If thats your car, please for god sake put the right size tyre on that rim. That was a rim that was to wide for that size tyre. Seems to be a 8 inch rim, with that specific tyre, the size is wrong, to much rim overhang. Rim placement in relation to the tyre beed placement directly effects sipe angle and scrubbing throung cornering.
This was one of your best videos of all time! I loved the presentation. Clearly, you spent a lot of time putting this together and I thank you very much for that.
@@Hambini I hope it made you feel good to know that I and many others clearly noticed the results of your great effort and appreciated it very much. 👏👏👏
Thanks for info. I’ve used golf club weights. Their basically short pieces of lead tape in 1g increments. Initially I stick on the rim like you taped the bolt. Then if I’m happy I break the wheel down and put them inside the rim tape. You’ll never get it perfect but get as close as possible but don’t let “better be the enemy of good”. On the rear wheel to bypass the free hub ratchet I take the chain off or slide it off and hang carefully on the stay.
I've done exactly the same. The tricky part is to adjust the weights after you've swapped tires.😁 I cut the led strips with scissors. Also mount the tire back the way it came off. If your tirres can mount in either direction (vittoria?) you're going to have to figure out which wasy it was.
@@jimhize On the rim tape! Or you use veloplugs. The weights come in quite narrow strips that even for 26mm wide rims fit right between the tubeless ridges. (I don't personally ride tubeless (compatible) tires which are supposedly a tighter fit.)
@@jimhize on or under the rim tape. Although the weights have their own adhesive I like under to make sure they stay in place. The downside mentioned is if you change tire or tube you may need to adjust the tape.
god damn the things i could have done in life if hambini had been my teacher in high school.. you're doing a great thing sharing your knowledge hambini. thanks heaps from all your viewers
Come for the sarcasm and PowerPoint roasts, stay for the next-level engineering analysis and detailing! One would suspect that more videos like this will push the bike biz to up its game with better product and marketing, but I don't think any such miracles will be forthcoming anytime soon.
Good stuff. I counter balance my wheel with lead tape on the rim bed, under rim tape. There are plenty of space there between tire seat on modern wide wheels. Most lead tape or tungsten tape for tuning tennis racket works. This won't impact aerodynamic and it's still easy to access (just under rim tape). As far as I see, it doesn't effect pumped up tire profile. In the past, I tend to under correct my wheel. Thinking reducing the amplitude is good enough and it weight less to reduce amplitude than to fully eliminate it. But since watching this video, I might revisit my setup and try to get very close to fully balance, if possible.
Great explanation on the difference between static and dynamic balancing, but also on the details on when it is needed. You are absolutely fantastic at explaining engineering principles; I have a physics degree and everything you explain is as good as any physics professor. Bravo.
This got me interested, so let's do some math from first principles: At 30 mph (48 kph), a weight at the edge of the wheel will experience (v^2/r) acceleration of ~50X gravity. So a 4 gram weight imbalance (Hambini's proposed limit) will "feel like" a ~6hz sinusoidal force with an amplitude of 200 grams, or a bit less than 1/2 a pound. One way to put this into context is to ask what size road bump that would 'feel like'. According to measurements in Silca's blog, a road bike tire has a load sensitivity of about 200 N/mm. Using these numbers, a 4g imbalance would feel the same as a ~0.01mm undulation in the road! (For context, that is about the size of a red blood cell and below the perceptual threshold of what you could feel with your hand in ideal conditions.) So, at least in the vertical plane, imbalance is fine on a bike wheel. However, we have to consider the horizontal plane as well. That 200g force is shaking a ~8kg bike, which is going to lead to an (a=f/m) acceleration of 0.025 m/s^2 (by 1/omega^2 math). This isn't a lot, and it's going to create a 6hz vibration of ~0.02mm assuming the rider wasn't providing any impediment to motion. That's only 2x the vertical case, and still nothing. Now all of this assumes no resonance. If the wheel imbalance was both undamped and operating near its resonant frequency (see video) then it could in theory produce large multiples of that displacement. But, I did the (w=sqrt(k/m)) math on a bunch of the subsystems and it's hard to see how resonance would be an issue at
@Dave As for the horizontal direction, the 8kg of the bike is only relevant for during the test, as Hambini was doing, with no rider on the bike. So yes, you see the bike shaking there quite a bit at high rpm (and that will happen with about any non-balanced wheel). Out on the road, of course you have to add the rider weight to that, so the effect will be about 10x lower then. Just saying/agreeing that wheel imbalance is typically not something to worry about, when the wheels are build (rim & spoke-ing) with any reasonable quality.
@@wouterdobbelaere yes follow thru to the end - the imbalance effect is more realized for lighter riders / I do balance my deep carbon rims (>40mm) using led tape if its slight and or epoxy a steel rod under the rim tape in the spoke hole
Good points there Dave. I agree. The movement is dependant on rider weight and tire softness also. But, add tubeless sealant to the mix and this miniscule vertical bobbing will probably dissapear as the fluid will disperse to cancel this. (at least when riding a perfectly flat surface that will never happen on the road)
Excellent info. As a junior, I balanced my wheels and my friends laughed at me. I didn't have any tools to demonstrate it was a good idea; it was just intuitive. I have been vindicated.
I really like bicycles and the content you offer is very interesting, sometimes because of my lack of knowledge in mathematics I don't understand, but I try to learn.. I'm from Brazil.. now it's 9 pm here and it's 30° C/86°F.. rain and cold is not the problem here.. I always prefer to ride at night because of the heat.. Thanks for teaching me such specific things about bikes..
A great video, thanks Hambini! I hadn't realised how much vibration there can be due to wheel imbalance. I've just experimented with my tubeless wheels/tyres (30mm rear and 25mm front Goodyear Eagle F1 tubeless tyres on Zeal Camerigg 44 wheels) on an upturned bike; without any "balancing weights", spinning up the rear really had the bike moving. I've taped a small washer to the spoke-face of the rim opposite the valve, using gaffer-tape, the difference is amazing. I'm looking forward to trialling this on the road - if it's as good as I think it will be, I'll probably be able to use stick-on golf club weights to balance.
OMG he is talking about this! I have deep carbon wheels with 60mm valve stems latex tubes. I bought a cheap photo speed gun and used a router motor to spin my wheels up to 35mph. There was a significant hop caused by the valve stem. So on the opposite side I used a 1/2 ounce crimp on fishing weight. Now both wheels are as smooth as silk at and speed. I’ve noticed on my rides that it’s way smoother all around and holds a 20+mph speed easier .
Yep - I had a pair of FFWD Tyro Dark 45mm Carbon wheels. Ended up adding 9g to balance these. Used sticky 3gram golf club weights inside the tyre so all neatly hidden. Transformed the handling of the bike.
Love Your Ritchey Logic Light Steel bike! Own a 1987 Bianchi Limited Ultegra 600 Down tube Shifters with 7 speeds, Rainbow Edition. Rides fast in classic comfort!
Applied as suggested and this works great. I used washers stacked up rather than a bolt, and a thick duck tape as I think an insulation tape will wear through on the road.
you can use something like bostik blu tack and put it on the outside of your wheel at height of your inner tube to determin the weight needed and finetune it until you have the correct weight &place. This way you won't need to take of you tire every time you need a correction. If it's balanced then replace it with the same weigth of golf club lead tape strip on the inside of the rim at the same place.
Great video! The way I do mine is : 1. Start adding bluetack to the inside of the wheel, until the wheel stops wobbling. 2. Weight the total amount of bluetack 3. Get the weights used for golf ... errmm stick and match the weight of the bluetack 4. Stick the golf weight to the wheel 5. Cover it with a strong gaffer tape to make it as flat as possible. The difference in the vibration is particularly noticeable when riding downhill on a very smooth surface. I balance both shallow aluminium and deeper carbon wheels this way.
Great video, cheers Hambini. You can use a motorcycle wheel balancer on a bicycle wheel with a thru axle. The wheel balancer is basically a stand with 2 sets of bearings either side and you place an axle through the wheel and put it onto the bearings and spin, heaviest parts sits on the bottom. Works perfectly, more accurate than leaving wheel in frame.
nobody mastered the absolutely jarring hard cut to bright orange like Hambini. Up there with the bone/space transition of 2001 space odyssey, will be studied by film students for years
As a professional engineer, albeit not mechanical, and bicycling enthusiast, I appreciate the technically-based insight into the various bicycle maladies that you address and the exposure of wanketeering and marketing misinformation.
After watching many Hambini videos: turn my volume down -> "hello Hambini fans!" ->then turn volume back up. Today: hmm something about Skillshare -> turn volume back up -> "HELLO, HAMBINI FANS!!!" :)
Outstanding. Thank you again for explaining the engineering in a way my hairdresser would master. Blinding case of the obvious a wheel needs balancing and totally ignored. Makes me now wonder on manufacturing consistency between wheel sets of the same model.
Yes!! I got a massive Speed Wobble at about 50 km/h from some very bad Newmen wheels on a Cube bike. The imbalance was huge and the bike was totally out of control and I nearly crashed. Sadly neither Newmen or Cube showed any interest in any possible faulty manufacturing. So typical.
I've just fitted a Shimano RS500 wheelset, they have a counterweight built into the rim opposite side to the valve which I thought was a nice touch. Rarely see that!
Hi I've been balancing my wheels for years. Alu wheels are heaviest opposite the valve hole while carbon wheels are heaviest at the valve hole. To balance them I use thin lead strips, used for anchoring aquarium plants, underneath the rim tape. I leave the wheel very slightly out of balance so when installing the tube and tyre the wheel is brought back into balance.
@@Paul58069 Hi Paul. Then it's the innertube causing that. Alu/Steel rims start straight then made into a hoop. The hoop is joined, pinned and welded which adds material and so weight. A valve hole is drilled opposite which removes material and decreases weight. I always balance my Alu wheels without tyres and tubes. I add lead strips either side of the valve hole , under the rim tape. I leave it slightly unbalanced because the extra weight of the innertube valve, and the valve lock ring brings it into balance.
Really dig the Hambini coveralls! I run tubeless hunt 30's and Reynolds arx 41's, I use the shortest valve stem possible and use black tungsten golf weight's and I balance them in hand with the thru axels which gets them really close. Just piece of mind when descending at speed, I no longer feel the wheel vibration.
Frenchie ! This better be good as I consider myself a wheel balancing expert. Not bad. I myself use solder wire and wrap it around the spoke very tightly (and a spot of epoxy on the ends to secure it) to balance my wheels. I don't do it in one spot 180 degrees off the heavy spot though. I do it in two spots 120 degrees off the heavy. I also eliminate the ratchet at the rear for more acurate placement of the weights. The average ham & egg'er has no idea how out of balance their wheels are. I tell them to put the bike in a work stand and get a wheel spinning and see what happens. When they do they can't believe how much movement there is. Balancing also reduces stresses to the bike, not just the rider. FTP Finn
pancho, I started balancing my wheels using my dad's plumbing solder as you described when I was a kid. It was very easy to balance a wheel by trial and error without knowing anything about the physics of the problem.
I have a pair of wheels that I could feel where imbalanced when riding. It was very noticeable on the beautifully smooth roads in Majorca when coasting downhill. It was less noticeable when pedalling or on rougher roads. I never had this problem with aluminium rims, so I reasoned it might be that the carbon rims were so light that the extra weight of the valve stem had proportionally more effect. I balanced them by bending some lead flashing around the rim and taping it down with electricians tape. I span the wheels in the frame and put the weight in the 12 o'clock position directly opposite the point of the rim that stopped lowest. That was opposite the valve stem, as expected. I kept altering the weight until the wheel no longer stopped spinning with the valve at the 6 o'clock position. I also found I could feel balance/imbalance by taking the wheel out of the frame and spinning while holding the ends of the QR. It just about worked. A while later I beautified it by replacing the lead flashing with lead strips for balancing golf clubs.
I put some weighted beads in my motorcycle tires, they dynamically balance the tire, works really well. Could Sealant if your tubeless, kind of do the same thing I wonder? Have you heard of these dynamic balancing beads? It's basically just a bunch (of course you measure) of weighted (ball bearings if you will) that find the trueing spot once rotating. Thanks for your videos, always insightful!
Hmm .. I've never been bothered by 'road buzz' or vibration from my wheels. Im 75kg and do many fast descents 80kph+. I did always wonder why the bike vibrates on the stand when spinning up the rear wheel though. Cheers for the info!!
Ironically is sent my Campagnolo Boras (tubs) back to Campagnolo Italy because they were the most out of balance set of wheels I’d ever ridden. Sadly the bike shop removed the tubs and cassette etc so consequently Campagnolo returned them with No Fault Found. It’s incredible that I’ve had to add so much weight to balance these rims, I might just as well have purchased a heavier set in the first place 🤷♂️
I started balancing my rims about three years ago just to get rid of road buzz and don't ride anywhere near 37kph. 4gr does make a difference even if it's within an ISO acceptable value.
An idea. Cut out the valve out of an inner tube exactly the same as you would normally use. Remove as much inner tube from valve as possible, weigh valve and valve cap. Then get a screw or screws of the same weight or slightly higher that have slots in the body, put slot over spoke and tighten with bolt.
I have the opposite with my aluminium DT Swiss spline p800 Training wheels the valve side needs a weight to balance the wheel. Must be a weld opposite the valve.
My situation is a bit different. At 110kg, 140rpm going downhill on a track bike, the imbalance is mainly caused by the stones on the saddle!. The suspension is the rider. Forget the wheels, A balance shaft is needed to correct crank inertia forces. You can see the serpentine path of tires after riding through a puddle. Still balanced wheels can't hurt.
I had a friend sniff off a 1 inch piece of a metal coat hanger, file the end so they’re nice and round, and put some electrical tape on it then tape it exactly opposite on the inside of the rim. He would do it on top of the rim tape. This would affectively counterweight the valve stem and there would be no sharp edges to puncture the tube. Manufactures could also solve this by adding a tiny bit of material buildup opposite of the Valve hole.
Looking at the cadence at which you get a resonant vibration I suspect you would only provoke this during fast descending. This is also when some bikes get speed wobble/tank slap so I think it makes a lot of sense that speed wobble may be triggered by an imbalanced wheel. I’ve had it twice while descending at 65kph+ on deep section lightweight wheels and it is bloody terrifying. I’ll certainly be looking at balancing my wheels.
It has been my experience that imbalanced wheels and rim brakes that touch on one side earlier than the other can cause it. When under load, shorter stems (under 90mm) seem to induce it when sprinting. My TCR had these issues in spades and had all three of those factors at one point or another, scary stuff that really kills your confidence in handling and putting down power.
@@paddychamp6069 never had it on the flat (but I’m not exactly a sprinter 😁). I could probably cope with that but I still get cold sweats about having it on a fast descent with a rapidly approaching blind hairpin. 😱
@@nstrug yeah, that's a real pickle to be in for sure! These days I run discs and a 120mm stem, but haven't balanced my wheels on my newest bike. I used to have blu-tac stuck onto the rims of my old bike, it was hideous, but worked a treat! There's actually a park tool video on wheel balancing where they use two bearings to support the wheel axle and it allows them to get a really precise heavy spot location, might be a helpful stopover on the way to getting your wheels set right.
Very informative - thanks! Two questions though... should I wear safety goggles if I plan to exceed 37kph and will the tape affect the grip of the tyre?
If someone wants to balance their wheel, may be they could stick wilson tungsten tape inside the rim (before inner tube). You can either balance the rim itself and accept that the tyre may cause other imbalance or mark the position , crack open the tyre, stick the weight and refit the tyre…
Hi Hambini! I run tubeless which means 30g of stuff sloshing around at speed in a narrow road bike tyre... that sounds quite significant in the context of the 4g of balance. How would you take the liquid into account with this approach. And does it have a dampening effect bc it's a liquid..?
Just my reasoning: The liquid will get dispersed inside the tyre. with more of it on the bottom due to gravity. The distribution of the liquid will remain fairly constant though, certianly at constant speeds. This means the liquid's center of mass is static with respect to the bike frame. Therefore, my guess would be the liquid has very little influence on the balance of the wheel,.
When i was a mechanic i have some doubts about where the líquid goes, i run some experiments, if u accelerate very Quick from dead stop the centrifugal force will keep the líquid in one Spot, but if u accelerate slowly the líquid will distribute more evenly
When I've done spin tests with sealant in my own tires, the imbalance is usually higher at first, and after a few seconds really drops off, indicating that the sealant always spins out and distributes around the tire. Also, when I've had flat tires and done a quick tire removal, the sealant appears to be spread pretty evenly out, wetting all the interior surface. Based on my observations I don't think there is much imbalance from sealant as it seems to distribute evenly from the variety of forces.
I remember dicking around with balancing tubular wheels 45 years ago, and eventually deciding with my road-racing friends, that any effects were inconsequential. Haven't bothered, since.
Note: the AUDI was just a random car he found outside and the police are looking for a 5yo in overalls for loitering and talking shit about other children’s manufacturing tolerances.
@@raufus sorry, i actually wrote that before he did the powerpoint. My bad. Got on a speed wobble last sunday ride. Was just too excited about having it explained.
you can use weights that you can buy in small packets from a golf shop, friend of mine just did this to his own wheels. he put them inside under the rim tape. they work great
Another thing to consider is if you have a stripped down rim, the hole where the valve comes out is missing material. Therefore has lost weight in that section of the rim. Then you put a valve stem on the same side and it replaces the weight although possibly more than the weight of the material that is missing. The question is, if you take out 3 g of material, does the valve weigh 3 g canceling each other out. I am sure the valve weighs more than the missing material. The question is, how much? If the net loss or gain is zero then there should be no imbalance
l'm getting new wheels and atm l ride pretty old mavic ksyriums ... weight is 60-65 kg but l've never had speed wobble or vibrations. gonna look out for that on my new carbon wheels tho
Hi Hambini. On a static balance do you know what average speed this would start effecting a rider ? I average 17 to 21 mph. I do rider faster when I’m trying to catch my hairdresser. Thankyou
mechanics language or in layman circles known as cussing disappeared and now we got skillshare. I actually enjoyed your vidjos as they were. very good to see usage of PPE aka AvE bible. it's the way to go, but please don't loose your soul to sponsors.
With all the static mass constraining the system, would you even be able to feel the wheel imbalance? I think we can agree that slow speeds this is irrelevant, but at faster speeds like on a descent: Each 1gram of imbalance, at the wheel circumference (.34m), at 72kph, is exerting 1.25N (edited my arithmetic error see below) of force on the axle. A 100kg bike+rider constraining the system about 490N per axle. Unless your wheel is out of balance by hundreds of grams, I can't see how you could feel any effect from the imbalance, compared to the bumps of the road and pedaling forces.
The circumference of a road bicycle wheel is not 0.34m. Not sure how you got 0.00125 N. Here's a link to a video that explains the math a bit more. th-cam.com/video/FubJV2N9dyY/w-d-xo.html
@@galenkehler Yeah. Your post was unclear what you were referring to by .34m Now that's sorted, I believe the equation would be: .001 kg * 0.34m * ((72kph / 3.6) / 0.34m )^2 And that would give you around 1.2 N
@@se7enTse7en good catch, sorry I made an arithmetic error. I still think the forces involved are so small compared to the random occilations from the road surface that balancing the wheel isn't going to be perceptible unless the wheel is very poorly made.
So what is the most recommended laymans solution? just lay down short strips of tape on the inside of the rim opp the heavy side with some small weight under the tape? Great video i didnt even know people balanced bicycle rims but I have Hypers also and when my bike is upside down and wheel spun as per ur demo it hops about also 😬
Go to a golf shop and buy a roll of lead tape and adhere it to the top of the rim opposite of the heavy spot in the wheel. Layer that lead tape up until it's perfect.
Hey there Hambini- Great video. I really get a lot from these educational ones. You mention a potential loss of 12w on a bad day while Silca in their aero wheel weight marketing suggest a possible gain of 1w at 30kph. Is this a matter of your figure being based in higher speed and imbalance or do you think there's some part of the situation they're missing? Maybe they're only counting hysteresis losses from tyre loads rather than frame/rider losses?
There is a bit more on it here and in much more detail www.hambini.com/an-engineering-guide-to-bicycle-wheel-balancing/ I guess the key thing to note here is I've used an official ISO standard, so it's recognized and has gone under fairly robust scrutiny. The silca methodology hasn't and I'm not saying it's wrong but there is no real technical scrutiny behind it. If you park all of that to one side, the other key point is the effect of resonance. That will have a dramatic impact on the power loss, if you ride the bike at a speed which causes resonance then the power loss will go up quite dramatically and that is what the chart shows. Typically resonant frequencies on a bike are at speeds above 35kph. and most of the time above 40km/h - hence the guidance for trigger speed to balance at 37ish KPH. If you are not riding at a resonant speed then the power loss will be only a few watts. The majority of the power loss when the thing vibrates happens due to flexing of items, the flexing is an energy loss as you never get back what you put in. A sort of side effect is the impact it will have on the body, physiologically people will not put as much power down if the bike is vibrating. I hope that helps.
Thanks so much for taking the time to reply- I've gone through the extended doc and with your explanation here it makes a lot more sense. Very keen to have a crack at it as soon as possible. As an aside I think a video explaining what effects lateral stiffness actually have on power loss at the rear wheel could be hugely valuable. I can't think of an area of bike design that attracts quite so much quackery (springy returning energy smoothing out dead spots in stroke, planing, whatever Jan Heine and co are into) yet has such a small amount of solid information/debunk/explanation of fundamentals out there. It's a real wasteland- if only there was a 5 year old with newly improved excel visualisation skills who could shine a light down for us plebs
Great videos Hambini!!! I love the Bottom Bracket I bought from you! How often should I repack the bearings on it, I always ride in clean dry conditions. Thanks. :)
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The first 1,000 people to use this link will get a 1 month free trial of Skillshare: skl.sh/hambini03221
Thanks, I decided to learn more about hairdressing
Keep this up and you could offer a course in bicycle engineering. I'd certainly take it.
Hambini time!!
If thats your car, please for god sake put the right size tyre on that rim. That was a rim that was to wide for that size tyre. Seems to be a 8 inch rim, with that specific tyre, the size is wrong, to much rim overhang. Rim placement in relation to the tyre beed placement directly effects sipe angle and scrubbing throung cornering.
This was one of your best videos of all time! I loved the presentation. Clearly, you spent a lot of time putting this together and I thank you very much for that.
It did take me quite some time.
@@Hambini I hope it made you feel good to know that I and many others clearly noticed the results of your great effort and appreciated it very much. 👏👏👏
Thanks for info. I’ve used golf club weights. Their basically short pieces of lead tape in 1g increments. Initially I stick on the rim like you taped the bolt. Then if I’m happy I break the wheel down and put them inside the rim tape. You’ll never get it perfect but get as close as possible but don’t let “better be the enemy of good”. On the rear wheel to bypass the free hub ratchet I take the chain off or slide it off and hang carefully on the stay.
I use the same lead tape. But it's even easier to just take the wheel off and hold it from the QR 😀
I've done exactly the same. The tricky part is to adjust the weights after you've swapped tires.😁 I cut the led strips with scissors. Also mount the tire back the way it came off. If your tirres can mount in either direction (vittoria?) you're going to have to figure out which wasy it was.
Doesn’t putting it under the rim tape make it difficult to mount a tyre?
@@jimhize On the rim tape! Or you use veloplugs. The weights come in quite narrow strips that even for 26mm wide rims fit right between the tubeless ridges. (I don't personally ride tubeless (compatible) tires which are supposedly a tighter fit.)
@@jimhize on or under the rim tape. Although the weights have their own adhesive I like under to make sure they stay in place. The downside mentioned is if you change tire or tube you may need to adjust the tape.
god damn the things i could have done in life if hambini had been my teacher in high school.. you're doing a great thing sharing your knowledge hambini. thanks heaps from all your viewers
I may have taken a great interest in hair dressers if he was my teacher ;)
Come for the sarcasm and PowerPoint roasts, stay for the next-level engineering analysis and detailing! One would suspect that more videos like this will push the bike biz to up its game with better product and marketing, but I don't think any such miracles will be forthcoming anytime soon.
Atleast we would become sound buyers
Good stuff.
I counter balance my wheel with lead tape on the rim bed, under rim tape. There are plenty of space there between tire seat on modern wide wheels. Most lead tape or tungsten tape for tuning tennis racket works.
This won't impact aerodynamic and it's still easy to access (just under rim tape). As far as I see, it doesn't effect pumped up tire profile.
In the past, I tend to under correct my wheel. Thinking reducing the amplitude is good enough and it weight less to reduce amplitude than to fully eliminate it. But since watching this video, I might revisit my setup and try to get very close to fully balance, if possible.
Great explanation on the difference between static and dynamic balancing, but also on the details on when it is needed. You are absolutely fantastic at explaining engineering principles; I have a physics degree and everything you explain is as good as any physics professor. Bravo.
This got me interested, so let's do some math from first principles: At 30 mph (48 kph), a weight at the edge of the wheel will experience (v^2/r) acceleration of ~50X gravity. So a 4 gram weight imbalance (Hambini's proposed limit) will "feel like" a ~6hz sinusoidal force with an amplitude of 200 grams, or a bit less than 1/2 a pound. One way to put this into context is to ask what size road bump that would 'feel like'. According to measurements in Silca's blog, a road bike tire has a load sensitivity of about 200 N/mm. Using these numbers, a 4g imbalance would feel the same as a ~0.01mm undulation in the road! (For context, that is about the size of a red blood cell and below the perceptual threshold of what you could feel with your hand in ideal conditions.)
So, at least in the vertical plane, imbalance is fine on a bike wheel. However, we have to consider the horizontal plane as well. That 200g force is shaking a ~8kg bike, which is going to lead to an (a=f/m) acceleration of 0.025 m/s^2 (by 1/omega^2 math). This isn't a lot, and it's going to create a 6hz vibration of ~0.02mm assuming the rider wasn't providing any impediment to motion. That's only 2x the vertical case, and still nothing.
Now all of this assumes no resonance. If the wheel imbalance was both undamped and operating near its resonant frequency (see video) then it could in theory produce large multiples of that displacement. But, I did the (w=sqrt(k/m)) math on a bunch of the subsystems and it's hard to see how resonance would be an issue at
@Dave As for the horizontal direction, the 8kg of the bike is only relevant for during the test, as Hambini was doing, with no rider on the bike. So yes, you see the bike shaking there quite a bit at high rpm (and that will happen with about any non-balanced wheel). Out on the road, of course you have to add the rider weight to that, so the effect will be about 10x lower then. Just saying/agreeing that wheel imbalance is typically not something to worry about, when the wheels are build (rim & spoke-ing) with any reasonable quality.
@@wouterdobbelaere yes follow thru to the end - the imbalance effect is more realized for lighter riders / I do balance my deep carbon rims (>40mm) using led tape if its slight and or epoxy a steel rod under the rim tape in the spoke hole
Good points there Dave. I agree. The movement is dependant on rider weight and tire softness also. But, add tubeless sealant to the mix and this miniscule vertical bobbing will probably dissapear as the fluid will disperse to cancel this. (at least when riding a perfectly flat surface that will never happen on the road)
its very detectable and at less than 30mph.
That bolt is 10 times the weight I expected you would need. That is amazing really
yea. weird
I’ve been living with speed wobbles on and off since the 90s. This is a game changer, cheers professor! 🍻
Excellent info. As a junior, I balanced my wheels and my friends laughed at me. I didn't have any tools to demonstrate it was a good idea; it was just intuitive. I have been vindicated.
I really like bicycles and the content you offer is very interesting, sometimes because of my lack of knowledge in mathematics I don't understand, but I try to learn.. I'm from Brazil.. now it's 9 pm here and it's 30° C/86°F.. rain and cold is not the problem here.. I always prefer to ride at night because of the heat.. Thanks for teaching me such specific things about bikes..
You are the The Workshop for bicycle world. Thank you for spitting facts
Glad to see you're coming around to review wheel balance. My offer still stands. Dan
A great video, thanks Hambini! I hadn't realised how much vibration there can be due to wheel imbalance. I've just experimented with my tubeless wheels/tyres (30mm rear and 25mm front Goodyear Eagle F1 tubeless tyres on Zeal Camerigg 44 wheels) on an upturned bike; without any "balancing weights", spinning up the rear really had the bike moving. I've taped a small washer to the spoke-face of the rim opposite the valve, using gaffer-tape, the difference is amazing. I'm looking forward to trialling this on the road - if it's as good as I think it will be, I'll probably be able to use stick-on golf club weights to balance.
I also wish i had a teacher, any teacher, who had cared about learning/teaching.. thankyou MISTER Hambini!
OMG he is talking about this! I have deep carbon wheels with 60mm valve stems latex tubes. I bought a cheap photo speed gun and used a router motor to spin my wheels up to 35mph. There was a significant hop caused by the valve stem.
So on the opposite side I used a 1/2 ounce crimp on fishing weight. Now both wheels are as smooth as silk at and speed. I’ve noticed on my rides that it’s way smoother all around and holds a 20+mph speed easier .
Yep - I had a pair of FFWD Tyro Dark 45mm Carbon wheels. Ended up adding 9g to balance these. Used sticky 3gram golf club weights inside the tyre so all neatly hidden. Transformed the handling of the bike.
Used it to balance my checkbook. Cheers!
Love Your Ritchey Logic Light Steel bike!
Own a 1987 Bianchi Limited Ultegra 600 Down tube Shifters with 7 speeds, Rainbow Edition.
Rides fast in classic comfort!
Hambini , congrats on the quality of your work in your videos !
Applied as suggested and this works great.
I used washers stacked up rather than a bolt, and a thick duck tape as I think an insulation tape will wear through on the road.
Excellent video. Woh! Those Excel skills! I was expecting to see a Hambini fix at the end though, so I’ll give the 5 year old an 8/10.
you can use something like bostik blu tack and put it on the outside of your wheel at height of your inner tube to determin the weight needed and finetune it until you have the correct weight &place. This way you won't need to take of you tire every time you need a correction. If it's balanced then replace it with the same weigth of golf club lead tape strip on the inside of the rim at the same place.
Great video!
The way I do mine is :
1. Start adding bluetack to the inside of the wheel, until the wheel stops wobbling.
2. Weight the total amount of bluetack
3. Get the weights used for golf ... errmm stick and match the weight of the bluetack
4. Stick the golf weight to the wheel
5. Cover it with a strong gaffer tape to make it as flat as possible.
The difference in the vibration is particularly noticeable when riding downhill on a very smooth surface.
I balance both shallow aluminium and deeper carbon wheels this way.
Great video, cheers Hambini. You can use a motorcycle wheel balancer on a bicycle wheel with a thru axle. The wheel balancer is basically a stand with 2 sets of bearings either side and you place an axle through the wheel and put it onto the bearings and spin, heaviest parts sits on the bottom. Works perfectly, more accurate than leaving wheel in frame.
nobody mastered the absolutely jarring hard cut to bright orange like Hambini. Up there with the bone/space transition of 2001 space odyssey, will be studied by film students for years
thanks for showing us COS vs SIN graphs!
Hot damn Hambini! Once again hitting it out of the park. Thanks man!
Oh and quite stoked that the pen is working quite well the past couple of days😂
Sounds great thanks one wheel is worse by a lot and it looks like it is the tire so I’ll change front to back tires only to check
yes. me weekly dosage of pure engineering ! Thanks!
i love you hambini, a true artist
As a professional engineer, albeit not mechanical, and bicycling enthusiast, I appreciate the technically-based insight into the various bicycle maladies that you address and the exposure of wanketeering and marketing misinformation.
After watching many Hambini videos: turn my volume down -> "hello Hambini fans!" ->then turn volume back up. Today: hmm something about Skillshare -> turn volume back up -> "HELLO, HAMBINI FANS!!!" :)
Outstanding. Thank you again for explaining the engineering in a way my hairdresser would master. Blinding case of the obvious a wheel needs balancing and totally ignored. Makes me now wonder on manufacturing consistency between wheel sets of the same model.
nothing like a bit of instruction and inspiration to kill a few hours with the bike, a roll of sticky-back lead tape and the kitchen scales 👏
Yes!! I got a massive Speed Wobble at about 50 km/h from some very bad Newmen wheels on a Cube bike. The imbalance was huge and the bike was totally out of control and I nearly crashed. Sadly neither Newmen or Cube showed any interest in any possible faulty manufacturing. So typical.
branded overall - you've made it!
I've just fitted a Shimano RS500 wheelset, they have a counterweight built into the rim opposite side to the valve which I thought was a nice touch. Rarely see that!
Hi I've been balancing my wheels for years. Alu wheels are heaviest opposite the valve hole while carbon wheels are heaviest at the valve hole. To balance them I use thin lead strips, used for anchoring aquarium plants, underneath the rim tape. I leave the wheel very slightly out of balance so when installing the tube and tyre the wheel is brought back into balance.
What you were supposed to get out of this vidya was that you've been wasting your time and money for years.
@@AnttiBrax Hi Antti....... Not really. I've descended mountains at over 85 kph and the bike has felt super stable compared to unbalanced wheels.
Thanks Steve, was lookin for examples of real world application - not found above
Steve, I only have alu rims and steel ones and my experience is that they are always heavy at the valve hole (with innertube installed)
@@Paul58069 Hi Paul. Then it's the innertube causing that. Alu/Steel rims start straight then made into a hoop. The hoop is joined, pinned and welded which adds material and so weight. A valve hole is drilled opposite which removes material and decreases weight. I always balance my Alu wheels without tyres and tubes. I add lead strips either side of the valve hole , under the rim tape. I leave it slightly unbalanced because the extra weight of the innertube valve, and the valve lock ring brings it into balance.
Really dig the Hambini coveralls! I run tubeless hunt 30's and Reynolds arx 41's, I use the shortest valve stem possible and use black tungsten golf weight's and I balance them in hand with the thru axels which gets them really close. Just piece of mind when descending at speed, I no longer feel the wheel vibration.
I have used lead tape for golf clubs on top of the rim tape under the tires a few years.
Hambini has grown up! 😃
Frenchie ! This better be good as I consider myself a wheel balancing expert.
Not bad. I myself use solder wire and wrap it around the spoke very tightly (and a spot of epoxy on the ends to secure it) to balance my wheels. I don't do it in one spot 180 degrees off the heavy spot though. I do it in two spots 120 degrees off the heavy. I also eliminate the ratchet at the rear for more acurate placement of the weights. The average ham & egg'er has no idea how out of balance their wheels are. I tell them to put the bike in a work stand and get a wheel spinning and see what happens. When they do they can't believe how much movement there is. Balancing also reduces stresses to the bike, not just the rider.
FTP
Finn
I thought removing the pawls/freewheel would make more sense.
pancho, I started balancing my wheels using my dad's plumbing solder as you described when I was a kid. It was very easy to balance a wheel by trial and error without knowing anything about the physics of the problem.
Great video on wheel balancing. Even I understood most of it.
Thanks for the Skillshare tip!
I have a pair of wheels that I could feel where imbalanced when riding. It was very noticeable on the beautifully smooth roads in Majorca when coasting downhill. It was less noticeable when pedalling or on rougher roads. I never had this problem with aluminium rims, so I reasoned it might be that the carbon rims were so light that the extra weight of the valve stem had proportionally more effect. I balanced them by bending some lead flashing around the rim and taping it down with electricians tape. I span the wheels in the frame and put the weight in the 12 o'clock position directly opposite the point of the rim that stopped lowest. That was opposite the valve stem, as expected. I kept altering the weight until the wheel no longer stopped spinning with the valve at the 6 o'clock position. I also found I could feel balance/imbalance by taking the wheel out of the frame and spinning while holding the ends of the QR. It just about worked. A while later I beautified it by replacing the lead flashing with lead strips for balancing golf clubs.
Very timely topic, as I've just put some SKS Airspy sensors on the bike and needed to counter balance the 18g added.
Job well done! Bravo!
Fascinating, great vid. My mark mark one chopper will be flying now😂.
Phase lag is related to gyroscopic precession, where an input to a rotating object will see the output after 90 degrees
Love it. Thanks for the education.. and entertainment 😀👍
Impresionante explicación, muchas gracias!
Voy a hacer eso con las ruedas de mi bicicleta de carretera.
I put some weighted beads in my motorcycle tires, they dynamically balance the tire, works really well. Could Sealant if your tubeless, kind of do the same thing I wonder? Have you heard of these dynamic balancing beads? It's basically just a bunch (of course you measure) of weighted (ball bearings if you will) that find the trueing spot once rotating. Thanks for your videos, always insightful!
Hmm .. I've never been bothered by 'road buzz' or vibration from my wheels. Im 75kg and do many fast descents 80kph+. I did always wonder why the bike vibrates on the stand when spinning up the rear wheel though. Cheers for the info!!
Spiffing explication. Again, I am shown how much I didn't known about yet another subject. Thanks, darling.
Ironically is sent my Campagnolo Boras (tubs) back to Campagnolo Italy because they were the most out of balance set of wheels I’d ever ridden. Sadly the bike shop removed the tubs and cassette etc so consequently Campagnolo returned them with No Fault Found. It’s incredible that I’ve had to add so much weight to balance these rims, I might just as well have purchased a heavier set in the first place 🤷♂️
I started balancing my rims about three years ago just to get rid of road buzz and don't ride anywhere near 37kph. 4gr does make a difference even if it's within an ISO acceptable value.
An idea.
Cut out the valve out of an inner tube exactly the same as you would normally use. Remove as much inner tube from valve as possible, weigh valve and valve cap. Then get a screw or screws of the same weight or slightly higher that have slots in the body, put slot over spoke and tighten with bolt.
I liked the prior hair dresser, the Mr Spock hair cut 🤣👍
I have the opposite with my aluminium DT Swiss spline p800 Training wheels the valve side needs a weight to balance the wheel. Must be a weld opposite the valve.
Nice AB's jersey bro!!!
My situation is a bit different. At 110kg, 140rpm going downhill on a track bike, the imbalance is mainly caused by the stones on the saddle!. The suspension is the rider. Forget the wheels, A balance shaft is needed to correct crank inertia forces. You can see the serpentine path of tires after riding through a puddle. Still balanced wheels can't hurt.
Very well made. When is your next live Q&A ? I love those.
Great Hambini
I had a friend sniff off a 1 inch piece of a metal coat hanger, file the end so they’re nice and round, and put some electrical tape on it then tape it exactly opposite on the inside of the rim. He would do it on top of the rim tape. This would affectively counterweight the valve stem and there would be no sharp edges to puncture the tube. Manufactures could also solve this by adding a tiny bit of material buildup opposite of the Valve hole.
love the educational videos
Good work well done Engineer Hambini 👍
If u have tubeless u can add the weight counterbalance under the tire Just like kushcore (inner tire foam).
That could help
Looking at the cadence at which you get a resonant vibration I suspect you would only provoke this during fast descending. This is also when some bikes get speed wobble/tank slap so I think it makes a lot of sense that speed wobble may be triggered by an imbalanced wheel. I’ve had it twice while descending at 65kph+ on deep section lightweight wheels and it is bloody terrifying. I’ll certainly be looking at balancing my wheels.
It has been my experience that imbalanced wheels and rim brakes that touch on one side earlier than the other can cause it.
When under load, shorter stems (under 90mm) seem to induce it when sprinting.
My TCR had these issues in spades and had all three of those factors at one point or another, scary stuff that really kills your confidence in handling and putting down power.
@@paddychamp6069 never had it on the flat (but I’m not exactly a sprinter 😁). I could probably cope with that but I still get cold sweats about having it on a fast descent with a rapidly approaching blind hairpin. 😱
@@nstrug yeah, that's a real pickle to be in for sure! These days I run discs and a 120mm stem, but haven't balanced my wheels on my newest bike.
I used to have blu-tac stuck onto the rims of my old bike, it was hideous, but worked a treat! There's actually a park tool video on wheel balancing where they use two bearings to support the wheel axle and it allows them to get a really precise heavy spot location, might be a helpful stopover on the way to getting your wheels set right.
@@paddychamp6069 I actually have a truing stand. Might get some of the Mariposa weighted stickies.
Very informative - thanks! Two questions though... should I wear safety goggles if I plan to exceed 37kph and will the tape affect the grip of the tyre?
You’re a genius
If someone wants to balance their wheel, may be they could stick wilson tungsten tape inside the rim (before inner tube).
You can either balance the rim itself and accept that the tyre may cause other imbalance or mark the position , crack open the tyre, stick the weight and refit the tyre…
Hi Hambini! I run tubeless which means 30g of stuff sloshing around at speed in a narrow road bike tyre... that sounds quite significant in the context of the 4g of balance. How would you take the liquid into account with this approach. And does it have a dampening effect bc it's a liquid..?
Good question.
Just my reasoning: The liquid will get dispersed inside the tyre. with more of it on the bottom due to gravity. The distribution of the liquid will remain fairly constant though, certianly at constant speeds. This means the liquid's center of mass is static with respect to the bike frame. Therefore, my guess would be the liquid has very little influence on the balance of the wheel,.
When i was a mechanic i have some doubts about where the líquid goes, i run some experiments, if u accelerate very Quick from dead stop the centrifugal force will keep the líquid in one Spot, but if u accelerate slowly the líquid will distribute more evenly
it will probably spread around the tire, how even it goes - nobody really knows as some of it ends up sealing small punctures
When I've done spin tests with sealant in my own tires, the imbalance is usually higher at first, and after a few seconds really drops off, indicating that the sealant always spins out and distributes around the tire.
Also, when I've had flat tires and done a quick tire removal, the sealant appears to be spread pretty evenly out, wetting all the interior surface.
Based on my observations I don't think there is much imbalance from sealant as it seems to distribute evenly from the variety of forces.
Good stuff, thankyou
I remember dicking around with balancing tubular wheels 45 years ago, and eventually deciding with my road-racing friends, that any effects were inconsequential. Haven't bothered, since.
Note: the AUDI was just a random car he found outside and the police are looking for a 5yo in overalls for loitering and talking shit about other children’s manufacturing tolerances.
totally random!
really interesting actually
Can you investigate how a speed wobble comes about? Thank you. Love your videos.
He already did in the video.
@@raufus sorry, i actually wrote that before he did the powerpoint. My bad. Got on a speed wobble last sunday ride. Was just too excited about having it explained.
@@jakebilbao Make sure your headset bearings have correct preload and no play.
Many things can cause it, but that one is a common contributing factor.
@@blooptastic thank you, i'll check it. Happened a few times already, always descending and me applying brakes. Rim brakes. Still editing the video.
Very informative, thank you. Have you any advice on how/what to use to imbalance wheels ? I'd like to do something for my front Hed jet wheel.
you can use weights that you can buy in small packets from a golf shop, friend of mine just did this to his own wheels. he put them inside under the rim tape. they work great
@@paulhowell7103 nice tip, thanks !
Another thing to consider is if you have a stripped down rim, the hole where the valve comes out is missing material. Therefore has lost weight in that section of the rim. Then you put a valve stem on the same side and it replaces the weight although possibly more than the weight of the material that is missing. The question is, if you take out 3 g of material, does the valve weigh 3 g canceling each other out. I am sure the valve weighs more than the missing material. The question is, how much? If the net loss or gain is zero then there should be no imbalance
l'm getting new wheels and atm l ride pretty old mavic ksyriums ... weight is 60-65 kg but l've never had speed wobble or vibrations. gonna look out for that on my new carbon wheels tho
For years I've used flattened airgun pellets stuck on with insulating tape!...usually 4 max. Takes up little space and seems to last
Prof Dr. Dr. h.c. Hambini ! Gruss aus Köln
Gruess Aus Ehrenfeld! EFFZEH
I balance using lead adhesive pads used on golf clubs.
Brilliant video. One problem...I'm my own hairdresser. Actually, that's not a problem at all now that I think about it...
Hi Hambini. On a static balance do you know what average speed this would start effecting a rider ? I average 17 to 21 mph. I do rider faster when I’m trying to catch my hairdresser. Thankyou
mechanics language or in layman circles known as cussing disappeared and now we got skillshare. I actually enjoyed your vidjos as they were. very good to see usage of PPE aka AvE bible. it's the way to go, but please don't loose your soul to sponsors.
all noted
With all the static mass constraining the system, would you even be able to feel the wheel imbalance? I think we can agree that slow speeds this is irrelevant, but at faster speeds like on a descent:
Each 1gram of imbalance, at the wheel circumference (.34m), at 72kph, is exerting 1.25N (edited my arithmetic error see below) of force on the axle.
A 100kg bike+rider constraining the system about 490N per axle.
Unless your wheel is out of balance by hundreds of grams, I can't see how you could feel any effect from the imbalance, compared to the bumps of the road and pedaling forces.
The circumference of a road bicycle wheel is not 0.34m.
Not sure how you got 0.00125 N.
Here's a link to a video that explains the math a bit more.
th-cam.com/video/FubJV2N9dyY/w-d-xo.html
@@se7enTse7en .34m is the approximate radius. Not sure where you're using the circumference.
@@galenkehler Yeah. Your post was unclear what you were referring to by .34m
Now that's sorted, I believe the equation would be:
.001 kg * 0.34m * ((72kph / 3.6) / 0.34m )^2
And that would give you around 1.2 N
@@se7enTse7en good catch, sorry I made an arithmetic error. I still think the forces involved are so small compared to the random occilations from the road surface that balancing the wheel isn't going to be perceptible unless the wheel is very poorly made.
My bike rides smoother at speed esp downhill when wheels are balanced.
I weigh 63 kg. Thank you!
Ohhh he's on the big ring! Let the intimidation begin !
Ill take that, I'm a dynamic cyclist, made my day, chuffed.
So what is the most recommended laymans solution? just lay down short strips of tape on the inside of the rim opp the heavy side with some small weight under the tape? Great video i didnt even know people balanced bicycle rims but I have Hypers also and when my bike is upside down and wheel spun as per ur demo it hops about also 😬
Go to a golf shop and buy a roll of lead tape and adhere it to the top of the rim opposite of the heavy spot in the wheel. Layer that lead tape up until it's perfect.
I'm finding cranks with peddles on are out of balance to you can put weights on crank arm.
Hey there Hambini- Great video. I really get a lot from these educational ones.
You mention a potential loss of 12w on a bad day while Silca in their aero wheel weight marketing suggest a possible gain of 1w at 30kph.
Is this a matter of your figure being based in higher speed and imbalance or do you think there's some part of the situation they're missing? Maybe they're only counting hysteresis losses from tyre loads rather than frame/rider losses?
There is a bit more on it here and in much more detail www.hambini.com/an-engineering-guide-to-bicycle-wheel-balancing/
I guess the key thing to note here is I've used an official ISO standard, so it's recognized and has gone under fairly robust scrutiny. The silca methodology hasn't and I'm not saying it's wrong but there is no real technical scrutiny behind it. If you park all of that to one side, the other key point is the effect of resonance. That will have a dramatic impact on the power loss, if you ride the bike at a speed which causes resonance then the power loss will go up quite dramatically and that is what the chart shows. Typically resonant frequencies on a bike are at speeds above 35kph. and most of the time above 40km/h - hence the guidance for trigger speed to balance at 37ish KPH. If you are not riding at a resonant speed then the power loss will be only a few watts.
The majority of the power loss when the thing vibrates happens due to flexing of items, the flexing is an energy loss as you never get back what you put in. A sort of side effect is the impact it will have on the body, physiologically people will not put as much power down if the bike is vibrating. I hope that helps.
Thanks so much for taking the time to reply- I've gone through the extended doc and with your explanation here it makes a lot more sense. Very keen to have a crack at it as soon as possible.
As an aside I think a video explaining what effects lateral stiffness actually have on power loss at the rear wheel could be hugely valuable. I can't think of an area of bike design that attracts quite so much quackery (springy returning energy smoothing out dead spots in stroke, planing, whatever Jan Heine and co are into) yet has such a small amount of solid information/debunk/explanation of fundamentals out there. It's a real wasteland- if only there was a 5 year old with newly improved excel visualisation skills who could shine a light down for us plebs
Great videos Hambini!!! I love the Bottom Bracket I bought from you! How often should I repack the bearings on it, I always ride in clean dry conditions. Thanks. :)
Nice shirt! 👍👏👏
That's a nice LOOKing bike.
On a serious note . You will sometimes find that wheel manufacturers will put the decals opposite the valve hole
It's because it looks better in photos. But I agree, marketing bikes is serious.
Rumour has that some put the pedals opposite of the valve hole.. Rgr