Hi Rob. I played with this idea to go onto a recumbent delta trike based on a design sold by a family design team here in Canada. Their build projects (and there did quite a few) used square tubing for many fabricated parts. I came up with another 'version' of the differential you describe there after getting my hands on two large "finger ratchet wrenches" - these are like a conventional square-drive socket ratchet wrench, but with no handle. They're meant to be used in tight spaces. I got a pair that took 1/2" drive sockets (I later revised the design to use 1" square drive socket wrenches) and after more than the usual messing around trying to do for 5 cents what any fool can do for $5, I had a differential real axle that worked quite well. At the time, I was planning to use 48-spoke 27" rimes for my rear wheels. A machinist in Australia very kindly made up a set of 48-spoke hubs, and (miracle of miracles) I found some high quality 48-spoke rims for sale by a British maker. At the time (2010-ish), the pair of rims cost just over CAD$110, plus 6 pounds 95p for postage. They arrived in three days - some kind of record in anyone's book. Since we have ice and snow about 8 months of the year, one over-riding concern was/is cold-weather operation. I also hoped to have an "electric assist" system that could be activated for steep hills, etc. The rear end - axles, bearings, ratchet-based freewheel/differential(s) plus the necessary frame were pretty much complete by 2013, along with about 2/3 of the rest of the frame and front end. Then someone stole the whole works, plus all of my welding gear. In the same period, I became permanently disabled and so was retired from engineering (cold-weather methanol fuels among other things) and there were two deaths in the family, all in a very short amount of time. My disability required quite a bit of revision to the basic recumbent delta trike, but I did get some plans drawn up. However, not being able to work (and therefore being without income), plus dealing with two separate family wills pretty much put the whole project on hold. Since then, because of an accident and new factors arising from disability, plans will be changing yet again. It was suggested to me to consider using motorcycle wheels for the rear pair, rather than bicycle wheels and rims. This idea has some merit, but make a home-brew differential more difficult. Reason #1 was simply tire and wheel strength. The most frequent points of failure on bicycles and tricycles here are flat tires and damaged rims. Of people who commute using a bike or trike, 44% report at least one flat tire every 10 days. The other main reason for considering motorcycle wheels was better traction and (by using Aluminum) a lighter overall rear assembly. If an electric assist was still a possibility, weight is a major problem. Being poor (where I once was not) has really made this proposition difficult and unlikely. There are very few "free" or inexpensive sources of modern batteries to be had. The cost of material and welding equipment for at least part of the frame being changed from steel to aluminum tubing is a big obstacle to this idea as well. Road conditions here are not ideal much of the year, but I mention that proposal in the interest of completeness. It seems unlikely and unaffordable at this stage. Anyhow, I love your design for this simple implementation of a working differential, and I have seen actual examples on hand-built trikes locally. Cheers from northwest Canada.
Brilliant, thanks Rob. For those rummaging through scrap yards.. The spin-on clusters / cassettes are typically found on old bikes. Newer bikes have the free-wheel built into the hub.
For most users, 2 wheel drive trikes are overcomplicated. I built a semi recumbent delta trike with one wheel drive over 12 years ago and have done more than 25,000km on it. I have only ever had traction problems in mud and snow. Making it single wheel drive made loads of problems go away and gave a load of advantages. To move the drive from the centreline to the left wheel, I used a technique from Atomic Zombie. This adds a separate drive shaft half way between the pedals and rear wheel, with one chain from the crank to this shaft and another chain from the shaft to the driven rear wheel. The shaft is made from a bicycle wheel hub, split it in half and a tube welded between the 2 halves. A 10mm steel rod is easily threaded with the standard bike axle threads and the old bearings reused. If a rear wheel hub is used, rear derailleur gears can be used in the centre shaft, as well as the rear wheel, doing away with the dreadful front derailleurs, which are always unreliable. By using this technique, I have 6 front gears, 7 rear gears, giving a total of 42 gears!!! Other advantages are an open area between the rear wheels for a cargo box, shorter chains (recumbents often have very long chains) and everything is easy to access for maintenance. I am thinking of adding electric augmentation on the currently undriven rear wheel by simply replacing the wheel with one with a hub motor.
Years ago I watched your channel for everything about batteries in EVs. So I’m doing research on tricycle axles and voila!? Again you’ve popped up in my search… We must have the same train of thought because I’ve subscribed again lol.
hi, first comment; I came with that solution days ago and marvel myself because this arrangement doesn't have the problem of the xhausting power through the fasttest wheel. So the power alway goes with the slower wheel which have the less weight in a corner. In case the inner driven wheel drift in a corner, then the other wheel automaticly engage as magic. Isn't that awesome?. The only problem is that in a turn always will be just a driven wheel. I think your brake is doing nothing, it had to be attached directly to the wheels or you will need a two way freewheel. Then, also you'll be able to pedal backwards. Cheers, and thanks for be so caring with your audience.
I am going to use the brake disk for something else mate - I want this motor and pedal driven - that's a bit awkward unless you use two input cog - so the brake disk here will become an input cog
Great video. I’ve been thinking about building something similar for my grandsons. I was stuck on the rear axle. Pretty sure they are not ready for a drift trike lol This video was as if I had ordered a sandwich and you were telling me what is on it Thank you, kind sir
That welder has come in really handy. I use mine more than I thought I would. I need to get a large spring clamp out the other day and one blob of weld and a pair of grips and away it came lol
Ive thought about doing this but the only way I can figure out braking would be a disc brake beside each wheel with a brake cable splitter to y out one cable into two so that both rear brakes would be operated by one brake lever. This is better than a normal differential because it's still a positive traction rear end. Using hydraulic brake line would be better than a cable to split and it would be a more equal pressure to each rear caliper.
Awesome project... I do have a slightly silly question. Is the brake attached to the axle that the cog is attached to? Would this not lead to the freewheel engaging when you brake, meaning no brakes on the back?
Great way of making a freewheel very inventive thinking only one question when you apply the disc brake it will stop the axel but surely the freewheels will just carry on so the brake will only work if the trike is going backwards or am I missing something
When braking the weight of the bike stops the wheel from going forward,the freewheel is when the wheel rotates backwards or one wheel is moving slower ( causing the wheel to move backwards compared to the driving axel).A really good question.
I'd tend to agree, if you put the brakes on, the wheels will just Freewheel... because on a bike, the brakes are on the wheels, not the axle. However Robert is a genius and I can't wait to see his fix
I've been thinking about delta drive arrangements also. My idea is to have 2 wheels mounted on non driven axle. The wheels on ratchet drive are attached with one wheel reversed so both drive cogs are facing inboard. You then drive each wheel from a common drive shaft. This should allow one wheel to travel faster than the other around corners, but drive both wheels when going straight.
Yes I thought about that too, but it would require a separate chain for the drive cog for each wheel, and a drive axle with three cogs on it, one on each end for each wheel and one in the middle to link to the gears. ...and of course a bespoke cycle frame with a bearing each side for the midmounted drive axle to run in. Seems a lot more complex, but it would work.
Oh yeah, there is a distinct advantage though, with having a midmounted drive shaft linking to each wheel separately.... If you use that drive shaft as a pivot point you can have each wheel on independent suspension. Perfect for off road scrambling.
Having one wheel drive allows you to literally pivot the trike around the non driven wheel, but only in one direction, this is convenient if you are trying to manoeuvre in a tight space. Using this arrangement means that all drive goes to the slowest turning turning wheel making tight turns in either direction difficult, with one wheel drive it is only a problem in one direction
Having driven a rear wheel drive road car with a locked differential I can tell you unsurprisingly it did not like roundabouts. On a comedy note you appear to have a disc brake on the rear axle kart style, I suspect that you have spotted the issue with that. Keep up the good work, some great ideas.
I feel like, but maybe I am mistaken since I'm not a mechanic expert, that it isn't an actual differential, but a double freewheel. While it prevents the wheels from sliding while turning (which is really nice already), it does not transfers the torque on the slow wheel toward the fast wheel, and instead do the opposite. Here is a thought experiment to highlight the difference with a "traditional" differential : Say your trike only has a brake on the left rear wheel. Put your trike resting on its frame so the wheels are not touching the ground. Apply the brake so it is preventing the left rear wheel from spinning. Try pushing on the pedals : you should not be able to move them, in the same way a regular bike's freewheel prevents you from pedaling if the rear wheel is applied and prevents the real wheel from spinning. Now, on a "traditional" differential, stopping one of the two rear wheels would not prevent you from pedaling, and instead the other, non stopped wheel would spin. So in case of a "traditional" differential, torque from pedaling is balanced between the two wheels, so anytime, the two wheels are pushing. On the other hand, your dual freewheel differential only applies the torque to the slowest wheel. If feel like it would not make much difference in many cases, as most people are already fairly happy with trikes having only one of the rear wheels receiving torque. The only case where I feel like it can make a difference is in really tight turns, like a U-turn. In that case, assuming the front wheel of the trike can be nearly parallel to the rear wheel axis, the wheel at the interior of the curve will move really few, and the wheel at the exterior will appear to be "circling" around it, so in that very case it would be preferable to have a traditional differential to have the exterior wheel receive torque to help it circle around the interior wheel. However, keep in mind this is only guesswork and I didn't tested it with actual simulation nor experiment, and likely it would at most cause a noticeable difference in smoothness in U-turns between dual freewheel and traditional differentials, but probably not enough to have a need for a traditional differential, which are much more costly and harder to find. Also, building a traditional differential from scratch can be very hard, as it requires high precision for it to be efficient, and while it would solve the cost and U-turn inefficiency, it would also decrease overall efficiency of pedaling over a simple dual freewheel. EDIT : about difficulty of making actual differential.
So, unless Ive got this wrong, the drive goes to the inner (slower) wheel not the outer wheel? Which is the wrong way round for a trike because the inner weel will lift off the floor in a curve and all traction will be lost. You always need traction to the outer wheel.
There may be a problem as stated delivering power only to the inside wheel. It will be fun to see if it works well. Can you lock them and video the comparison to a rigid axle?
@Vince Williams - If the inner wheel lifts and spins then the traction will go to the outer wheel. BUT, if the inner wheel has grip then the outer wheel will freewheel. However, this does not sound like what @Robert Murray-Smith was intending. Ideally you would want the drive to go to the wheel with the greater mechanical advantage (the outer), especially when starting from rest.
@@ThinkingandTinkering But it is, Robert. I rolled my trike on gravel in the 1940s, partly because I could not lean far enough and pedal at the same time, partly because the _only_ driven wheel on my trike was on the inside of the turn, so when it lifted traction was lost, which caused a deceleration pitch forward, and it 'high-sided' me, bigtime! Of course I was also going _much_ too fast - and got the gravel-rash to prove it. Later, at engineering school we raced a Bond 875, ooh my!🙃
Need to move the brake disk to the wheels, though. Braking the axle will just stop the axle, allowing the freewheel to operate and not slowing you down at all. Very surprised indeed, that Robert didn’t consider this. Not like him to miss something like that. I guess it proves he’s human
It's basically, the angular momentum, in forward directions cannot be slower than that of the axle. But since it its a freewheel, it can alway be faster. So the wheel wit less angular momentum, will always receive 100% of power.
VERY CLEVER HOW YOU MADE THAT LEFT DRIVE WORK AROUND, HOWEVER THEY ALREADY MAKE A LEFT HAND THREAD FREEWHEEL THAT COST THE SAME AS A RIGHT HAND OF ABOUT $10-$15 EACH. LET ME KNOW IF YOU WOULD LIKE A LINK TO THEM.
I used sprag clutches to do exactly the same thing. These are like bearings that engage in one direction and free wheel in the other. Also, you can use 2 on each wheel in place of the bearings. I got the sprag cluches off old printers.
@ lasentinal - thanks for that! Been looking for 'scrap' sprag clutches for a pedaling project for ages now. Is any particular brand/type of printer best?
@@250tegra I found the larger Xerox printers and photo copiers to be the best, particularly if these have quarter inch axles for the rollers. Other brands are okay as well, as long as you match the sizes. The trick is to use as big of acluth as you can and as many as you can for each wheel.
@@lasentinal Many thanks! I'm fooling with a thing that 'works' ok with a couple of freewheels, except for the pawl take-up which spoils the fun. It uses thin kevlar line wrapped around the clutch or freewheel, it is pulled by a foot-pedal to turn the wheel. A second clutch/freewheel is operated by the other foot pedal. Needs some cunning routing to balance them and get them to 'return' for the next stroke, but much lighter than chains, and there seem to be ways to vary the gearing geometrically. Thanks again, I will hopefully be off to a re-cycling site at the weekend!
I'm building a tadpole 3wheeler using two 16in rear bike wheels. The have freewheel coaster brake hubs. The wheels are still driven by the chain and pedal cranks, but I cut the cranks to just stubs and are connecting the two with a shaft. So the shaft spins the cranks that drives both wheels. I thought this will work like a differential, but it isn't the same, as when the shaft is powered, both wheels must spin at the same speed, but if you stop powering them they will freewheel and can turn at different speeds. So you can't power through a turn like a true differential. Just thought someone might like to know about this setup, will have this project on my channel soon.
If you appky braking to the axle you wont stop, because the wheels will free wheel, you need to brake from the rim or outer sleeve of the hubs, or come up with another solution.
A question regarding the "no reverse" statement (6:32): As far as I know, "normal" (two wheeled, geared) bicycles also don't reverse, and pushing them backwards engages the pedals and rotates them back. Obviously there's a reason, or you wouldn't have mentioned it, so why did you? Thanks
That's beautiful. Using a tool to modify the hub, it looks fairly simple I wonder does it need two brake discs to keep the vehicle from pulling to one side, when you apply the brake?
oh my god, you sir are a genious! that's so simple that I was not even thinking about doing this kind of solution :D but one question though, the threads on the wheels are in a different order once they are flipped, so one wheel tightens as it spins, the other one will untighten, or am I missing something? also, will the brake be usable on the shaft once it's all mounted up?
You would assume that cars could use a similar free wheel and lose the geared differential.What am i missing as cars could pin the rear wheels when reverse is selected? Great show 🎉🎉🎉
Said 'freewheel' so many times! Seems like a cool design, putting 2 freewheel things on one side to reverse direction doesn't make sense intuitively, but it seemed to work i guess.
This looks like a nice application for unidirectional roller clutches. They're simpler to make than a freewheel and they don't click. Sometimes they are called "one way bearings". I never would have thought to use a freewheel as a differential though! :-)
@@Surestick88 Yes, the ratchet needs a larger rotation to engage than a roller clutch, but wear can be a problem since the clutch needs tight tolerances.
we need a fixed sprocket drive arrangement so the wheel can be driven backwards too (for an autonomous land rover). do you know of any such axle that would work with these hollow axle wheels for trikes maybe? needs to drive the wheels independently too so maybe two short axles
Pardon my ignorance here but I’m looking into making a 2 stroke converted trike from a run of the mill, inexpensive 7speed trike. I’ve been trying to figure out how to fix the rear sprocket (the drive cog that comes with the conversion kit) to the axle without f’in anything up. I might have to get rid of the rear brakes but I’m not worried about that. I haven’t gotten the bike itself yet but was wondering if the newer bikes (getting it brand new) are two freewheels on the back and not a fixed axle so I wouldn’t have to worry too much about slight turns at speed. I won’t be going very fast anyway but just wondering if the motor being fixed to the middle of the axle will mess that up. Maybe a stupid thing to ask I hope some of that made sense. But thanks to videos like this my understanding is steadily growing!!
The inner wheel on a corner will be the driver, meaning there will be either a slowdown through the pedal system or an acceleration of the trike. We may also see that if the velocity through the corner is sufficient there will be an overturning moment about the outer wheel which causes sufficient decrease in traction of the inner wheel that the outer wheel drives while the inner wheel spins faster! I await the practical evaluation with great interest!
Possibly the most ideal design would be to get hold of two single speed freewheel hubs that have internal drum brakes too from the design of the 1930s. They are still being made to this day in countries where low maintenance and harsh environments are the main concern like in India.
Brilliant idea. Although I do not totally get how it works, I am sure I will do at some point. The diff problem has always been a biggy when it comes to 2 wheels at the back. I have tried a cart with one powered wheel, but even that system works best when the powered wheel is on the outside of the corner.
Put simply, it's basically an axle with a one-way ratchet on each end that each wheel is fixed to. When the axle turns, it engages with the stops of the ratchets and drives the wheels. But when you turn a corner, whichever wheel is on the outside will turn faster than the wheel on the inside because it has further to go and because the wheel on the inside is being driven slower, the other wheel on the outside will ''freewheel' past the movement of the driven axle. Think of it like what happens on a normal bicycle if the driven rear wheel is turning faster that you are peddling, it just freewheels over the ratchet on the drive cog.
Damn, you're a smart cookie. Need more like you in this world. About the only topic you haven't covered is DIY fuel for a home made missile / rocket, lol. 🤣
Can you explain the best way to introduce air to a wood or gas burner .using the hot air from the room you are trying to heat causing drafts. or the colder air from from under the floor Alex.
Good point. Simpler to build too. Then you get to keep both adjustable rear hubs and mount the motor to the pedal area or sproket. Now you got a transmission and low gear for hills. Backing up not that important to me.
@@ThinkingandTinkering you could use less powerful motors and still use the same power consumption for minimal cost difference. but that is just a thought for redundancy and less complication for those without a welder.
if we use two motors then how will change the power of both ,we can synchronize them which will work for straight movement but what about turning problem??? you would need to decrease power in one motor while turining
Modern high performance motorcycles often have two discs for braking, there is a valve body that the lines attach to, so that the master cylinder activated applies equal pressure to both slave cylinders at the same time. I forget what the part is called, in an automobile it is called a metering valve, I think. Its mounted to the frame rail of the auto chassis, near the main cross member that holds up the transmission. It's not a serviceable part.
cool, now someone attach a 6" Rhombic drive Stirling engine to that axal with a paint on heater end, & vacuum flask cold end in the right orientation, + mostly magnetic Stirling cycled copper coiled heads+ magnets+ caps to feed the encased heater, call it good as a base low energy input amplifying device to be optimised ^_~
What is puzzling is that since the wheels can move freely forward with the axle not moving you essentially cannot brake by stopping the axle. Only whay i can think is having independant brakes in each wheel . Am i missing something?
I thought I was the first person to imagine this, glad to know it is actually used
Ingenious use of those freewheel assemblies! I love it!
cheers mate
use calipers
I made both types of trikes back in my youth (1970's) It was a baptism of fire when I figured out about the issues of not having a differential :O
lol - I'll bet lol
Hi Rob. I played with this idea to go onto a recumbent delta trike based on a design sold by a family design team here in Canada. Their build projects (and there did quite a few) used square tubing for many fabricated parts. I came up with another 'version' of the differential you describe there after getting my hands on two large "finger ratchet wrenches" - these are like a conventional square-drive socket ratchet wrench, but with no handle. They're meant to be used in tight spaces. I got a pair that took 1/2" drive sockets (I later revised the design to use 1" square drive socket wrenches) and after more than the usual messing around trying to do for 5 cents what any fool can do for $5, I had a differential real axle that worked quite well. At the time, I was planning to use 48-spoke 27" rimes for my rear wheels. A machinist in Australia very kindly made up a set of 48-spoke hubs, and (miracle of miracles) I found some high quality 48-spoke rims for sale by a British maker. At the time (2010-ish), the pair of rims cost just over CAD$110, plus 6 pounds 95p for postage. They arrived in three days - some kind of record in anyone's book.
Since we have ice and snow about 8 months of the year, one over-riding concern was/is cold-weather operation. I also hoped to have an "electric assist" system that could be activated for steep hills, etc. The rear end - axles, bearings, ratchet-based freewheel/differential(s) plus the necessary frame were pretty much complete by 2013, along with about 2/3 of the rest of the frame and front end. Then someone stole the whole works, plus all of my welding gear. In the same period, I became permanently disabled and so was retired from engineering (cold-weather methanol fuels among other things) and there were two deaths in the family, all in a very short amount of time.
My disability required quite a bit of revision to the basic recumbent delta trike, but I did get some plans drawn up. However, not being able to work (and therefore being without income), plus dealing with two separate family wills pretty much put the whole project on hold. Since then, because of an accident and new factors arising from disability, plans will be changing yet again.
It was suggested to me to consider using motorcycle wheels for the rear pair, rather than bicycle wheels and rims. This idea has some merit, but make a home-brew differential more difficult. Reason #1 was simply tire and wheel strength. The most frequent points of failure on bicycles and tricycles here are flat tires and damaged rims. Of people who commute using a bike or trike, 44% report at least one flat tire every 10 days. The other main reason for considering motorcycle wheels was better traction and (by using Aluminum) a lighter overall rear assembly. If an electric assist was still a possibility, weight is a major problem. Being poor (where I once was not) has really made this proposition difficult and unlikely. There are very few "free" or inexpensive sources of modern batteries to be had. The cost of material and welding equipment for at least part of the frame being changed from steel to aluminum tubing is a big obstacle to this idea as well.
Road conditions here are not ideal much of the year, but I mention that proposal in the interest of completeness. It seems unlikely and unaffordable at this stage. Anyhow, I love your design for this simple implementation of a working differential, and I have seen actual examples on hand-built trikes locally. Cheers from northwest Canada.
Brilliant, thanks Rob. For those rummaging through scrap yards.. The spin-on clusters / cassettes are typically found on old bikes. Newer bikes have the free-wheel built into the hub.
spin-on cogs are still in use **new** in BMX and artistic cycling bicycles
One very OBVIOUS problem is your brake is no longer functional as both wheels over-run the axle. Stopping the axle does NOTHING to stop the tricycle.
That was cunning. I love lateral thought.
cheers mate
How do i buy these freewheel without the gears? What are they called? @ThinkingandTinkering
Not to nitpick, but with that arrangement, it looks like the brake would be ineffective (unless you were rolling backward).
For most users, 2 wheel drive trikes are overcomplicated. I built a semi recumbent delta trike with one wheel drive over 12 years ago and have done more than 25,000km on it. I have only ever had traction problems in mud and snow.
Making it single wheel drive made loads of problems go away and gave a load of advantages. To move the drive from the centreline to the left wheel, I used a technique from Atomic Zombie. This adds a separate drive shaft half way between the pedals and rear wheel, with one chain from the crank to this shaft and another chain from the shaft to the driven rear wheel. The shaft is made from a bicycle wheel hub, split it in half and a tube welded between the 2 halves. A 10mm steel rod is easily threaded with the standard bike axle threads and the old bearings reused. If a rear wheel hub is used, rear derailleur gears can be used in the centre shaft, as well as the rear wheel, doing away with the dreadful front derailleurs, which are always unreliable.
By using this technique, I have 6 front gears, 7 rear gears, giving a total of 42 gears!!! Other advantages are an open area between the rear wheels for a cargo box, shorter chains (recumbents often have very long chains) and everything is easy to access for maintenance.
I am thinking of adding electric augmentation on the currently undriven rear wheel by simply replacing the wheel with one with a hub motor.
A very neat solution well thought out.😊
This man has helped me so very much. I'm making a Delta trike camper and this made it a peace of cake, thank you!
Me too! May not use this method though as i cant weld.
Years ago I watched your channel for everything about batteries in EVs.
So I’m doing research on tricycle axles and voila!? Again you’ve popped up in my search…
We must have the same train of thought because I’ve subscribed again lol.
hi, first comment;
I came with that solution days ago and marvel myself because this arrangement doesn't have the problem of the xhausting power through the fasttest wheel. So the power alway goes with the slower wheel which have the less weight in a corner. In case the inner driven wheel drift in a corner, then the other wheel automaticly engage as magic. Isn't that awesome?. The only problem is that in a turn always will be just a driven wheel.
I think your brake is doing nothing, it had to be attached directly to the wheels or you will need a two way freewheel. Then, also you'll be able to pedal backwards.
Cheers, and thanks for be so caring with your audience.
I am going to use the brake disk for something else mate - I want this motor and pedal driven - that's a bit awkward unless you use two input cog - so the brake disk here will become an input cog
@@ThinkingandTinkering ¿like a clutch? I'm almost sure you won't use a planetary.
Great video. I’ve been thinking about building something similar for my grandsons. I was stuck on the rear axle. Pretty sure they are not ready for a drift trike lol
This video was as if I had ordered a sandwich and you were telling me what is on it
Thank you, kind sir
What a lovely bloke! Pleasure to learn from you sir!
That welder has come in really handy. I use mine more than I thought I would. I need to get a large spring clamp out the other day and one blob of weld and a pair of grips and away it came lol
it really is an awesome thing!
Ive thought about doing this but the only way I can figure out braking would be a disc brake beside each wheel with a brake cable splitter to y out one cable into two so that both rear brakes would be operated by one brake lever. This is better than a normal differential because it's still a positive traction rear end. Using hydraulic brake line would be better than a cable to split and it would be a more equal pressure to each rear caliper.
That's genius
cheers mate
Un maestro... No hablo inglés y lo endendí igual. Muy Genioooooo
Wow now that was some really good info!!
I am glad you found it useful
Bravissimo...un modo semplicissimo per il differenziale!! Bravissimo 👏👏👍👍🥇🥇
Good idea but I think the brake won't work the axle will stop spinning but the wheels will continue to rotate
Yes, you are right
Hi Rob. That is so clever! And so simple.
cheers mate
as a MadMax fan I just love this video
Awesome project... I do have a slightly silly question. Is the brake attached to the axle that the cog is attached to? Would this not lead to the freewheel engaging when you brake, meaning no brakes on the back?
yep, no brakes
I thought about it, but i couldn't solve the "wrong" turning direction. Well played, mate.
By the way, how did you solve the breaking problem?
Thanks for the update on the wheel ideas 😊 out standing buddy 😄 thanks again.
Ultimate Frankenstein posi traction. I love it. Dirt cheap too. Except for the welding rod and electricity/welder. 😂
Great way of making a freewheel very inventive thinking only one question when you apply the disc brake it will stop the axel but surely the freewheels will just carry on so the brake will only work if the trike is going backwards or am I missing something
When braking the weight of the bike stops the wheel from going forward,the freewheel is when the wheel rotates backwards or one wheel is moving slower ( causing the wheel to move backwards compared to the driving axel).A really good question.
I'm wondering the same. I don't think the disc brake will stop the bike.
I'd tend to agree, if you put the brakes on, the wheels will just Freewheel... because on a bike, the brakes are on the wheels, not the axle. However Robert is a genius and I can't wait to see his fix
Well the same exact set up is on a bike hub and it stops.
Maybe one stops and one does not?
Make both stop?
Yes if brake is connected to same sleeve as drive, then wheels will freewheel under braking. Brake has to be connected to outer sleeve or wheel.
I've been thinking about delta drive arrangements also. My idea is to have 2 wheels mounted on non driven axle. The wheels on ratchet drive are attached with one wheel reversed so both drive cogs are facing inboard. You then drive each wheel from a common drive shaft. This should allow one wheel to travel faster than the other around corners, but drive both wheels when going straight.
interesting mate - i 'see' things better with a model - can you make one to show me what you mean exactly?
Yes I thought about that too, but it would require a separate chain for the drive cog for each wheel, and a drive axle with three cogs on it, one on each end for each wheel and one in the middle to link to the gears. ...and of course a bespoke cycle frame with a bearing each side for the midmounted drive axle to run in. Seems a lot more complex, but it would work.
Oh yeah, there is a distinct advantage though, with having a midmounted drive shaft linking to each wheel separately.... If you use that drive shaft as a pivot point you can have each wheel on independent suspension. Perfect for off road scrambling.
Having one wheel drive allows you to literally pivot the trike around the non driven wheel, but only in one direction, this is convenient if you are trying to manoeuvre in a tight space. Using this arrangement means that all drive goes to the slowest turning turning wheel making tight turns in either direction difficult, with one wheel drive it is only a problem in one direction
Thanknyou for this relaxt video..best wishes from the middle of the Netherlands
Having driven a rear wheel drive road car with a locked differential I can tell you unsurprisingly it did not like roundabouts. On a comedy note you appear to have a disc brake on the rear axle kart style, I suspect that you have spotted the issue with that. Keep up the good work, some great ideas.
i was thinking the very same thing! imagine the poor bastard that grabs the brake lever and all he hears ar the prawls clicking!
I feel like, but maybe I am mistaken since I'm not a mechanic expert, that it isn't an actual differential, but a double freewheel.
While it prevents the wheels from sliding while turning (which is really nice already), it does not transfers the torque on the slow wheel toward the fast wheel, and instead do the opposite.
Here is a thought experiment to highlight the difference with a "traditional" differential :
Say your trike only has a brake on the left rear wheel. Put your trike resting on its frame so the wheels are not touching the ground. Apply the brake so it is preventing the left rear wheel from spinning. Try pushing on the pedals : you should not be able to move them, in the same way a regular bike's freewheel prevents you from pedaling if the rear wheel is applied and prevents the real wheel from spinning.
Now, on a "traditional" differential, stopping one of the two rear wheels would not prevent you from pedaling, and instead the other, non stopped wheel would spin.
So in case of a "traditional" differential, torque from pedaling is balanced between the two wheels, so anytime, the two wheels are pushing. On the other hand, your dual freewheel differential only applies the torque to the slowest wheel.
If feel like it would not make much difference in many cases, as most people are already fairly happy with trikes having only one of the rear wheels receiving torque.
The only case where I feel like it can make a difference is in really tight turns, like a U-turn. In that case, assuming the front wheel of the trike can be nearly parallel to the rear wheel axis, the wheel at the interior of the curve will move really few, and the wheel at the exterior will appear to be "circling" around it, so in that very case it would be preferable to have a traditional differential to have the exterior wheel receive torque to help it circle around the interior wheel.
However, keep in mind this is only guesswork and I didn't tested it with actual simulation nor experiment, and likely it would at most cause a noticeable difference in smoothness in U-turns between dual freewheel and traditional differentials, but probably not enough to have a need for a traditional differential, which are much more costly and harder to find. Also, building a traditional differential from scratch can be very hard, as it requires high precision for it to be efficient, and while it would solve the cost and U-turn inefficiency, it would also decrease overall efficiency of pedaling over a simple dual freewheel.
EDIT : about difficulty of making actual differential.
Awesome! So straightforward. Thank you Thank you Thank you!
06:15: How did you preserved the oil in the freewheel as long as you heated it?
Awesome explanation & walk through demonstration 👍
Remarkable idea indeed!!!
So, unless Ive got this wrong, the drive goes to the inner (slower) wheel not the outer wheel? Which is the wrong way round for a trike because the inner weel will lift off the floor in a curve and all traction will be lost. You always need traction to the outer wheel.
that doesn't sound right mate
There may be a problem as stated delivering power only to the inside wheel. It will be fun to see if it works well. Can you lock them and video the comparison to a rigid axle?
@Vince Williams - If the inner wheel lifts and spins then the traction will go to the outer wheel. BUT, if the inner wheel has grip then the outer wheel will freewheel. However, this does not sound like what @Robert Murray-Smith was intending. Ideally you would want the drive to go to the wheel with the greater mechanical advantage (the outer), especially when starting from rest.
@@ThinkingandTinkering But it is, Robert. I rolled my trike on gravel in the 1940s, partly because I could not lean far enough and pedal at the same time, partly because the _only_ driven wheel on my trike was on the inside of the turn, so when it lifted traction was lost, which caused a deceleration pitch forward, and it 'high-sided' me, bigtime!
Of course I was also going _much_ too fast - and got the gravel-rash to prove it. Later, at engineering school we raced a Bond 875, ooh my!🙃
Great Work Earthling
Bless Up :)
Thank you! Cheers!
That break disk is useless now though
Need to move the brake disk to the wheels, though. Braking the axle will just stop the axle, allowing the freewheel to operate and not slowing you down at all. Very surprised indeed, that Robert didn’t consider this. Not like him to miss something like that.
I guess it proves he’s human
Simply brilliant!
It's basically, the angular momentum, in forward directions cannot be slower than that of the axle. But since it its a freewheel, it can alway be faster. So the wheel wit less angular momentum, will always receive 100% of power.
VERY CLEVER HOW YOU MADE THAT LEFT DRIVE WORK AROUND, HOWEVER THEY ALREADY MAKE A LEFT HAND THREAD FREEWHEEL THAT COST THE SAME AS A RIGHT HAND OF ABOUT $10-$15 EACH. LET ME KNOW IF YOU WOULD LIKE A LINK TO THEM.
No need to shout pal
@@bigsteve6729 I AM VISION IMPAIRED, I USE CAPS AS AN VISUAL AID. NOT SHOUTING.
Yes please do, as I'm no welder! A link would help me so much T.KCSS.
I would love a link to them !
TY !
Thanks for that information. I am certainly interested!!!
I used sprag clutches to do exactly the same thing. These are like bearings that engage in one direction and free wheel in the other. Also, you can use 2 on each wheel in place of the bearings. I got the sprag cluches off old printers.
@ lasentinal - thanks for that! Been looking for 'scrap' sprag clutches for a pedaling project for ages now. Is any particular brand/type of printer best?
@@250tegra
I found the larger Xerox printers and photo copiers to be the best, particularly if these have quarter inch axles for the rollers.
Other brands are okay as well, as long as you match the sizes.
The trick is to use as big of acluth as you can and as many as you can for each wheel.
@@lasentinal Many thanks! I'm fooling with a thing that 'works' ok with a couple of freewheels, except for the pawl take-up which spoils the fun. It uses thin kevlar line wrapped around the clutch or freewheel, it is pulled by a foot-pedal to turn the wheel. A second clutch/freewheel is operated by the other foot pedal. Needs some cunning routing to balance them and get them to 'return' for the next stroke, but much lighter than chains, and there seem to be ways to vary the gearing geometrically. Thanks again, I will hopefully be off to a re-cycling site at the weekend!
@@250tegra
Have seen Gates Belt Drives. These can be easily adapted and are lighter and more durable than chains
I'm building a tadpole 3wheeler using two 16in rear bike wheels. The have freewheel coaster brake hubs.
The wheels are still driven by the chain and pedal cranks, but I cut the cranks to just stubs and are connecting the two with a shaft.
So the shaft spins the cranks that drives both wheels. I thought this will work like a differential, but it isn't the same, as when the shaft is powered, both wheels must spin at the same speed, but if you stop powering them they will freewheel and can turn at different speeds. So you can't power through a turn like a true differential.
Just thought someone might like to know about this setup, will have this project on my channel soon.
Great explanation.
cheers mate
If you appky braking to the axle you wont stop, because the wheels will free wheel, you need to brake from the rim or outer sleeve of the hubs, or come up with another solution.
Thanks Rob, i want to make a trike, and have been thinking about drive arrangement.
cheers mate
What's the brake disc for?
Wonderful! Thank you!!!! Watched to the end. Already subbed. Added the bell! 🛎
Thank you for the great information and I'm hoping to be able to follow you, and make this as well
Andrea, Jasper and George the Pigeon. XxX
cheers mate - rememeber I do change stuff based on feedback - so this will change but only a little - the basics will remain the same
A question regarding the "no reverse" statement (6:32):
As far as I know, "normal" (two wheeled, geared) bicycles also don't reverse, and pushing them backwards engages the pedals and rotates them back.
Obviously there's a reason, or you wouldn't have mentioned it, so why did you?
Thanks
That's beautiful. Using a tool to modify the hub, it looks fairly simple
I wonder does it need two brake discs to keep the vehicle from pulling to one side, when you apply the brake?
oh my god, you sir are a genious! that's so simple that I was not even thinking about doing this kind of solution :D but one question though, the threads on the wheels are in a different order once they are flipped, so one wheel tightens as it spins, the other one will untighten, or am I missing something? also, will the brake be usable on the shaft once it's all mounted up?
You would assume that cars could use a similar free wheel and lose the geared differential.What am i missing as cars could pin the rear wheels when reverse is selected? Great show 🎉🎉🎉
Said 'freewheel' so many times! Seems like a cool design, putting 2 freewheel things on one side to reverse direction doesn't make sense intuitively, but it seemed to work i guess.
this is amazing. I'm working on my alt ev also at the moment
This looks like a nice application for unidirectional roller clutches. They're simpler to make than a freewheel and they don't click. Sometimes they are called "one way bearings". I never would have thought to use a freewheel as a differential though! :-)
They probably have faster lock-up than most freewheels as well.
@@Surestick88 Yes, the ratchet needs a larger rotation to engage than a roller clutch, but wear can be a problem since the clutch needs tight tolerances.
we need a fixed sprocket drive arrangement so the wheel can be driven backwards too (for an autonomous land rover). do you know of any such axle that would work with these hollow axle wheels for trikes maybe? needs to drive the wheels independently too so maybe two short axles
Pardon my ignorance here but I’m looking into making a 2 stroke converted trike from a run of the mill, inexpensive 7speed trike. I’ve been trying to figure out how to fix the rear sprocket (the drive cog that comes with the conversion kit) to the axle without f’in anything up. I might have to get rid of the rear brakes but I’m not worried about that. I haven’t gotten the bike itself yet but was wondering if the newer bikes (getting it brand new) are two freewheels on the back and not a fixed axle so I wouldn’t have to worry too much about slight turns at speed. I won’t be going very fast anyway but just wondering if the motor being fixed to the middle of the axle will mess that up. Maybe a stupid thing to ask I hope some of that made sense. But thanks to videos like this my understanding is steadily growing!!
The brake on the axle is not going to work now!
The inner wheel on a corner will be the driver, meaning there will be either a slowdown through the pedal system or an acceleration of the trike.
We may also see that if the velocity through the corner is sufficient there will be an overturning moment about the outer wheel which causes sufficient decrease in traction of the inner wheel that the outer wheel drives while the inner wheel spins faster!
I await the practical evaluation with great interest!
cheers mate
Great work 👏 👍 👌
Hello Robert what axel are you using for this project please
Brilliant, thanks for sharing the information 👍
Just brilliant!
cheers mate
Possibly the most ideal design would be to get hold of two single speed freewheel hubs that have internal drum brakes too from the design of the 1930s. They are still being made to this day in countries where low maintenance and harsh environments are the main concern like in India.
Forgot to mention that you would then need to just refit the ratchet mechanism the other way round which is much simpler on the older modular designs.
Brilliant idea. Although I do not totally get how it works, I am sure I will do at some point. The diff problem has always been a biggy when it comes to 2 wheels at the back. I have tried a cart with one powered wheel, but even that system works best when the powered wheel is on the outside of the corner.
Put simply, it's basically an axle with a one-way ratchet on each end that each wheel is fixed to. When the axle turns, it engages with the stops of the ratchets and drives the wheels. But when you turn a corner, whichever wheel is on the outside will turn faster than the wheel on the inside because it has further to go and because the wheel on the inside is being driven slower, the other wheel on the outside will ''freewheel' past the movement of the driven axle. Think of it like what happens on a normal bicycle if the driven rear wheel is turning faster that you are peddling, it just freewheels over the ratchet on the drive cog.
@@penfold7800 OK, thanks for that explanation you have made it much clearer now.
The nice shiny brake disk is now useless! no brakes on the rear axle, BACK to the drawing board!
Damn, you're a smart cookie. Need more like you in this world. About the only topic you haven't covered is DIY fuel for a home made missile / rocket, lol. 🤣
lol - not allowed to with TH-cam policy on explosives lol
What if you use a one way freewheel, will it be able to reverse?
How do you get all that to pass through the frame holes ???
Up to the welding I was entertaining hope for my cambered rear wheels with independent axles.
3:58. You don’t use a punch to remove those, you use a chain spanner
if you have a chain spanner - if you don't - use a punch
@@____________________________.x in the good ole USA we call them chain braker
pretty good idea, am gonna try it...one day
I have noted you have some physical aspects of you design presented backwards.
The inner wheels is the drive wheel in turns with your design.
Can you explain the best way to introduce air to a wood or gas burner .using the hot air from the room you are trying to heat causing drafts. or the colder air from from under the floor Alex.
Thank you! Thank you! Thank you!
good job mate
Does this keep the breaks from working?
@Bafumat - Yup! But Robert has a work-around - mount brake disks directly onto the hubs - the brake disk on the axle came with the kit.
Do you have any drawings of this differential? I plan to build one but I think I'm missing something.
This is essentially exactly how a detroit locker works.
For the next video you can show us the crash when the brakes don’t work.
You held a piece and said because of this bit. What I want to know is where do you get this bit?
Like what shops sell them. Bike Shop or hardware stores ect.?
can we use this system front steering ( TWO WHEELS ) trikes?
why not power the back tires with separate drive motors and still have reverse, no slippage and more torque
Good point.
Simpler to build too.
Then you get to keep both adjustable rear hubs and mount the motor to the pedal area or sproket. Now you got a transmission and low gear for hills.
Backing up not that important to me.
twice the cost, half the distance unless you double the battery and twice the complexity - but that's what i think - go with what you think is right
@@ThinkingandTinkering you could use less powerful motors and still use the same power consumption for minimal cost difference. but that is just a thought for redundancy and less complication for those without a welder.
if we use two motors then how will change the power of both ,we can synchronize them which will work for straight movement but what about turning problem??? you would need to decrease power in one motor while turining
@@avisingh7641 an electric motor will free weel on a corner and the other will slow and take more load.
Try it and you will see what I mean.
Good stuff 👏
ingenious - will it " runaway" going down hill?
like this it would mate
@@ThinkingandTinkering Is there room for KERS braking?
Where can I find that axle shaft??
interessting, i have a reverse tricycle... i wanna make it to a quad.... cut the backwheel....what would yours cost??
Modern high performance motorcycles often have two discs for braking, there is a valve body that the lines attach to, so that the master cylinder activated applies equal pressure to both slave cylinders at the same time. I forget what the part is called, in an automobile it is called a metering valve, I think. Its mounted to the frame rail of the auto chassis, near the main cross member that holds up the transmission. It's not a serviceable part.
That’s cool, a couple more steps and you could make an independent rear suspension for a quad.
cool, now someone attach a 6" Rhombic drive Stirling engine to that axal with a paint on heater end, & vacuum flask cold end in the right orientation, + mostly magnetic Stirling cycled copper coiled heads+ magnets+ caps to feed the encased heater, call it good as a base low energy input amplifying device to be optimised ^_~
Cool idea
Where did you get the axel from
What is puzzling is that since the wheels can move freely forward with the axle not moving you essentially cannot brake by stopping the axle. Only whay i can think is having independant brakes in each wheel . Am i missing something?
Awesome idea
With your two freewheels.asyou explaind you cannot have a brake that works as is shown
i was trying to figure out how to make one. thank you.
do you have video of building a trike?
Glad I could help!
With this upgrade over lock differential, turning radius will be definitely improved by a significant amount
cheers mate
Where did you get the parts ?