see expanding chainrings succeed in the market. Got some ideas of my own on a cvt. Heavens. If I had a million, I think I could get something worthwhile done with it. Thanks again for your inimitable and indispensable contribution.
Myself I think it's do with the derailleur being able to be used on a wide variety of bike. I follow a guy called Allen Milliard and he made multiple amazing downhill bikesfor his son who competed that where on average around 3 secs faster than other bikes at the time. Great content very interesting, thanks for sharing.
And he did it by using a Shimano geared hub mounted inside the swing arm, with an enclosed final drive! Later versions even had single sided swing arms to speed up wheel/tyre changes. And he built it all at home in his shed! Also of note is the suspension shock/damper that Alan designed and built himself, basing his design on tank suspension!
I never even knew shaft drives were a thing for bikes. sounds like a great idea to me. I've never had a bike with a derailleur that didn't get messed up somehow after a very few uses, and wind up gettint stuck in one gear anyway. In fact it's so bad the last bike I bought was just a single gear, just like a kids, so I didn't have to deal with it.
To ignorant to figure out a bike? I wouldn't be bragging that up. I've got a 30 year old derailer that works just fine. But I know a thing or two about maintenance.
Looking at the Driven system I'd say it has a flaw you didn't mention, similar to your #3 - forces on the teeth are applied in a direction where the sprocket is weak. In a chain drive, higher tension pulls the chain into the teeth. In a shaft drive, it pushes sideways on the teeth. There's also much less distribution of force; in a fresh chain and sprocket, it can pull on multiple teeth, the Driven will only ever be one bearing pushing on one tooth. Aside from the mechanical leverage you mentioned in #3 this is why bevel gears need to be built much more heavily.
I think shaft drive would work quite well for ebikes for the same reasons they work for motorcycles; you can increase motor power to compensate for the lower efficiency. Plus with a shaft drive, you could completely encase the whole system making it much more resistant to the elements, something which ebikes do still struggle with.
eBikes actually have another point that makes then ideal for shaft drive; the motor can be mounted in alignment with the driveshaft for greater efficiency.
It's so simple - you crank a generator that shares power with a capacitor and a lithium battery. These release power to both hub motors. You also get regenerative braking and you never over-exert yourself.
Driven basically has all the right ingredients. Large chainring, fast shaft with low forces, and large casette cogs. The only real skepticism I have about it is its out of plane stiffness. though it doesn't have any of the reliability advantages over chain drives. You can't exactly imagine it working well in mud.
When possible, chains are better to use, they're more efficient, lighter, easier to repair and wear slower compared to drive gears. When you work on cars you recognise this quite fast.
@@alohatigers1199 Lmao TH-cam shadow banned your comment, even though you're pushing their views. Mechanical components are relevant to cars, even if you are concerned about the environmental impact of cars, it's a good reference point for mechanical components being used under load for extended periods of time. The environmental impact of cars is a seperate issue, not really relevant to my post.
This mechanism will wear out long before traditional chain drives. A chain drive contacts at least half the teeth thereby distributing the load. In this model the entire load is placed on one tooth at a time. It's bound to distort the teeth faster.
I hate when the "effective" and "light weight" arguments are brought up for chain drives. The VAST majority of bicycles are heavy and not used in situations where extracting that extra 3% of energy makes any difference whatsoever. Those two arguments are only valid in racing. I would argue that 99% of people who buy road or mountain bikes would save far more weight and get far more energy into the tyres if they lost weight and became fitter than they do buy fitting light weight chain drive equipment. The ACTUAL reason we keep using chains is that they are cheap, and they are cheap because we use them on everything. They are good enough for the vast majority of people. You could have a 100% effective drivetrain, and if it isn't cheap to manufacture (it won't be to start with) no one except the professionals will use it on their bicycles. If it's too expensive, not even amateur riders will use it. Similarly, if you could make a 75% efficient drivetrain that costs 1% of a chain drivetrain to make, you'd see them on bicycles everywhere tomorrow, because manufacturers would be frothing at the mouth to make money on it.
I think this is failed argument. Sure, being fitter and driving lighter bicycles would be better, but has nothing to do with drive train. “Cheap” has to do with drivetrain and is a positive feature. All in all, even if your arguments are correct, they don’t make shaft drivetrain any better, it still stays more complex, less efficient, heavier, expensive... and I would argue complexity, cost and even weight matter for any cyclist, even if the maximum efficiency wouldn’t. And that is what this video was all about. I hate when every cycling video has someone saying that in average it would make more sense for people to be more fit. I buy that argument with ceramic bearings and/or carbon wheels that are more expensive and not that efficient in comparison, but not in this case, when the cheaper drivetrain is better in about every way.
@@siffoine you might also argue that a light and efficient bike is more fun to ride, so you'll probably ride it more often, which will in the end make you fitter.
As a mountain biker, I have a chain. It works, is efficient and I can service it super easily. Not to mention relatively cheap to replace when it breaks/gets old.
I agree. I've changes my chain on my 2x11 and bought a XT chain for $33. And jokey wheels for $14. Transmission has no sound except when i change gears. Easy to install a chain with a chain breaker.
Meanwhile ive been commuting by bike for the past 10 years, between 10 and 26km a day. Ive never had to replace the chain or even had it slip off the sprocket.
Actually... If you put the drive shaft of the bike on a pivotable axis that can swing horizontally, then you can add a stack of different size gears on the back wheel. Then you would want to make the drive shaft's gear on the back end be spring loaded so it can move forward and backwards inline with the direction of the chassis, the spring action being parallel and also add a control chord you can adjust from the handlebars. Finally you will want to add a spring loaded cable to control what gear on the wheel hub is lined up the shaft. This cable would be attached to the handlebars and can even be wired through the frame. This cable is the cable that controls left and right motion along the horizontal axis (perpendicular). Now you could go through all that to make it have shiftable speeds, or you could replace the springs with motors. Or you could buy a hub motor for any bike size 20"or larger. Just a thought 🤔
Every idea starts somewhere. Its a massive engineering change. People didn't think discbrakes would Catch on. I still ride a Univega from 1992. Shimano gears are just so good. Shaft Drive is tricky, its clunky on motorbikes. Nice video. Thanks 👍
Really interesting video, I think there is a place for shaft driven bikes and it's not recreational and sportive biking : it's heavy duty low maintenance bike sharing systems. Weight and efficiency is less of a concern in bike share systems, people don't want to deal with greasy chains on their way to work or to the market.
Just using a case protecting the gears and chain will be still cheaper than using a shaft. Bevel gears are also more expensive than a simple reliable chain.
I think that rohloff+beltdrive combo becoming cheaper or efficient beltdrive CVT would be more revolutionary. With shaft drive you convert the rotation motion to another direction 2 times and you most likely have to oil on those places like with chains. Does seem overly complicated compared to beltdrive and chaindrive that doesnt convert direction of rotation movement.
I think the bike market needs some more alternatives for gear boxes. Because rohloff and pinion are just way too expensive to consider and most other options just don't have enough gear ratio. Right now the only gearbox i know that could be considered a solid value with enough gear ratio to be used on an allround (commuting/touring) bike is the alfine11.
@@jimihenrik11 I agree. Having said so, I have a Rohloff/chain combination on my about 40 kg 2-wheel cargo bicycle with the gear ratios optimized for hilly terrain. Even though I live in The Netherlands where it is mostly flat.
Love my shaft drive bicycle. I use it for exercise not racing. With prior chain bike, I hated getting pants caught in the chain, grease on myself or my pants. I also had the chain come off while riding once, which was a pain. The shaft drive solved all those problems and runs a lot smoother. I can also change gears while pedaling, which you can't do with chain/derailers.
What's that last point? "I can also change gears while pedaling, which you can't do with chain/derailers." I'm pretty sure derailleurs can't change gears _unless_ you're pedaling. I'm right with you on everything else though. I especially like how shaft drive bikes don't need anything to be oiled or re-greased constantly, they can sit in storage for half the year when you can't ride and be taken right back for a ride without having to do any maintenance and it doesn't change how they ride at all. I used to ride bikes with chains and hated how if they sat for even a few weeks without being ridden the chain had to be cleaned and oiled or it would feel like I was towing a bus.
@@GremlinSciences Maybe it was the derailleur I used to have, but you couldn't apply any drive pressure when changing gears. With my shaft drive, I can be peddling with pressure and change gears. Might not be best for longevity but so far no problems in the 6 years I've had it.
Nope. With chains engagement is also limited to 1-2 thin teeth. Gears drives have much stronger (and wider) teeths, allowing smaller gears to trasmit the same torque.
As an engineer I see a lot of unnecessary drag built into the two 90° angles the torque needs to transfer through. That's the advantage of the chain drive, its all one linear motion. Much less inherent mechanical drag.
@@awellner3285 There's also mid-mount motors usually found with conversion kits, provided the bike has a spot to install the battery and electronic compartments, which changes the bike mass balance. Though a chain bike and trousers/ dress pants for work typically don't play nice. If transmission driveshaft ebikes convince commuters to use their cars less and shift more into the electrical grid, I would not mind. So long as people BOTHERED to know that Class 3 Ebikes and electric motorbikes are legally different classifications, and I am not too pleased with bikers not following road rules, which I have personally observed everytime I commute on foot. The car always beats the biker in the weight class, and bikers think a bike helmet is sufficient protection.
You give all the percent efficiency comparing a circa 1900 early shaft drive bicycle test, then include some imagined increase in efficiency in derrailier chain drive just for 100 years of manufacturing production. Chain technology may have improved but new expensive sealed, bushed and self-lubricated chains are not miniaturized for use on bicycles. Then you add on top the improvement in chain oil lubrication to come to a final difference. Fair enough. But using the same logic, what about the known 100 years development and closer tolerances in gear design and accurate mass manufacture including CNC production? Then add the availability of many modern specialist low-friction surface coatings that can easily be applied to gears. Then likewise the new ranges of special high-pressure oils for gear lubrication? Then the improvement in mass manufactured self-lubricating ball and roller bearings that would now be used to maintain perfect shaft-drive gear tolerances. Take the perfect situation of a clean fully lubricated bicycle chain drive starting out. The moment the bicycle goes through a cloud of dust or mud we now have grinding-paste lubrication instead. The chain immediately starts drying out and wearing away. As there are only steel-rollers on steel-pins the chain is wearing away without continuous total-loss lubrication, so as the chain "stretches" with wear this only gets worse because the fit of the chain to the sprokets quickly deteriates in efficiency and exponentially increases wear on the sprockets as well. As wear is a sign of wasted energy then this says bicycle chains suffer a high AVERAGE rate of inefficency over their small lifetime. But regular lubricated gears can be maintenance-free for many 10’s of times the lifetime of chains, remain 100% grit-free, and therefore in reality may only suffer a slightly less AVERAGE efficiency than chains or NONE at all. Like almost ALL modern products the real reasons bicycles are not made with gears is 1) the initial cost, but more importantly 2) the chain system is the only important part left on the modern bicycle that requires expensive regular replacement, and 3) therefore provides the best parts sales income for manufacturers AND 4) is the most important cause of bicycle deteriation and therefore new bicycle sales.
@@leeroyjenkins0 The shaft is very unlikely to need replacement within your lifetime. The was a series of motorbikes with shaft drive put into military service during WW2 for their improved reliability in adverse environments such as the sandy dunes of the Sahara, and as hard as those bikes were pushed, many of those that were not destroyed or locked away in museum exhibits are still on the roads today _with their original drive shafts._ That's with the machining technology of the 1940's, we've come a long way and can now make gears that mesh more efficiently and that even self-align, we can make the housings better sealed and use better lubricants under higher pressure to minimize friction and wear. We've even reached the point where all the tools and machines needed to make your own parts are consumer items and can be purchased for relatively cheap; you don't need a specialist shop to order you a new shaft should yours ever break, you can mill one yourself at home for less than $10.
The simplicity and durability of chains, even in dirty conditions, has stood the test of time. On the other hand, the alternative systems are heavy, would fail in dirty conditions, near impossible to repair ona roadside and are simply not a viable alternative.
simplicity and durability of chains? in dirty condition? What? Chain is awful, always requires lube, frequent cleaning (unless you want to replace the whole drivetrain after a few thousand km), rear derailleur can be hit by some rock or literally ripped off, especially in mud. "the alternative systems would fail in dirty conditions" - why an interal geared hub with belt should fail in dirty condition? Dirt can't get into hub, and belt is like 10x times more durable than chain. For touring bikes belts are the best.
@@taufikabidin412 R&D was also done in gearboxes and shaft drives, that's why you can still buy them today. Shaft drives also has R&D in the motorcycle world (if you exclude automobiles), and the efficiency is even lower than bicycles shaft drives. Sometimes one design is just superior against another design.
@@ghoulbuster1 shaft drives existed for about the same amount of time. Sometimes one design is simply superior compared to another design for certain applications.
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You might have considered interviewing or researching amongst people that own and ride a shaft driven bike. I've owned a Dynamic Super 8 and currently ride an Incline branded version of the same frame, both ridden with a Shimano Nexus 8 IGH. I loved the bike from the start, which was about 5 years ago. In the second year I added an all in one front hub motor, allowing 5 minute conversion anytime, but it's been rare times that I swapped back to the stock front wheel. No wires, no sensors, I absolutely love the FHM. The motor assistance compounds the weight issue, while at the same time resolving it, and other downsides you mention. It's makes for a fantastic ride around town. In the winter I swap on my carbide studded 700c x 35 tires and enjoy immensely the traction benefits of the all wheel drive! It's really a fantastic combination, the IGH, plus FHM, plus shaft drive. There is a market for shaft driven bicycles, and I found extensive market research online indicating an upward trend, back in the first year or two I had mine. I really treasure my shaft driven bicycle. Thanks for the well produced video. I'm considering subscribing but will watch a few more videos first. Cheers!
There are quite a few ways to implement them easily, problem is that most of them still try to implement the classic look of a normal bike frame which causes problems.
I have one of the Driveshaft Brik Bikes shown in the video since 2014. I chose it as an ultra low maintenance, city commuter/allrounder that can left outside in the rain parked against a tree all year round. At the time, belt drive options weren't as common as they are now. Anyway, I still have mine after 10y and had one situation after 7y that the drive system completely locked up. Had to sent it back to the manufacturer to replace the drivetrain as it basically had run dry of lubricant. Was costly, but still a lot cheaper than a new bike. Now still running fine without any mentionable issues although I don't use it as much anymore. Nice tech, worked very good for my use case but in the a belt drive system would be my next choice.
The problem with this going forward is the best application would be road bikes but those guys are obsessed with simplicity and light weight.... so nope.
Just saying: I did my solo, with-bicycle world tour (53 jurisdictions) from 1976 to 1992 with a Schwinn LeTour/Sports Tourer 10 speed and Cannondale trailer. I am here to tell the tale. As a delicate old man, I now ride a 21-speed, dual-suspension using only one speed. I have taken notice of the BMW shaft drive.
I saw this product demoed on another video a few years ago. It looks amazing until you consider what will happen to the right-angle gear attached to the rear wheel when it's loaded-down by a 200lb human cranking on the pedals with all their strength. It would strip immediately.
You just think that because the modern concept of the strength of steel has been corrupted by Chinese products. You buy a screwdriver made in China and it bends etc etc real steel is actually much much stronger than you think, go get a 70 year old screwdriver from a junk shop and discover 'real' steel! But alas, if the bike is manufactured in China, you are probably right
I was at one of the largest bike shops in my state. The salesman kept trying to sell me a shaftdrive, telling me how great they were and almost zero maintenance. That was his first mistake since fixing, tweaking and doing the maintenance is very enjoyable to me. The other reason I didn't get one is because every shaftdrive they had were like cruiser bikes that were hideous looking, either they don't make "high-performance" shaftdrive or that shop didn't carry them. I still wouldn't of a shaftdrive just because I can see the shaft getting easily bent or broken if I land wrong or crash into a tree or rock. I never had a problem with chains except for my shoelace getting wrapped up.
3:24 how does an improvement in the quality of chains and belts affect the efficiency rating of shaft drives? Mathematically it makes no sense to me, the efficiency ratings are not a relative measurement between drive trains but a measure of input vs output. Unless you are defining efficiency in some wierd way.
He's making a comparasion, he's supposing (idk if that's true) that shaft drive efficiency didn't change since the date of the experiment although chains and belts efficiency did improve thanks to better lubricants and build quality apparently so the difference in the efficiencies of a shaft driven bike vs a chain driven one is even higher today than it was back when the experiment was made
@@matteobarsanti8139 that's not efficiency though. The efficiency of shaft drives did not change, which is what he claimed. Regardless the claim is a bit misleading because it only holds true for the case of bikes. The only reason shaft drives aren't efficient on bikes is due to the lack of rigid support necessitated by the weight restrictions. In heavy machinery shaft and gear drives are the most efficient means of mechanical power transmission and beat belts and chains with out question.
one drawback I experienced with chains is shifting gear while pedaling. you must not apply pedal power. often while attempting to relieve pressure you accidentally pedal backwards while the derailleur shifts and the chain gets loose. Another issue worth noting is about motor-assist bikes. Why is it difficult to pedal an e-bike? If the motor is disengaged, it should not interfere with the drive, at least in theory.
Youd really have to pull apart an ebike to find where that friction is coming from, my guess is it doesn't actually disconnect from the drive but the generator, would be easier to just have a switch flip that a mechanical disengagement. I don't know shit btw, just a guess
I can honestly say in all my years of riding different bikes,Ive only snapped a chain once.But modern gears are fiendishly annoying to adjust.I loved the Sturmey Archer 3 speed hub on a couple of my bikes.Easy to adjust and a drop if oil in the hub every so often!Maybe thats why Ive got a singlespeed bike today..... But I would like to try a shaft driven bike..
There's a very common problem that affects gear adjustment in a "modern" bicycle chain-drive drivetrain: _Misalignment of the rear derailleur _*_hanger._* The hanger is intentionally made with a relatively soft metal so it will bend or break before your expensive rear derailleur or frame dropouts. That way, if you're in an accident, you just need to replace your cheap hanger and your drivetrain is back in action. However, since it's made with soft metal, the hanger is easily (and frequently) bent out of alignment through normal use, making it frustratingly impossible to achieve a good alignment between the rear derailleur and the cogs in the cassette. If you remember to always check and align the hanger *before* you attempt to adjust the rear derailleur, you'll avoid most problems and it will be a breeze. A rear derailleur hanger alignment tool/gauge costs as little as US$35 from Amazon. A professional tool like you'd see in most bike shops would be a Park Tool DAG-2.2 which costs about US$84. Or, if you're patient, you can pick up a used one for even less on eBay. I recommend checking the hanger alignment every time you need to replace a chain and/or every time you begin to have shifting problems.
I recently gave away my old racer with Shimano Ultegra gears. I`m a rider not a maintenance/ fiddler type. The bike I gave away was 15 years old, had travelled countless thousands of miles. Mostly in the dry but not always. Incredibly, those two little wheels at the back, which must have spun round a billion times were still just fine. I wish everything was so well made.
Very interesting. Sounds like a very tall ask to beat chain drive. Reminds me of my experience with tubeless tyres. While with an optimum set up it was theoretically more efficient (even this isn't true here yet!) the downsides in achieving a good seal, especially at the road side made it a non-starters. It seems like for bikes there are a lot of downsides in performance and interchangeability. Seems like its only good for lower performance and safer no maintenance bikes. Children's bikes?
Sounds like a tall ask mostly because he's comparing an 1800's shaft-driven bike in unknown conditions to a 21st century derailleur bike that's perfectly maintained under lab conditions. Shaft-driven bikes have come a long way in the past century, they've even come a long way since the Allied military used them back in WW2. Shaft-drive is still less efficient than chain-drive, but not nearly as much as this video lets on, and are actually conditionally more efficient than chains and belts. Modern, high-end no-frills shafts (no fancy gearbox) can get 97% efficient power delivery _in all conditions and with minimal maintenance,_ while a similar chain-drive can expect 99% efficiency only under ideal conditions and can drop as low as 80% if you don't remember to clean and oil your chain after a muddy or dusty ride. Also, I'd like to point out that he tried to make it seem like a stiffer frame would only benefit shaft-drive when that stiffer frame also benefits chains and belts just as much, and the area where the stiffness is needed doesn't actually effect ride quality. The stiffness is only needed to make sure the shaft stays in alignment and the gears remain correctly meshed, that same stiffness also keeps chains and belts aligned so they don't skip or jam, and keeps the rear wheel pointed in the correct direction so you aren't riding cock-eyed.
As a mechanic i have to say belt drives arent as maintenance free as they are said to be, yes they dont (really) need a lube BUT if not maintained to the correct tension they WILL eat or grind themselfs to destruction and wont last more then 6k km's....
I dont think chain drives are going to see huge jumps from where they are already either .... at least shaft drives opens up new horizons... thats how man progresses
Chain drives are already lighter, less complex, and 99% efficient on certain configurations, hard to improve upon that. Heavier, less efficient systems have room to grow. As a consumer, i just buy the best that i can for my money and for my usage, and currently that's chain drive with derailleur.
Because the friction is enormous and engaging only 1-2 teeths isn't exactly strong point of any transmission, not to mention extremely high torque transmission like bicycle has.
@@DMSProduktions I will allow you to call it how do you choose, English isn't my first, not even my second language. The fact remains, the bevel gear has much larger working surface compared to this engineering nightmare...
From an engineer: The Driven Drivetrain is packed with design elements that necessitate a redesign, high complexity or crazy materials to work. So the possibilities I see are: 1. It gets redesigned until the actual selling point is lost. 2. The problems caused by the design intent lead to a very complex product, with a lot of moving parts, therefore low efficiency/high cost/low reliability. 3. Alternatively they try to solve those issues with the amazing tools of material science, so new and untested materials, and parts that are very expensive. Really sorry, but the design looks a bit like an Indigogo scam. Nevertheless, they might pull it off and create a revolutionary product. Can't know until you tried ^^
Right.. It was making me tired just watching this video of people peddling a bike with a Shaft Drive! Two 90 degree turns, one at the crank and one at the rear wheel, that is not good for efficiency, no matter how well it's made. With a chain drive, you have pretty much direct application of torque to the rear wheel, it's a perfect setup. Belts would be ok, but require being somewhat tight, therefore loosing efficiency. Plus some of the torque is lost in belt stretch as torque is applied.
Why use a shaft drive when you lose the fun of getting your pants leg caught in the chain. I mean come on, we all love the fashion statement of having our right pants leg tucked into our sock.
More due to application. You might be wearing loose pants biking to work in which case your point has merit. For anyone on a mountain bike I guarantee they aren't wearing khaki's.
I imagine these might also have an explosion safety factor in specific industry settings because you have no metal chain skipping over metal sprockets and it's all very contained and isolated. So in places you can't drive your car or use a conventional bike, these could potentially be handy?
I was planning on building a shaft bike from scratch. My idea was that a BMZ trick bike shouldn't have an exposed chain and gears due to the grinding and constant impacts. I'm tired of breaking the front chain ring so i thought a shaft drive would keep it all inside. It's perfect for BMX because it's just one gear and the frames are typically stiff steel frames anyway. I was going to use a carbon fiber shaft and carbon wheels to make up the weight difference and to add strength to the shaft. So far my major hurtles are the difficulty of tig welding. It's freaken hard. And now it's harder because i now know that I'm not original.
Almost no one is "original". Keep going. Sometimes a thing is worth doing simply for the satisfaction of doing it and learning along the way. In the end you'll still have a super cool bike, and have built it yourself!
Shaft drive bikes were built almost 200 years ago. It's almost impossible to think of any new idea for bicycles. Seriously, the USA originally had one patent office just for bicycles and one for EVERYTHING else. But you might be the one to crack the case.
That new system is a much more efficient method of switching between gearing ratios, but the only problem is that it is too easy for it to get clogged up because the ratio cog array attached to the rear cycle wheel is unprotected from crud from the riding surface. It might work well on a specially designed recumbent bike though.
@Alfred Wedmore you can use a belt with the internal gear box. That's really low maintenance. Only downside is that you need a frame that can "open up" to put the belt on. Might make the frame a bit less stiff.
Check out the ROKON two wheel drive motorcycle, it has a shaft system with gearing to drive the front wheel. Originally built as a utility motorcycle for people who work in forestry, and for inspectors on utility lines.
With the dawn of ebikes, you also have the issue that a shaft is actually not that much more efficient than a dynamo that gives extra power to the motor, and in terms of moving parts complexity when the bike is already an ebike, the dynamo is simpler and more reliable, and allows for absurdly flexible frames (like, it becomes viable to use elastic frames for suspension)
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QUESTION: Do you think the Driven drivetrain will make the leap from cool concept to derailleur killer? 🤔🤔
seems like shaft drive with a hub gear is a better solution? both technologies tried & trusted no point reinventing the wheel
only if you want self contained though - chain isn't going anywhere
I don’t think it’s going to replace derailleur systems, at least not until there are more innovations in materials and engineering design. And while the engineering and materials challenges are significant, I think the real challenge is going to be convincing frame manufacturers to invest in the currently unproven design...
I think it’s a “solar roadways” sized fraud. It will attract funds because it looks so glamorous, like the Crown Jewels of drivetrains.
It is front-and-square at bike shows as a lure for the journalists. They use every marketing trick in the book. Lately they have even been selling the concept on the aerodynamics. Like yeah, we are concerned about the surface area of our derailleur. My prediction is that the “investors” (if there are any, $1m is a conveniently round number) will lose their money. They are crowd funding now. The end product is 2 to 3 years away and always will be. Lol. Broker’s recommendation: avoid.
Not hep on it.
Looks flashy but weak.
CEOs letter said the same.
I run a machine shop & ride Road & FAT bikes.
My Road are chain & 10 speed (ubiquitous & flexible) + a Specialized Langster Fixed Gear (unbreakable & efficient).
The Belt drive running an IGH is a 'dream item' in my Future + I believe the way forward for increased drivetrain reliability.
I'm SUPER curious about Shimanos 13 Speed Gearbox development - what have you heard of late ?
PS I know Rolloff & Pinion are FAB but they're $$$ still & Shimano seems to have all the right factors to bring Gearbox Bikes to the FOREFRONT of the marketplace.
when building solar race cars, our numbers were 93% for chain and 86% for shaft. that was 800 lbs at 1100 watts. which really adds up on a 300 mile race.
Interesting! Thanks for the data point. 👍🏻
It's long been known that chain drives were more efficient - I remember reading through a book on the history of the Morgan Car company where they were saying the same thing about their Cyclecars (2 wheels at the front and one at the back- with a chain drive ) in the early 1900s
What shaft drives bring are reliability.
When I worked as a MC courier I'd generally get through a chain a sprocket set every 2 months (10k) - when I switched to a shaft drive bike I'd just have to change the oil in the shaft drive every few months and have the system serviced once a year.
On a pedal bike you're probably going to want to optimize for power efficiency rather than high mileage reliability, so a shaft is never likely to catch on.
What about reliability
@@bev8200 no contest on reliability: shaft wins 10 times out of 10.
As a source, just look at motorcycles applications
@@carlofasano4293 - the question is, is it really worth optimising for high mileage reliability, as opposed to optimising for power efficiency, on a pedal bike?
How many riders are really doing enough miles to justify it and will want to sacrifice power efficiency to achieve it? especially considering the comparatively low cost of a replacement sprocket/cassette and chain.
Shaft drives on motorbikes have always been pretty niche - mostly restricted to the big high mileage tourers from BMW and Honda and a few other corner cases - they're going to be an even smaller niche on pedal bikes.
considering bicycle manufacturers couldn't manage to get the tolerances right on pressfit BBs, it's highly unlikely they will get them right for a shaft drive system
Savage... but fair.
That is two very different things. Carbon is actually a difficult thing to produce to tight tolerances. Machining can be very precise
@@DaveCM some can't even machine aluminium for bb30 and pf30 .
Reminds me of a buddy who once told me cameras would max out at 8mp as the science at that time was where it was at. I told him just wait. Imagine how far science has taken us in the last 50 years and try to think forward.
@@davidstepro7486 the issue for the bike industry is cost effectiveness . Digital cameras are relatively easy to produce cheaper . Manufacturing a part like shaft drive , ensuring quality control at frame factories and producing the volume for such parts is hard for cycle manufacturers to get right . Case in point is the new cervelo with cracking head tubes , canyon with their seat posts .
2:53 - in motorcycles, chain drives typically waste 1 to 3 percent of the input energy, where shaft drives typically waste 5 to 15 percent of the input power. Bicycle shaft drives should have similar efficiencies to this.
#th-cam.com/video/8-r2U0k_zUU/w-d-xo.html
@Bill while that is true of motorcycles, and while the power to weight ratio would be reduced due to efficiency on a bike and a motorcycle, I don't think the weight itself would be an issue with type of design on a bicycle. Assuming the shaft is made from fiberglass, carbon fiber, or the thin aluminum bike frame tubing, the weight would probably be similar to the front chain-ring parts, rear chain-ring parts, derailleur, and chain the system replaces. Definitely so if the gears are hollowed out to the minimum needed thickness and use lighter weight alloys. The system only needs to transfer between 250 and 1000 watts or so of total mechanical power continuously, so you can get away with much thinner and lighter materials than a 65+ kilowatt rated (500+ cc) motorcycle engine could.
This data comes from one example. Not really scientific is it?
@@joshnabours9102 you mention the power but forgot the torque, which as said in the video, is gonna be concentrated on a small area of gears, instead of whole lenght of chain that sits on a front sprocket. In motorcycles nowadays you can only get a shaft having like +1200cc engine (VFR1200, BMW K1600, FJR1300), with few exceptions, so there's a lot of torque and power to compensate the weight and still these are only heavy touring/offroad bikes or maybe cruisers. Not a sport ones.
The thing is in bicycle you have to pedal it by yourself while in motorcycle the engine do the work
At this point, I need tires that stay inflated before I can even begin to worry about the efficiency of my drive train.
I'll make a start up that sells solid rubber tires and advertise it as not needing any pumping
I used to live in an area where we had these really nasty weeds that grew these burs we called catheads, they would go straight through even those thickened puncture resistant tubes. I wound up putting stuff called green slime in them and the tyres would still pick them up and break most off again while riding but the ones that came out left tiny blobs of this green that had almost instantly sealed the punctures. There could literally be dozens of these little blobs of green and every 1 of them would have left me with a flat long before I got home. You will still lose a small amount of air and need to top them up semi regularly but at least I could go for a proper ride.
I'd recommend the Tannus Airless. They have tires with different "pressures" and different surfaces (slick/non slick/wet tires). Bit hard to get on, but ride very well and dont need swift replacement
@@GrafEnsker I must admit I'm not familiar with those tyres but, anything that can give a satisfactory ride and decent traction with low friction that DOESN'T contain air would be by far the best if you live in an area where punctures are a constant problem. I will look into them myself now too. Thanks for the information.I'm
Or rims that never go out of true.
Shaft drive bicycles have found a bit of a niche in industrial environments (e.g. navigating around large manufacturing plants or oil refineries) where efficiency isn't a major concern and the reduced risk of falls from getting pant cuffs stuck in the gears is a decent selling point.
In this environment also costs - beyond initial acquisition - for replacement parts and general maintenance are of no concern and a culture of over-provisioning guarantees availability and reliability.
That's true I have seen bicycles like that in the paper mills around here. Of course sadly and invariably they seem to want to switch over to golf carts or the industrial version of those things. Unfortunately I got a lot of Mill guys are fat and old
I've lost count of how many pant cuffs I've ripped on my bike!
true, lots of large facilities have mandatory work boots and long pants, so pants getting snagged by the chain would be a concern, and my guess is even the office staff won't like getting chain grease on their suits.
They seem to be common in bikeshare systems for the same reason.
When I was about six years old, my father attended a trade show and was fascinated by a shaft-driven tricycle (I believe it was called a Gear-o-cycle.) He bought one for me. It was bigger and heavier than the typical kid’s tricycle but not as big as an adult tricycle. It had a differential at the rear, but the welds that attached that differential case to the rear frame kept breaking. Eventually we gave up on it, the company that made it went out of business, and no other company ever took up a similar design.
That's usually a QC or review related issue. Proper welds are generally stronger than the base metal they're joining, so if a weld breaks, it's usually just bad welding. It's only when base metal starts to break that you should really suspect a bad design.
I like chain-driven systems, but for mountain biking, the derailleur is so vulnerable to impacts. I think there's room for improvement.
Systems like the pinion gearbox paired with a gates belt are probably a better solution than a shaft drive.
Out of interest what percentage of mile vs transmission failure have you had? I do around 3k miles a year not loads but only ever had slipping derailleur once around 14 years ago, only 1 broken chain around 5 years ago both were simple trail side fixes. So 2 fixable transmission issues in over 45k of miles. Had one terminal issue of a pedal sheering off and stripping the thread. Cable tied my foot to the good pedal and cycled 19 miles to the closest bike shop.
Simple to have a guard included with the bike but that would cost $5.00 to the manufacturers... 🤣
@@golddiggerdave it all depends on the terrain. I ride in the Canadian rockies and I took out two in one summer season last year. Maybe put on 500km on my mtb.
Or if you have a little shit for a sibling that likes crashing into it
Nitpick about 5:52, the shaft needs low tolerances. High tolerance means it is more accepting of error, low tolerance means it needs to be more precise.
Was about to say the same!
@@Samonitari Ditto. I always use the unambiguous terms tight or close tolerances.
He kinda mixed high precision and low tolerances I guess.
Most of the time I've heard "high tolerances" being used in an engineering environment it's synonymous with "tight tolerances" or "high precision". With that said it's still pretty ambiguous which is why I prefer to use "tight" or "loose" tolerances.
@Ralph Macchiato kinda the whole topic here actually. Nice pun.
This problem reminds me of the bushcraft hatchet.
Everyone is always trying to come up with a high-tech replacement to the traditional hatchet. The old fashioned design has its drawbacks, mainly that its quite heavy, but in all other regards it excels. It is cheap, incredibly robust, cheap and easy to repair, lasts almost indefinitely, and mother natures plain wooden handle is both durable and acts as a natural shock absorber, protecting the users wrist from fatigue.
Over the years I have seen a myriad of alternative designs, all trying to make it lighter, foldable, multifunctional, or more compact. All these attempts end up causing massive negative effects, such as making it vastly weaker, causing terrible vibration in the handle, poor cutting, low durability, and almost ALL of these high tech solutions are more expensive.... and are worse.
The OG wooden handled, steel head hatchet nailed the design over a millennia ago. It is just the best design hands down, and you can get a basic one from Amazon for fifteen bucks, sharpen it, put boiled linseed on the handle, and you are all set for three generations of wood cutting. Just like the traditional bicycle chain, sometimes the problem has already been solved, and attempts to improve on the solution are not worth the effort.
Maybe that’s true of the hatchet, but I don’t think it’s true of the derailleur. For one, the derailleur is part of a complex machine that hasn’t stopped being reiterated from the start. For two, the hatchet is closer to a fixed gear bike, and the derailleur closer to a proper axe or saw. And while a hatchet can’t be improved on much, there are plenty of new axes and saws that benefit from innovation.
I would not say the attempts are not worth the effort. They add to our knowledge of ways not to do it. Possible there is no better way to do it but in the hunt to improve on it you need to know what has already been tried. Quite often inventions are overturned, but only after some serious effort, and every step along the way naysayers continued to say it could not be done. Powered flight is a good example.
Another is electric cars. They have been around for a really long time but only quite recently that they started to be mass produced as a genuine competitor to ICE cars.
@@phuzzo1 what kind of idiot are you, Sir?
me, an intellectual: Why do chains when you can do *GIANT GEARS*
Added weight.
*Rolls along on top of the bottom bracket gear because it's so big* 😂
@@keithwittman4741 SKELETONIZED gears.
Pedal assist seems like a far better solution.
wait till your ball sack gets caught in the gear
Some 15 years ago I went to a major bike show in the UK and was excited to ride and buy a shaft bike for leisure. When it came to my turn the bikes shaft gearbox had detached from the wheel because of loose fasteners and the show staff had not the ability to fix it.
@Giuliano Skywalker what about buying the tools and having proper assitnace from the seller?
@Giuliano Skywalker
Someone who has been in automotive/mechanical engineering should be familiar with the concept of gear and shaft drives, but the tools and equipment appropriate for the drive is a different story.
What about the Alan Millyard built MTB? In very simple terms, he built an enclosed drive system, and the bike won some championship races in 2006. Very easy to mass produce from the look of it, but totally ignored. There is a few TH-cam videos of it on his channel.
@@jerzywoking1699 Yes I saw that video, sealed drivetrain and gearbox. Amazing bike he built for his son to race.
@@brandywell44 here is the link of the MTB Alan built th-cam.com/video/iUak9sqJmnM/w-d-xo.html
I use a shaft drive bike for my commuter, and I also have a road bike with a traditional Shimano rear derailleur. Here in the Netherlands, having a shaft drive for cycling in the rain is a massive benefit. I have done virtually no maintenance on the bike in almost 5 years and I think the loss of efficiency is negligible when commuting at less than 100 watts (compared to other commuter/hybrid bikes I’ve owned in the past). I’ve also lived in dry, hilly cities and in that case, I agree that the a traditional bike would be much better.
I use closed Shimano Nexus 7speed. And the chain runs inside a cover. 4 salty rainy dirty winters and the chain looks like brand new 🙏
Ah, that checks out. I was wondering what the appeal of a closed up mechanism would be. Having fixed my (literally salvaged from a junkyard) chain many times on the road, I wasn’t thinking about the average person, who isn’t going to want to have to do that under any circumstances.
that's what i was thinking, especially office workers should appreciate not getting chain grease on their trousers and it's not like you're ever going to have to fight the reduced efficiency up hill in the netherlands.
also one key disadvantage of derailleur drives not mentioned in this video is that, if you have a fall or get into any other situation where something bumps the derailleur, the whole thing will never work right ever again.
Didn't know they made these bikes
As someone who has replaced driveshafts and chains on machines for a living, I'll take a chain over a shaft any day.
They've all been tested thoroughly and the chain drive is the least friction, (something probably more important to a pushbike rider than most other applications) while belt drive was next best with shaft drive being the worst. If it was a motorbike operating in really dirty sandy type conditions I'd see the value in a shaft drive but for EVERYTHING else I'd stick with chain drive too. I've got 2 motorbikes now and seemingly only in recent years the chains somehow seem to have improved vastly compared to 15 years or so ago when I would be forever having to adjust them. On both bikes I've got I tightened them a tiny bit after about a thousand kilometers or so and keep checking but even 9,000 kilometers later on 1 it's still pretty perfect and same with the other after a few less but still not even looking like it's even changed at all since that first settling in and adjust. Admittedly 1 is only used on the road but the other gets a bit of dirt riding, not a lot these days but still, it has been in the mud and dust and is still excellent.
So, I agree 100% without even watching a video once I saw that terrible high friction rear gearing arrangement in the thumbnail pic when you get to this video. I'm not going to waste my time watching the video of what looks clever(ish) but very high friction and wear and probably very easily jump teeth if you cranked hard which on a men's pushbike is a toe grinding and nutcracking nightmare, this coming from someone who grew up riding a pushbike with very second hand 3 speed hub gears that OFTEN found a sort of neutral and gave me those treatments. If it was an evil plan to stop me from breeding, it failed since I've got 3 kids lol.
Why is that?
@@brett7011 "Why is" what? Also, who are you asking? Any relevant reasons are already stated so if you've got a specific question, ask that specific question instead of just a general "why".
EDIT: And specify WHO you're asking too.
@@lorditsprobingtime6668 interesting reply that matched my personal experiences. Part 2 for me is the bike industry is trying make a low power machine much too complex.
@@lorditsprobingtime6668
.95
Fpfpj
Whether it be driveshaft, belt or chain - I prefer pedaling to work, rather than walking to work.
i prefer electric motors to pedaling. no sweat and no effort
@@Blox117 I commute to work using a Trek Aliant 8S - it is a pedal assist ebike that allows a 68 year old man to travel 40 miles back and forth to work. :) ...the bike makes me feel like a kid again.
@@kevingary7018 pedal assist sucks, throttle all the way
@@Blox117 Lol, change the input power supply would help that. Plus, bigger output motor.
No battery for me no motor or engine pedal power till the end
The city rental bikes in Antwerp, Belgium have this drivetrain. They don't feel as smooth to drive as chain-driven bikes, you really feel the cogs when pedaling. I don't expect the tolerances to be very tight on these bikes but the fact that everything is super stiff and the cogs are so close to your pedals may have something to do with it.
The shaft drive is like the rotary engine of the bicycle world
"Wow that's a neat idea, too bad it's worse"
@@thebirchwoodtree sad to admit but that's well said
The chain and derailleur system is beautifully simple, reliable and easy to maintain. The troubling bit is the cable levers mechanisms which seem to break on cheap bikes.
Sort of the opposite in many ways though. Rotaries are lighter, less reliable, more compact. Like shaft drives though they are less efficient.
If done correctly with crazy maintenance rotary engines are theoretically more efficient. Unfortunately they just aren't very practical or easy to maintain
I actually owned a shaft drive bicycle about a year ago. It was old, there was a lot of slop in the system and it felt like I lost a bit more power between the pedals and the wheels than on a chain drive bike, but it was quirky and fun to use! Although I wouldn't recommend it. Also worth noting that it had three gears using a shimano geared hub.
I think it would work perfectly on e bikes. The weigth and efficiency won't matter in that case. Also, i don't belive a modern, well engineered shaft drive is that much less efficient than a real-world worn and dirty chain anyways
In mountainbiking: maybe a future for shaft drive!
Assuming shifting is possible and smooth it could be good for mountainbikes. It seems ressonable to think that it is more rugged than chaindrive, and if you crash or drop the bike, there is no derailleur to bend. It also will not flop around like rear derailleur.
Good point they also need to make it a bit lighter for better bike control so that is doesn’t feel sluggish
I might be hard to make it work with mtb suspension but nothing is impossible.
maybe for cross country. anything with rear suspension is going to be impossible.
There's no way its more rugged than a chain drive. tolerances on the mesh have to be tight and in MTB the frame and rear triangle are constantly flexing. Not to mention dirt, mud, and debris on the drive solution is just going to wreck the bearings. Just because it is stiff does not make it reliable, in fact in many cases like this stiffness makes it less reliable.
@@corporalpunishment1133 It has worked for motorcycles, with a rear swing arm, for many decades.
Perfect for those who don't care about cost, efficiency or weight .
Pedal assist seems like a far better solution.
So... hipsters?
There's a reason these things haven't ever taken off. Motorcycles haven't even adopted the shaft drive. Shaft is is a solution to a problem that never existed.
@@untrainedprofessionals2374 Had Beemers for years. took them 6o years to get it right. Triumph of engineering over design.
@@whazzat8015 they still will be dumping a bunch of power into heating the oil around the driveshaft. When you've got to power the machine with your own meat sticks it's never going to be close. Transferring power thru 90 degrees not once but twice will always be a ball ache.
Belt drives look nice, clean and efficient. I’d definitely like to try one. Shaft drives are not going to get over the hurdles. Chains are great!
Harley Davidson has been using belt drive since the 1980's.
I've been riding chain drive bicycles for almost 30 years. I got a belt drive about 6 months ago and I'll never switch back.
@@john_barnettSame here. Just got a new bike with a belt. There's no going back
perhaps the only bike related reviewers / offers facts and data. and no pimping products to fill a you tube presentation. as always, thank you for your hard work here.
Here is my POV from a casual bike rider . I like that the chain system is easy to fix and operate . the chainless version seems to complicated and hard to fix if you were 2 miles up trail you might as well be up the creek without a paddle
But a shaft drive wouldn't fail as often as a chain. Especially in a low power application as a bicycle it should last forever.
That said, chain and sprocket are much cheaper and lighter. And if you are using hub gearbox you can completely enclose the chain, reducing wear from outside dirt.
@@JCGver until you break the gear teeth and are screwed
@@mass-cp6jf chain system also have teeth which grab on chain and in my experience it much more fragile.
@@RikkaYeet not even close to the same amount of stress being added. don't just say shit you know nothing about
Coolest new thing Ive seen for bikes is an oval crank gear that made it easier when you were at the angle of least power and was wider where your leg was able to impart the most torque on the crank.
I heard those wear out the chain faster not sure if true
@@lyssanch3096 propably by a slight amount as it is tensioned a bit differently as you are pedalling
Actually, those eccentric chain rings were probably at the height of their popularity about 25 years ago. Even then, they weren't very common. I'm not sure but I think one problem with them might have been that they made it difficult to position the front derailleur properly as the chain would continually rise and fall with the rotation of the chain ring.
@@eyesuckle so its better suited for single speeds ?
@@lyssanch3096 Well, maybe not necessarily for one-gear bicycles, but at least bicycles without a front derailleur. An eccentric chain ring wouldn't be a problem for the operation of the rear derailleur. And from what I've seen, bikes with only a rear derailleur seem to be making a comeback!
I don’t even care about any of this. I now want a shaft drivetrain bike, solely because they look cooler than normal bikes. That’s the only reason.
Good luck with that philosophy
I’m thinking you’re sarcastic but I’m sure there’s a ton of other people with his mindset
Its ALWAYS about astetics.
@@Bitterstone3849 You’re damn right
@@animalanimal7939 Thanks homie
Coolest (2) bikes I ever saw were owned by two guys stopping for a break in NYC. They were hundred year old fixie shaft drives with (original) wooden rims.
Cool
coolest bike i ever seen was some crackhead who welded a bunch of 20 inch frames together untill the bike was like 18 ft high 😢
Hey, we want pictures!!
@@stevephillips8192 bump
i love crack ideas
To me, if the victorian/edwardian engineers choose chain over shafts then there's something in that. In them days, reliability and ease of repair was a big factor
Yeah they'll be selling plastic chains in a few years. If they already dont
I think the gearing needs to be at the crank, and fixed at the axle.
Servicing and sealing would probably be easier. Also, the ring gear could be supported and aligned by the stronger frame, not weak spokes.
@MikMech -- that is what I have always thought too. A Rohloff hub with a shaft drive might be the ideal city bike set-up.
I agree. What excites me most are innovations around gearboxes like Pinion’s that happen at the crank. And, given the current technologies I like both chains and belts. I have both and they’re both great in different scenarios. I have a single speed with a chain, multiple bikes with chains and derailleurs, and a bike with a gates drive and shimano hub. They all have their place right now but an efficient, lightweight gearbox at the crank that can change gears under load seems to be the most realistic ideal.
$.02
Note to self: modify Street Racing car to use chain drive and derailer.
Reliability is a factor
Buy a Fraser-Ńash car.
No point. They have transmission with a shaft drivetrain😂 derailleurs are just small size transmissions😂
the chains advantage is that motion stays in the same direction throughout power transmission. a shaft changes three times. Each change introduces inefficiency .
Added to that is the shaft is angled away from the crank-angle!
although not directly comparable, there's more chain vs shaft data in the motorbike world. From memory, their numbers were 95% for chain and 80% for shaft.
There's one thing that I have to wonder about though... I assume all these tests were done with fresh sprockets and chains. But if we assume that the user is not going to maniacally change these parts as soon as there are smallest signs of wear, the efficiency will drop, and chain system will likely start wearing much faster than shaft. Maybe on average the difference is not that critical?
Motorbikes also have a separate gearbox instead of a derailleur, meaning they have much less chain/sprocket wear, too
Bike chain line efficiency has been studied to death. Bike chains can reach 98% under lab conditions with certain fixed large diameter sprocket combinations, think 30T+ on both ends.
In reality a fresh and properly set up 9 speed drivetrain hits between 83% and 95% depending on sprocket combination and drops from there over time. The individual factor with the highest direct impact is chain tension. Any slack in the return (ie top) of the chain greatly impacts efficiency.
@N V Percent energy transferred, the higher the better. Remaining lost to noise and heat.
@N V Different parts do different things. Thus different efficiencies. Dont mix things.
Slightly off topic - back in my motorcycling days I had a motorbike with a driveshaft. On one memorable day the driveshaft snapped. I was travelling south on the A12 (in the UK) approaching the junction with the M25, maybe a mile or two away, at about 70mph. The two ends of the drive shaft then wedged together inside the casing, locking the back wheel solid. Biggest skid I ever did.
In my experience, the few shaft-driven bikes I had rided feel much heavier than normal chain-driven ones.
@Karl with a K The video stated that they are less efficient than a chain drive…
@Karl with a K "zero maintenance" is a complete lie.
@Karl with a K Everything requires maintenance. You're just lying to make a point and it makes you sound stupid.
Edit: So instead of adressing my point you try to insult me. You sir are a failure of the highest degree.
@Karl with a K you should be a shaft bike manufacturer for saying shaft are more efficient :D
I was working in a machine shop in the mid 80's in Chico CA while going through engineering school. One of the machinist's showed me the exact concept here that he was working on. He was very excited this would revolutionize biking. I didn't think he had much of a chance of succeeding as I figured it couldn't compete with the efficiency of a chain. But here we are. I hope he profited on this some how but it's very difficult to bring a product to market, even more so before the internet. I suspect this was independently developed and he never received anything.
There's also one system I've seen where it's rods pushing back and forth.
I like the aesthetic elegance of a shaft drive compared to a chain drive, especially when you also factor in lube mess (even was based ones), pant cuff staining, and bad weather tolerance, so I’d happily sacrifice 6% efficiency, especially for a shaft drive fixie for riding for fun or to ride something different for a change on occasion.
I thought of this years ago thinking it would be great for mountain bikes, since it can be sealed so that dirt and mud could not get into it.
A bike enthusiast told me it would have more resistance.
There are patents and even mass produced shaft driven bicycles going back into the late 1800's. There is a reason they never succeeded.
@@tobyvision but hey intrusive market popping up maybe?
Have been riding bicycles for 50+ years, never once did I clean a derailleur, chains will last for 10 years, while only lubing them once every 2-3 months, and all this in Dutch = rainy weather , chain and derailleur are just awesome.
that is A LOT of assumptions you make about shaft drives based
on one test from the 1980s
Bicycles aren't the only machines that use gears or chains, the efficiency advantages of chains and belts over gears (and especially bevel gears) have been well understood for a long time.
The cost, lack of efficiency, and lack of easy fix is still prevalent today. Keep in mind the bicycle is by far the biggest mode of transportation throughout the world for almost 2 centuries. Somebody keeps trying to revive the shaft drive like somebody keeps trying to make a better rotary engine. Its not happening.
I was always interested in this idea which came out from several companies about 1910 but had disappeared within ten years. This answers my question about gear change.
So far, i've peddled hard enough to drag the chain over the gears (forced skipping), ripped the springed arm right off the bike and deformed wheels.
"Cheap" and "light weight" isn't what i'm looking for in a bike anymore 😂
No one put these video essays together so well. Brilliant progression of ideas well illustrated. Specific, scientific, definitive. Clear, concise and concrete. Thorough and clearly explained. Thanks for getting down to the nitty gritty on the Driven drivetrain. We've all been wondering what the real scoop on them has been. Would like to see expanding chainrings succeed in the market. Got some ideas of my own on a cvt. Heavens. If I had a million, I think I could get something worthwhile done with it. Thanks again for your inimitable and indispensable contribution.
Thanks Stan!
Myself I think it's do with the derailleur being able to be used on a wide variety of bike. I follow a guy called Allen Milliard and he made multiple amazing downhill bikesfor his son who competed that where on average around 3 secs faster than other bikes at the time. Great content very interesting, thanks for sharing.
And he did it by using a Shimano geared hub mounted inside the swing arm, with an enclosed final drive! Later versions even had single sided swing arms to speed up wheel/tyre changes. And he built it all at home in his shed! Also of note is the suspension shock/damper that Alan designed and built himself, basing his design on tank suspension!
I never even knew shaft drives were a thing for bikes. sounds like a great idea to me. I've never had a bike with a derailleur that didn't get messed up somehow after a very few uses, and wind up gettint stuck in one gear anyway.
In fact it's so bad the last bike I bought was just a single gear, just like a kids, so I didn't have to deal with it.
You must have been buying low end bikes then
Internally geared hubs are a thing too.
Maybe next time you will take better care of your bikes.
Try adjusting the derailleur
To ignorant to figure out a bike? I wouldn't be bragging that up.
I've got a 30 year old derailer that works just fine. But I know a thing or two about maintenance.
Looking at the Driven system I'd say it has a flaw you didn't mention, similar to your #3 - forces on the teeth are applied in a direction where the sprocket is weak. In a chain drive, higher tension pulls the chain into the teeth. In a shaft drive, it pushes sideways on the teeth. There's also much less distribution of force; in a fresh chain and sprocket, it can pull on multiple teeth, the Driven will only ever be one bearing pushing on one tooth. Aside from the mechanical leverage you mentioned in #3 this is why bevel gears need to be built much more heavily.
I think shaft drive would work quite well for ebikes for the same reasons they work for motorcycles; you can increase motor power to compensate for the lower efficiency. Plus with a shaft drive, you could completely encase the whole system making it much more resistant to the elements, something which ebikes do still struggle with.
Very good points!
more power equals more battery consumption. You've just killed your range.
eBikes actually have another point that makes then ideal for shaft drive; the motor can be mounted in alignment with the driveshaft for greater efficiency.
It's so simple - you crank a generator that shares power with a capacitor and a lithium battery. These release power to both hub motors.
You also get regenerative braking and you never over-exert yourself.
Driven basically has all the right ingredients. Large chainring, fast shaft with low forces, and large casette cogs.
The only real skepticism I have about it is its out of plane stiffness.
though it doesn't have any of the reliability advantages over chain drives. You can't exactly imagine it working well in mud.
It might be easier to shield and clean.
When possible, chains are better to use, they're more efficient, lighter, easier to repair and wear slower compared to drive gears. When you work on cars you recognise this quite fast.
Ah
When you understand climate change, we don’t need cars
@@alohatigers1199 Lmao TH-cam shadow banned your comment, even though you're pushing their views. Mechanical components are relevant to cars, even if you are concerned about the environmental impact of cars, it's a good reference point for mechanical components being used under load for extended periods of time. The environmental impact of cars is a seperate issue, not really relevant to my post.
This mechanism will wear out long before traditional chain drives. A chain drive contacts at least half the teeth thereby distributing the load. In this model the entire load is placed on one tooth at a time. It's bound to distort the teeth faster.
shaft drive is a great idea. I think it'll work for those people who are putting electric motors in their bicycles. I'm seeing a lot more of them
I hate when the "effective" and "light weight" arguments are brought up for chain drives. The VAST majority of bicycles are heavy and not used in situations where extracting that extra 3% of energy makes any difference whatsoever. Those two arguments are only valid in racing. I would argue that 99% of people who buy road or mountain bikes would save far more weight and get far more energy into the tyres if they lost weight and became fitter than they do buy fitting light weight chain drive equipment.
The ACTUAL reason we keep using chains is that they are cheap, and they are cheap because we use them on everything. They are good enough for the vast majority of people. You could have a 100% effective drivetrain, and if it isn't cheap to manufacture (it won't be to start with) no one except the professionals will use it on their bicycles. If it's too expensive, not even amateur riders will use it.
Similarly, if you could make a 75% efficient drivetrain that costs 1% of a chain drivetrain to make, you'd see them on bicycles everywhere tomorrow, because manufacturers would be frothing at the mouth to make money on it.
I think this is failed argument. Sure, being fitter and driving lighter bicycles would be better, but has nothing to do with drive train. “Cheap” has to do with drivetrain and is a positive feature. All in all, even if your arguments are correct, they don’t make shaft drivetrain any better, it still stays more complex, less efficient, heavier, expensive... and I would argue complexity, cost and even weight matter for any cyclist, even if the maximum efficiency wouldn’t. And that is what this video was all about. I hate when every cycling video has someone saying that in average it would make more sense for people to be more fit. I buy that argument with ceramic bearings and/or carbon wheels that are more expensive and not that efficient in comparison, but not in this case, when the cheaper drivetrain is better in about every way.
@@siffoine you might also argue that a light and efficient bike is more fun to ride, so you'll probably ride it more often, which will in the end make you fitter.
As a mountain biker, I have a chain. It works, is efficient and I can service it super easily. Not to mention relatively cheap to replace when it breaks/gets old.
I agree. I've changes my chain on my 2x11 and bought a XT chain for $33. And jokey wheels for $14. Transmission has no sound except when i change gears. Easy to install a chain with a chain breaker.
Driveshaft bikes are already being used in citybikes in Cracow and they're way more reliable than chain bikes in other cities around here.
Meanwhile ive been commuting by bike for the past 10 years, between 10 and 26km a day. Ive never had to replace the chain or even had it slip off the sprocket.
@@awellner3285 impressive!
@@awellner3285 Must take care of that bike.
Shafts are more reliable and durable. But less efficient. I would rather choose the chain ones. For comfortable cycling.
@@awellner3285 You're lucky.
Actually... If you put the drive shaft of the bike on a pivotable axis that can swing horizontally, then you can add a stack of different size gears on the back wheel. Then you would want to make the drive shaft's gear on the back end be spring loaded so it can move forward and backwards inline with the direction of the chassis, the spring action being parallel and also add a control chord you can adjust from the handlebars. Finally you will want to add a spring loaded cable to control what gear on the wheel hub is lined up the shaft. This cable would be attached to the handlebars and can even be wired through the frame. This cable is the cable that controls left and right motion along the horizontal axis (perpendicular). Now you could go through all that to make it have shiftable speeds, or you could replace the springs with motors. Or you could buy a hub motor for any bike size 20"or larger. Just a thought 🤔
Every idea starts somewhere.
Its a massive engineering change.
People didn't think discbrakes would
Catch on. I still ride a Univega from 1992.
Shimano gears are just so good. Shaft
Drive is tricky, its clunky on motorbikes.
Nice video. Thanks 👍
Really interesting video, I think there is a place for shaft driven bikes and it's not recreational and sportive biking : it's heavy duty low maintenance bike sharing systems.
Weight and efficiency is less of a concern in bike share systems, people don't want to deal with greasy chains on their way to work or to the market.
Just using a case protecting the gears and chain will be still cheaper than using a shaft. Bevel gears are also more expensive than a simple reliable chain.
I think that rohloff+beltdrive combo becoming cheaper or efficient beltdrive CVT would be more revolutionary.
With shaft drive you convert the rotation motion to another direction 2 times and you most likely have to oil on those places like with chains. Does seem overly complicated compared to beltdrive and chaindrive that doesnt convert direction of rotation movement.
concur + as saying goes : gimmicks can be defined by amount superfluous parts
I think the bike market needs some more alternatives for gear boxes. Because rohloff and pinion are just way too expensive to consider and most other options just don't have enough gear ratio. Right now the only gearbox i know that could be considered a solid value with enough gear ratio to be used on an allround (commuting/touring) bike is the alfine11.
@@jimihenrik11
I agree.
Having said so, I have a Rohloff/chain combination on my about 40 kg 2-wheel cargo bicycle with the gear ratios optimized for hilly terrain.
Even though I live in The Netherlands where it is mostly flat.
Love my shaft drive bicycle. I use it for exercise not racing. With prior chain bike, I hated getting pants caught in the chain, grease on myself or my pants. I also had the chain come off while riding once, which was a pain. The shaft drive solved all those problems and runs a lot smoother. I can also change gears while pedaling, which you can't do with chain/derailers.
What's that last point? "I can also change gears while pedaling, which you can't do with chain/derailers." I'm pretty sure derailleurs can't change gears _unless_ you're pedaling.
I'm right with you on everything else though. I especially like how shaft drive bikes don't need anything to be oiled or re-greased constantly, they can sit in storage for half the year when you can't ride and be taken right back for a ride without having to do any maintenance and it doesn't change how they ride at all. I used to ride bikes with chains and hated how if they sat for even a few weeks without being ridden the chain had to be cleaned and oiled or it would feel like I was towing a bus.
@@GremlinSciences Maybe it was the derailleur I used to have, but you couldn't apply any drive pressure when changing gears. With my shaft drive, I can be peddling with pressure and change gears. Might not be best for longevity but so far no problems in the 6 years I've had it.
Love these super high quality videos man, awesome stuff
Much appreciated!
Chains are stronger. They engage nearly half the teeth around a gear vs a gear on gear drive that engages just 1 or 2 teeth at a time.
Pedal assist seems like a far better solution.
Nope.
With chains engagement is also limited to 1-2 thin teeth.
Gears drives have much stronger (and wider) teeths, allowing smaller gears to trasmit the same torque.
You will love chains until they get derailed when you ride your bike.
@@frostsmaker8966 actually the one thing I love about bike chains is that I can easily put them back on lol.
@@frostsmaker8966 that's an easy fix though
As an engineer I see a lot of unnecessary drag built into the two 90° angles the torque needs to transfer through.
That's the advantage of the chain drive, its all one linear motion. Much less inherent mechanical drag.
0:16 yeah, they're so common that i never heard about other mechanics
With the rise of e bikes, I think for a nice adventure ebike built for doing long distances on and off road the shaft is phenomenal.
Dont most E bikes have hub motors?
Any sort of power transmission from motor to wheel would be inefficient in comparison
@@awellner3285 There's also mid-mount motors usually found with conversion kits, provided the bike has a spot to install the battery and electronic compartments, which changes the bike mass balance.
Though a chain bike and trousers/ dress pants for work typically don't play nice.
If transmission driveshaft ebikes convince commuters to use their cars less and shift more into the electrical grid, I would not mind. So long as people BOTHERED to know that Class 3 Ebikes and electric motorbikes are legally different classifications, and I am not too pleased with bikers not following road rules, which I have personally observed everytime I commute on foot. The car always beats the biker in the weight class, and bikers think a bike helmet is sufficient protection.
@@awellner3285 hub motors are easier to fit, but they have the same disadvantages as regular singlespeed bike.
You give all the percent efficiency comparing a circa 1900 early shaft drive bicycle test, then include some imagined increase in efficiency in derrailier chain drive just for 100 years of manufacturing production. Chain technology may have improved but new expensive sealed, bushed and self-lubricated chains are not miniaturized for use on bicycles. Then you add on top the improvement in chain oil lubrication to come to a final difference.
Fair enough. But using the same logic, what about the known 100 years development and closer tolerances in gear design and accurate mass manufacture including CNC production? Then add the availability of many modern specialist low-friction surface coatings that can easily be applied to gears. Then likewise the new ranges of special high-pressure oils for gear lubrication? Then the improvement in mass manufactured self-lubricating ball and roller bearings that would now be used to maintain perfect shaft-drive gear tolerances.
Take the perfect situation of a clean fully lubricated bicycle chain drive starting out. The moment the bicycle goes through a cloud of dust or mud we now have grinding-paste lubrication instead. The chain immediately starts drying out and wearing away. As there are only steel-rollers on steel-pins the chain is wearing away without continuous total-loss lubrication, so as the chain "stretches" with wear this only gets worse because the fit of the chain to the sprokets quickly deteriates in efficiency and exponentially increases wear on the sprockets as well. As wear is a sign of wasted energy then this says bicycle chains suffer a high AVERAGE rate of inefficency over their small lifetime. But regular lubricated gears can be maintenance-free for many 10’s of times the lifetime of chains, remain 100% grit-free, and therefore in reality may only suffer a slightly less AVERAGE efficiency than chains or NONE at all.
Like almost ALL modern products the real reasons bicycles are not made with gears is 1) the initial cost, but more importantly 2) the chain system is the only important part left on the modern bicycle that requires expensive regular replacement, and 3) therefore provides the best parts sales income for manufacturers AND 4) is the most important cause of bicycle deteriation and therefore new bicycle sales.
@@leeroyjenkins0 The shaft is very unlikely to need replacement within your lifetime.
The was a series of motorbikes with shaft drive put into military service during WW2 for their improved reliability in adverse environments such as the sandy dunes of the Sahara, and as hard as those bikes were pushed, many of those that were not destroyed or locked away in museum exhibits are still on the roads today _with their original drive shafts._ That's with the machining technology of the 1940's, we've come a long way and can now make gears that mesh more efficiently and that even self-align, we can make the housings better sealed and use better lubricants under higher pressure to minimize friction and wear. We've even reached the point where all the tools and machines needed to make your own parts are consumer items and can be purchased for relatively cheap; you don't need a specialist shop to order you a new shaft should yours ever break, you can mill one yourself at home for less than $10.
Driven drivetrain seems to have all the drawbacks of a shaft system with all the drawbacks of a chain system... With no notable positives
Except smoother gear ratio changing, ...which didn't even get a mention in this video.
@@penfold7800 nuVinchi achieved that long ago, and to the perfect degree - that's CVT!
The simplicity and durability of chains, even in dirty conditions, has stood the test of time. On the other hand, the alternative systems are heavy, would fail in dirty conditions, near impossible to repair ona roadside and are simply not a viable alternative.
Because all RnD was done in chain. I dont see many chain deraileur system in cars and machines
simplicity and durability of chains? in dirty condition? What? Chain is awful, always requires lube, frequent cleaning (unless you want to replace the whole drivetrain after a few thousand km), rear derailleur can be hit by some rock or literally ripped off, especially in mud.
"the alternative systems would fail in dirty conditions" - why an interal geared hub with belt should fail in dirty condition? Dirt can't get into hub, and belt is like 10x times more durable than chain. For touring bikes belts are the best.
Chains are 200 years old, plenty of time to evolve.
Back then chains weren't so efficient.
@@taufikabidin412 R&D was also done in gearboxes and shaft drives, that's why you can still buy them today.
Shaft drives also has R&D in the motorcycle world (if you exclude automobiles), and the efficiency is even lower than bicycles shaft drives.
Sometimes one design is just superior against another design.
@@ghoulbuster1 shaft drives existed for about the same amount of time. Sometimes one design is simply superior compared to another design for certain applications.
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The traditional (chain) system, however, is the most perfect way to transform the energy for both bicycle and motorcycle.
They scale pretty poorly eg road cars
I think BMW motorcycle shaft drives prove you wrong.
Nah, chains are just a really good balance between cost, simplicity and efficiency
@@percyfaith11 Have you looked at the maintenance frequency required for that shaft drive?
@@robertheinkel6225 No, is it onerous?
I had an instructor in uni, that had built a hydraulic bike with a small custom cvt.
You might have considered interviewing or researching amongst people that own and ride a shaft driven bike. I've owned a Dynamic Super 8 and currently ride an Incline branded version of the same frame, both ridden with a Shimano Nexus 8 IGH. I loved the bike from the start, which was about 5 years ago. In the second year I added an all in one front hub motor, allowing 5 minute conversion anytime, but it's been rare times that I swapped back to the stock front wheel. No wires, no sensors, I absolutely love the FHM. The motor assistance compounds the weight issue, while at the same time resolving it, and other downsides you mention. It's makes for a fantastic ride around town. In the winter I swap on my carbide studded 700c x 35 tires and enjoy immensely the traction benefits of the all wheel drive! It's really a fantastic combination, the IGH, plus FHM, plus shaft drive. There is a market for shaft driven bicycles, and I found extensive market research online indicating an upward trend, back in the first year or two I had mine. I really treasure my shaft driven bicycle. Thanks for the well produced video. I'm considering subscribing but will watch a few more videos first. Cheers!
Also rear suspension is harder to implement
There are quite a few ways to implement them easily, problem is that most of them still try to implement the classic look of a normal bike frame which causes problems.
Motorcyclists have been doing off-road rallying with huge suspension travel for decades on shafties (especially Yamaha and BMW) - it can be done!
Not harder, but even more expensive, complex, heavy and more mechanical losses. Not worth a shot outside of some pretty specific use.
FINALLY! A bike I can ride with my pants that have loos ankles on them!
That’s what I was thinking.
Keep velcro straps on your handlebars for your pant legs
@@DeAthWaGer Exactly 👍
I have trouble with my long skirts!
Fixed that with Truvativ Hammerschmidt a decade ago.
I have one of the Driveshaft Brik Bikes shown in the video since 2014. I chose it as an ultra low maintenance, city commuter/allrounder that can left outside in the rain parked against a tree all year round.
At the time, belt drive options weren't as common as they are now.
Anyway, I still have mine after 10y and had one situation after 7y that the drive system completely locked up. Had to sent it back to the manufacturer to replace the drivetrain as it basically had run dry of lubricant. Was costly, but still a lot cheaper than a new bike.
Now still running fine without any mentionable issues although I don't use it as much anymore.
Nice tech, worked very good for my use case but in the a belt drive system would be my next choice.
The problem with this going forward is the best application would be road bikes but those guys are obsessed with simplicity and light weight.... so nope.
How is this best for road bikes?
From all I've heard, these are way slower than a derailleur. And speed is kinda what road bikes are for....
Chains have less friction and weigh much less than an axle.
I'm gonna get some of your books as I love how you dig into topics ! Great Job Alee :)
Thanks Nicolas, I appreciate that! 😊
Me too.
Just saying: I did my solo, with-bicycle world tour (53 jurisdictions) from 1976 to 1992 with a Schwinn LeTour/Sports Tourer 10 speed and Cannondale trailer. I am here to tell the tale. As a delicate old man, I now ride a 21-speed, dual-suspension using only one speed. I have taken notice of the BMW shaft drive.
I'm just waiting on photon drive with a flux capacitor. I have times to be and places to see.
On a bicycle? warp 2, at most.
I saw this product demoed on another video a few years ago. It looks amazing until you consider what will happen to the right-angle gear attached to the rear wheel when it's loaded-down by a 200lb human cranking on the pedals with all their strength. It would strip immediately.
You just think that because the modern concept of the strength of steel has been corrupted by Chinese products. You buy a screwdriver made in China and it bends etc etc
real steel is actually much much stronger than you think, go get a 70 year old screwdriver from a junk shop and discover 'real' steel!
But alas, if the bike is manufactured in China, you are probably right
@@mystikmind2005 Just stick to a conventional derailleur system, the design in this video is engineering nonsense
How do they work on motorcycles? 🏍
I was at one of the largest bike shops in my state. The salesman kept trying to sell me a shaftdrive, telling me how great they were and almost zero maintenance. That was his first mistake since fixing, tweaking and doing the maintenance is very enjoyable to me. The other reason I didn't get one is because every shaftdrive they had were like cruiser bikes that were hideous looking, either they don't make "high-performance" shaftdrive or that shop didn't carry them. I still wouldn't of a shaftdrive just because I can see the shaft getting easily bent or broken if I land wrong or crash into a tree or rock. I never had a problem with chains except for my shoelace getting wrapped up.
Can’t wait to wear flared jeans while I’m shredding without any fear at all .
3:24 how does an improvement in the quality of chains and belts affect the efficiency rating of shaft drives? Mathematically it makes no sense to me, the efficiency ratings are not a relative measurement between drive trains but a measure of input vs output. Unless you are defining efficiency in some wierd way.
He's making a comparasion, he's supposing (idk if that's true) that shaft drive efficiency didn't change since the date of the experiment although chains and belts efficiency did improve thanks to better lubricants and build quality apparently so the difference in the efficiencies of a shaft driven bike vs a chain driven one is even higher today than it was back when the experiment was made
@@matteobarsanti8139 that's not efficiency though. The efficiency of shaft drives did not change, which is what he claimed. Regardless the claim is a bit misleading because it only holds true for the case of bikes. The only reason shaft drives aren't efficient on bikes is due to the lack of rigid support necessitated by the weight restrictions. In heavy machinery shaft and gear drives are the most efficient means of mechanical power transmission and beat belts and chains with out question.
one drawback I experienced with chains is shifting gear while pedaling. you must not apply pedal power. often while attempting to relieve pressure you accidentally pedal backwards while the derailleur shifts and the chain gets loose. Another issue worth noting is about motor-assist bikes. Why is it difficult to pedal an e-bike? If the motor is disengaged, it should not interfere with the drive, at least in theory.
Youd really have to pull apart an ebike to find where that friction is coming from, my guess is it doesn't actually disconnect from the drive but the generator, would be easier to just have a switch flip that a mechanical disengagement. I don't know shit btw, just a guess
I can honestly say in all my years of riding different bikes,Ive only snapped a chain once.But modern gears are fiendishly annoying to adjust.I loved the Sturmey Archer 3 speed hub on a couple of my bikes.Easy to adjust and a drop if oil in the hub every so often!Maybe thats why Ive got a singlespeed bike today.....
But I would like to try a shaft driven bike..
There's a very common problem that affects gear adjustment in a "modern" bicycle chain-drive drivetrain: _Misalignment of the rear derailleur _*_hanger._*
The hanger is intentionally made with a relatively soft metal so it will bend or break before your expensive rear derailleur or frame dropouts. That way, if you're in an accident, you just need to replace your cheap hanger and your drivetrain is back in action. However, since it's made with soft metal, the hanger is easily (and frequently) bent out of alignment through normal use, making it frustratingly impossible to achieve a good alignment between the rear derailleur and the cogs in the cassette. If you remember to always check and align the hanger *before* you attempt to adjust the rear derailleur, you'll avoid most problems and it will be a breeze.
A rear derailleur hanger alignment tool/gauge costs as little as US$35 from Amazon. A professional tool like you'd see in most bike shops would be a Park Tool DAG-2.2 which costs about US$84. Or, if you're patient, you can pick up a used one for even less on eBay. I recommend checking the hanger alignment every time you need to replace a chain and/or every time you begin to have shifting problems.
Keep in mind that belt drives also require pinpoint tensioning and alignment, as well as spray-on silicone lubricant.
I recently gave away my old racer with Shimano Ultegra gears. I`m a rider not a maintenance/ fiddler type. The bike I gave away was 15 years old, had travelled countless thousands of miles. Mostly in the dry but not always. Incredibly, those two little wheels at the back, which must have spun round a billion times were still just fine. I wish everything was so well made.
Very interesting. Sounds like a very tall ask to beat chain drive. Reminds me of my experience with tubeless tyres. While with an optimum set up it was theoretically more efficient (even this isn't true here yet!) the downsides in achieving a good seal, especially at the road side made it a non-starters. It seems like for bikes there are a lot of downsides in performance and interchangeability. Seems like its only good for lower performance and safer no maintenance bikes. Children's bikes?
Sounds like a tall ask mostly because he's comparing an 1800's shaft-driven bike in unknown conditions to a 21st century derailleur bike that's perfectly maintained under lab conditions.
Shaft-driven bikes have come a long way in the past century, they've even come a long way since the Allied military used them back in WW2. Shaft-drive is still less efficient than chain-drive, but not nearly as much as this video lets on, and are actually conditionally more efficient than chains and belts. Modern, high-end no-frills shafts (no fancy gearbox) can get 97% efficient power delivery _in all conditions and with minimal maintenance,_ while a similar chain-drive can expect 99% efficiency only under ideal conditions and can drop as low as 80% if you don't remember to clean and oil your chain after a muddy or dusty ride.
Also, I'd like to point out that he tried to make it seem like a stiffer frame would only benefit shaft-drive when that stiffer frame also benefits chains and belts just as much, and the area where the stiffness is needed doesn't actually effect ride quality. The stiffness is only needed to make sure the shaft stays in alignment and the gears remain correctly meshed, that same stiffness also keeps chains and belts aligned so they don't skip or jam, and keeps the rear wheel pointed in the correct direction so you aren't riding cock-eyed.
Look at the sharp teeth in them two discs imagine the injuries 😭
As a mechanic i have to say belt drives arent as maintenance free as they are said to be, yes they dont (really) need a lube BUT if not maintained to the correct tension they WILL eat or grind themselfs to destruction and wont last more then 6k km's....
I dont think chain drives are going to see huge jumps from where they are already either .... at least shaft drives opens up new horizons... thats how man progresses
Chain drives are already lighter, less complex, and 99% efficient on certain configurations, hard to improve upon that. Heavier, less efficient systems have room to grow.
As a consumer, i just buy the best that i can for my money and for my usage, and currently that's chain drive with derailleur.
"So why have these drive trains never taken off?". No pun intended.
Because the friction is enormous and engaging only 1-2 teeths isn't exactly strong point of any transmission, not to mention extremely high torque transmission like bicycle has.
@@petersvancarek Teeths? LOL!
@@DMSProduktions I will allow you to call it how do you choose, English isn't my first, not even my second language.
The fact remains, the bevel gear has much larger working surface compared to this engineering nightmare...
@@petersvancarek I know! The word 'teeth' in English IS the plural! There is no word as 'teeths' in English! 'Tooth' is the singular!
YW!
@@DMSProduktions you're quite the prick, aren't you?
From an engineer: The Driven Drivetrain is packed with design elements that necessitate a redesign, high complexity or crazy materials to work.
So the possibilities I see are:
1. It gets redesigned until the actual selling point is lost.
2. The problems caused by the design intent lead to a very complex product, with a lot of moving parts, therefore low efficiency/high cost/low reliability.
3. Alternatively they try to solve those issues with the amazing tools of material science, so new and untested materials, and parts that are very expensive.
Really sorry, but the design looks a bit like an Indigogo scam. Nevertheless, they might pull it off and create a revolutionary product. Can't know until you tried ^^
Motorcycle racers use chains, due to a power loss with shaft drives.
Right.. It was making me tired just watching this video of people peddling a bike with a Shaft Drive! Two 90 degree turns, one at the crank and one at the rear wheel, that is not good for efficiency, no matter how well it's made. With a chain drive, you have pretty much direct application of torque to the rear wheel, it's a perfect setup. Belts would be ok, but require being somewhat tight, therefore loosing efficiency. Plus some of the torque is lost in belt stretch as torque is applied.
Why use a shaft drive when you lose the fun of getting your pants leg caught in the chain.
I mean come on, we all love the fashion statement of having our right pants leg tucked into our sock.
I myself am more a fan of having my right pants leg frayed because I always forget to tuck it in.
i always roll up my right pant leg, it means i'm in a gang.
More due to application. You might be wearing loose pants biking to work in which case your point has merit. For anyone on a mountain bike I guarantee they aren't wearing khaki's.
I imagine these might also have an explosion safety factor in specific industry settings because you have no metal chain skipping over metal sprockets and it's all very contained and isolated. So in places you can't drive your car or use a conventional bike, these could potentially be handy?
All I can think of is the vast array of places gunk can get in on that thing.
its a cutaway to show you how it works,they are 100% enclosed
Pedal assist seems like a far better solution.
I was planning on building a shaft bike from scratch. My idea was that a BMZ trick bike shouldn't have an exposed chain and gears due to the grinding and constant impacts. I'm tired of breaking the front chain ring so i thought a shaft drive would keep it all inside. It's perfect for BMX because it's just one gear and the frames are typically stiff steel frames anyway. I was going to use a carbon fiber shaft and carbon wheels to make up the weight difference and to add strength to the shaft.
So far my major hurtles are the difficulty of tig welding. It's freaken hard. And now it's harder because i now know that I'm not original.
Almost no one is "original". Keep going. Sometimes a thing is worth doing simply for the satisfaction of doing it and learning along the way. In the end you'll still have a super cool bike, and have built it yourself!
Shaft drive bikes were built almost 200 years ago. It's almost impossible to think of any new idea for bicycles. Seriously, the USA originally had one patent office just for bicycles and one for EVERYTHING else. But you might be the one to crack the case.
That new system is a much more efficient method of switching between gearing ratios, but the only problem is that it is too easy for it to get clogged up because the ratio cog array attached to the rear cycle wheel is unprotected from crud from the riding surface. It might work well on a specially designed recumbent bike though.
I just wish the whole transmission could be effectively sealed off
Pedal assist seems like a far better solution.
Just get an internal hub transmission like shimano alfine.
@Alfred Wedmore you can use a belt with the internal gear box. That's really low maintenance. Only downside is that you need a frame that can "open up" to put the belt on. Might make the frame a bit less stiff.
You want a sealed transmission? Check this out: th-cam.com/video/S39oR_7Vwf8/w-d-xo.html
So with shaft drive, I can get two-wheel drive? perfect for winter!!
Check out the ROKON two wheel drive motorcycle, it has a shaft system with gearing to drive the front wheel. Originally built as a utility motorcycle for people who work in forestry, and for inspectors on utility lines.
You can do that with chain drive too. But amount of friction losses is enormous for both solutions, making them useless.
With the dawn of ebikes, you also have the issue that a shaft is actually not that much more efficient than a dynamo that gives extra power to the motor, and in terms of moving parts complexity when the bike is already an ebike, the dynamo is simpler and more reliable, and allows for absurdly flexible frames (like, it becomes viable to use elastic frames for suspension)