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Why Rotating Wheel Weight Doesn't Matter: A Real World Cycling Experiment

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Rotating weight on a bike's wheels, does it actually matter? Last year we made a video looking into the science behind heavy and light wheels for cycling, and it caused a bit of disagreement. Lots of fellow cyclists will tell you that you need lighter wheels because rotating weight is worth more than the static weight of the rest of your road bike. Ollie has come up with a simple real world test to see whether that is really the case.
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28 авг 2024

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Комментарии : 750

@gcntech 3 года назад

What do you think? Does rotating weight matter?

@nialltracey2599 3 года назад

If there is any positive effect, it's surely got to be on pedal stroke...? Rotating weight must surely slow acceleration under pedal power more than static weight as you've got to increase the rotational inertia more then on a lighter wheel to get to the same linear speed, but on the other hand, that inertia is going to carry you through top/bottom dead centre with less loss of speed, isn't it...?

@desertrainfrog1691 3 года назад

Pre-workout teddy grahams are all that matter. 😤

@PrzemyslawSliwinski 3 года назад

It pulls our legs anyway...

@scottb6341 3 года назад

Taking this idea to the next level create a test using weight and rotational weight with a power meter in a more real world situation. Have a short TT flat section and a hilly section and hold the same speed and see the differences in power needed to maintain speed with different arrangements of weight.

@Ed.R 3 года назад

No it doesn't matter, the only things that matter are those that convert pedalling energy into heat by friction (bearings, rolling resistance, braking) or movement of something other that the bike (air, soft ground). Same as weight of the bike doesn't matter as long as you never brake or only race up hill. Of course wheel weight and bike weight make a difference to the way the bike feels and in a way that matters.

@xxxpole 3 года назад

7:30 - pee into the water bottle, there will be no weight loss :)

@gcntech 3 года назад

😂 That's a risky option...

@jayhoughton4174 3 года назад

@@gcntech especially if you forget momentarily that you’ve done it 🤣🤣🤣

@retroonhisbikes 3 года назад

Bear grills style

@michalpollak4942 3 года назад

🤣👌🏽

@AbhishekMasne 3 года назад

Potential energy remains in the body . And when reached the lowest point, dispose it, by m1V1=m2V2 velocity should increase In theory

@GuilhermeSantos-uz8jd 3 года назад

The difference is in aceleration. Weight to the wheels means rotational inertia that is multiplied by speed and diameter sqare of the wheel. Weight to the frame is just normal inertia. Weight to the wheel affects aceleration way more, but it helps to keep top speed when you reach it

@eddiearimas2201 3 года назад

I experienced this and not a pro cyclist. And if they throw in the other factors like tubeless, tubular, latex and butyl tubes. Speed going downhill should increase slightly and the extra force in speed with less rolling resistance should get a greater distance. Before I got my aero wheels, my bike review mentioned would not be as fast as others going downhill. I truly think if can go tubeless in theory my rolling resistance should decrease and should be able to go farther due to more speed forcing the bike to go farther without peddling.

@jaspreetsidhu5708 3 года назад

Love it when ollie "drops" some knowledge.

@adamweb 3 года назад

Just a casual PhD in chemistry!

@jaimeb.7537 3 года назад

lol

@1234doodle 3 года назад

I think seeing the difference in acceleration would be more interesting. It would be cool if you could test two bikes that weigh the same i.e. a Canyon Ultimate Cf Sl with light wheels compared to a Ultimate CFR with deep wheels. If both bikes have the same geometry and weigh the same, only difference being the wheels, that would be interesting results.

@supernoodles908 3 года назад

You can just do some basic maths to calculate it. Simple angular momentum and acceleration. Basically it's bugger all

@DrunkieCat 3 года назад

Then the acceleration is the same, that's basic physics

@6speedtib 3 года назад

The inertia of the wheel with more weight using the formula for a hoop since most the weight is along the outside is I=MR^2 . Inertia is the resistance to motion, so if we add weight to the outside the resistance to motion increases. Therefor more weight on the outside of the wheel will mean the wheel accelerates slower with the same amount of power applied. NOOOW if we moved to a full disk wheel the formula changes to I= 1/2 MR^2 so if the wheel was the same mass as the one that was a hoop it would accelerate faster. That is assuming the mass is evenly spread across the wheel. This experiment primarily covered potential energy and energy conservation since they didn't apply any power themselves. (energy conservation = no outside forces). In short, It would be better to see them try this for acceleration but I also think human nature makes that hard to duplicate so we would almost want to see it with a motor applying 200 watts for x amount of seconds to get a real answer.

@supernoodles908 3 года назад

@@6speedtib again, you don't need to physically test it. The formulas say what it is

@shamuslamont100 3 года назад

@@supernoodles908 no. Formulas don't tell it all. Just like the theory (and even testing in a wind tunnel) with aero frames and wheels; real world testing does not derive the same results. After 200,000 km's of riding, I can assure you, rotational wheel weight makes a difference. It makes a difference in the overall feel of the bike, and can change how quickly you can accelerate and attack hills.

@antosbielli158 3 года назад

I found it quite clever to choose Ollie for a video that doesn't require any physical effort.

@06823834italia 3 года назад

This type of test doesn't highlight where the difference would be for rotating weight. It absolutely matters for accelerating, stopping, and even handling. Its because when doing any of those things you need to change not just the linear momentum, but the angular momentum as well. Now whether or not it matter enough for you to drop a ton of money of lightwheels is up to you haha.

@dpalmer8959 3 года назад

Agreed. If in a race you needed to accelerate to stay on a wheel or create a gap then rotating weight would be a very big deal.

@magnusdagbro8226 3 года назад

@@dpalmer8959 how much would you reckon? I mean how much more effort would it be to accelerate with 600g heavier wheels?

@nounours2627 3 года назад

@@dpalmer8959 There is no point in creating a gap if you can't maintain it because of the increased drag.

@CamiKite 2 года назад

@@magnusdagbro8226 Almost nothing! Consider a cyclist of 70 kg with a bike frame of 7 kg and heavy wheels of 2 kg. Accelerating from 30 km/h to 40 km/h in 5s represents an average power of 437W. With light wheels of 1.5 kg, the same accelaration requires 432W, that's only 5 less watts! And in reality it's even less because we have supposed that all the weight of the wheels is at the extremity

@dedybadharu2804 2 года назад

@@CamiKite what if the cyclist on the lighter wheel weight 70.5 kg or the bike frame 500 gr heavier..thus overall weight is the same.. would it make any diffrent?

@Dr.Schlitz 3 года назад

Add weight to wheelset without altering aerodynamics by adding latex sealant.

@lasselyhne-hansen9338 3 года назад

In that case my theory is that not all of the liquid would actually rotate :)

@kosskrit 3 года назад

@@lasselyhne-hansen9338 Exactly, that is a problem with tubeless setup. You have to overcome the resistance of sealant flowing through a tyre. The sealant is probably non-newtonian fluid and combine it with the inner geometry of a tyre, roughness of its surface and heating during ride and you have problem which is analytically really shitty to solve. You would have to do simulations in Fluent etc and I would like to know, how many companies (Maxxis, Continental...) made those before their marketing department started their campaign.

@imrekovacs3841 3 года назад

Agreed the rotating mass isn't so much an issue for more-or-less flat routes (with the exception of sprint/attack where lighter rotating mass is easier to accelerate); however, I would like to see an experiment to show just how much difference it makes for hill climbing...There should be a significant advantage for a lighter wheel (assuming aero qualities are the same) as climbing requires acceleration (varying with grade) to overcome the force of gravity. Many have commented on the physics of this already and it seems to me that this is at least an equally interesting and worthy experiment!

@betruly7894 3 года назад

Nice test. I replaced my both winter tire 1200g to summer tyre both weight 540g. I felt a noticeable acceleration from stand point. The bike felt lighter and more nervous. For me if one use light weight wheels this will help overall performance it changes the bike drastically.

@lasselyhne-hansen9338 3 года назад

I just changed my studded winter tires as well and it felt like a completely different bike - strava calculated the difference to 50W compared to a similar run. I think that rolling resistance also factors heavily in here though. But yea the best upgrade for your bike is definitely spring :)

@elianterelle2935 3 года назад

@@The86rick But isn't this the same with a heavier frame? When you accelerate it, you have to apply more force, but it also has a higher momentum compared to a lighter frame at the same speed, so it will also retain its speed longer.

@jiangheng 3 года назад

Even less valid than the first video...How about try adding weight to wheels in a crit race?

@TheraPi 3 года назад

Rotating weight has more effect on the sudden accelerations and attacks than on slow run-outs.

@lexistential 3 года назад

there are a couple of problems I see in real-world applications - this only works at marginal weight increases, because the power required to accelerate a wheel that weighs, for exaggerative purposes, 5kg more will substantially affect the rider's long term endurance. this problem arises from the premise assuming humans have infinite power to accelerate the wheel, or are starting at the top of a hill. even most "heavy" wheels are fairly light, but if a rider is accelerating many times (as in a crit), this will add up over time - the rolling resistance from the tire increases with mass, so doing the test with a much higher weight will increase friction (or again, add up the small increase over time for a very long track) and slow you down

@sdonalds123 3 года назад

in a race situation I can see the advantage of lower rotating mass to enable you to get into the back wheel of an attacking rider sooner and therefore get into the draft sooner, saving energy.

@duanedaylebaliatan5209 3 года назад

On a peleton I think weight kinda matters, it can be a difference between responding to an attack and grabbing their wheel early or not being able to grabe their wheel early and have to chase them down

@jamie152 3 года назад

oli 'science' bridgewood adds 600g of weights to a 600ml water bottle.. hmm water might of been a simpler alternative. :)

@lexistential 3 года назад

probably wouldnt matter for this experiment but using water adds an extra variable, whereas using the weights ensures you're adding the same mass to each run

@thepleasureroom9646 3 года назад

You can't attach water to a wheel 😆

@jamie152 3 года назад

i just meant he probably had a full water bottle that he #dropped to fill with weights.

@keirfarnum6811 3 года назад

What if one filled the wheels with water, and then pump air in to fill it out and get it up to pressure.

@serdiezv 3 года назад

@@lexistential not if you use a scale, 600g is 600g

@franklehmann426 3 года назад

One thing I learned is, that the deep section Zipp wheels are as aero as the shallow ones.

@kedarkulkarni3030 3 года назад

The perfect explaination 😂😂😂 Although, the weather conditions can affect as the sun was up during the aero wheels and hence increasing the temperature decreasing the density of air in turn affecting aerodynamics??? But this should mean that the shallow wheels are more aero😅

@TeoSluga 3 года назад

Exactly, or saying differently: the difference is negligable. One thing we learned here is that heavier bike descents better. That is something we all knew from skiing already. One needs to be heavy to go faster downhill...

@Alex-to8es 3 года назад

Most of these types of wheels are tested at 40-60kph where the marginal aerodynamic gains are far more obvious, there is however of course are reason most of the Pro Peloton aren't seen on them, and that is due to them catching cross winds and only marginally better if at all in the real world for aerodynamics.

@serdiezv 3 года назад

@@Alex-to8es exactly, you'd have to measure at peloton speed during a greater amount of time to get noticeable results

@albr4 3 года назад

he won't be going fast enough for the aerodynamics to make a big effect, the deep wheels will only be about 10 watts faster at this speed so it won't make a noticeable difference in a test like this. If he was going at a decent pace, like 30mph average on this descent/short ascent, he will save 45 watts using the deep wheels which would be a noticeable difference. Especially if you were doing a strava segment, TT, race. I can do 30mph with about 280 watts using 80mms wheels for 5 minutes, my FTP is about 255, doing 320 watts with shallow wheels means I would only be able to hold 30mph for 3 minutes. That's a gigantic difference.

@JaggoLee 3 года назад

10:16 I like that the dogs wear jackets that match their handlers.

@user-ov7sx5ur6u 3 года назад

Basic physics. The velocity and acceleration are two different thing. Lighter wheels will acceleration faster going up.

@user-ov7sx5ur6u 3 года назад

@Alright Alright Alright agree. Got my industrial operations engineering degree at U of M. Aka the best in the country. Leave it to me to do the math

@ianusna91 3 года назад

When I moved from Mavic Askium to Campy Bora One 35, I felt like the bearings made more of a performance change than the pure weight of the wheel. Yes the wheels were stiffer for more efficient power transfer and more aero but they also hold speed much better than the Askium, even with less stored kinetic energy due to weight. There are certainly point of diminishing returns for any modification. Would be interesting to see some focus on stock wheel and BB bearings versus different cost upgrades. Where is the inflection point point between cost and improvement.

@lucasklaassen135 3 года назад

Actually, this video proofs that rotating weight does make a sight difference. The more aero bike made it exactly as far as the non-aero bike, even though they were equally heavy. Of course, this test probably isn’t representative for every situation, like you said, but it is quite interesting still

@joaovictorgoncalves6217 3 года назад

Would be a Nice test to do the same wattage on a climb with the different weigh locations

@MichaelBoogerd 3 года назад

Probably screwed any result by having different levels of tuck on each run, CdA bigger variable than the slight weight added.

@future62 3 года назад

This was my first thought. They didn't control for variables at all.

@albr4 3 года назад

he got more and more aero each time lol

@roydarnell3683 3 года назад

@@future62 They NEVER do

@DaveShawMusic 3 года назад

I'd be interested to find out if it took less time to get to the same place with the 808s than the shallower wheels.

@wilfriedhuijbregts9828 3 года назад

No, not less time, more. The wheels are heavier, and since Ollie didn't pee, make up a bigger percentage of the mass of the system. So percentage wise a bigger part of gravitation is needed to spin up the wheels. So this causes less accelaration going downhill, but also less deceleration going up. So hé covers the same distance, but at lower pace.

@johnnybravo1912 3 года назад

It would be interesting if you did this experiment going uphill..

@S1zx6r 3 года назад

What this experiment also shows, is that it's often worth pedalling downhill.

@sjlacey65 3 года назад

Yep, adding more inertia by the added mass of my post Covid body weight looks like an advantage (up to a point.....)

@iamzoone 3 года назад

Same for HEV dish-like wheels. HEV can store energy in battery so gain benefit at start-stop situation, but no benefit in constant high speed. So they(manufacturer) use aero-wheels for HEVs which is benefitial in constant hight-speed situation.

@tomaszbaran 3 года назад

You could also try adding 300ml of sealant per wheel to distribute the weight more evenly :)

@tihs87 3 года назад

not really, approximately 250ml of that sealant would be sitting happily on the bottom of the tire for the whole ride, being a static mass with some extra friction.

@KenSmith-bv4si 3 года назад

I replaced the stock OEM flywheel(22lbs) on my 92 MX-5 with a lighter chrome moly flywheel 7lbs. Blipping on the down shifts was so much fun.

@Shadowboost 3 года назад

Two orders of magnitude difference in weight

@dedge12858 3 года назад

@@Shadowboost Umm, I think the new flywheel would need to be 0.22lbs to be 2 orders of magnitude lighter

@djrlloyd 3 года назад

In the words of Scotty “Yuh cana change the laws of physics Captain”

@bele13 3 года назад

I would hypothesize that a difference in the moment of inertia of the wheels makes the biggest difference not so much in hill climbing, which is dominated by the increase in potential energy, but in technical courses (e.g. crits), where you constantly have to accelerate and brake. 🤔

@JimKJeffries 3 года назад

There is the issue of unsprung energy, meaning the heavy wheel is not as responsive to directional changes. Perhaps I'm showing my fondness for suspension

@stuartfreedman6854 3 года назад

Remember that when you stand up on a climb, each pedal stroke is a tiny acceleration. Also worth mentioning is that when I have taken steps to lighten my wheels, even when adding a second water bottle, the bike just plain feels better. Not the most scientific, but true nevertheless. Interesting vid though. Keep 'em coming.

@roydarnell3683 3 года назад

Another botched GCN "experiment". You completely eliminated the advantage of light wheels... ACCELERATION!!

@Hypersonicbiker 3 года назад

What kind of test is this? This test is wrong. I'm saying as a engineer Rotating mass is so important. Two wheel's stability is rotating mass :)

@lukaskaciasvili9351 3 года назад

I love Oli’s determination to the story! Holding a wee, for results accuracy? Splendid! 🙌 ...also, seems like Alex gave up half way through. 🤔 Anyway, keep it up Oli - back to the drawing board and more tests could be done on this topic! Cheers.

@Dr.Schlitz 3 года назад

LOL. Alex just disappeared without mention.

@JBthePAdashC 3 года назад

You know who else disappeared without mention.... Tom Last!!! Where the heck did he go????!?!?!

@rikkiola 3 года назад

How do you know the added aero benefit of the deeper wheel didn't offset the data (i.e. increase the distance)? You didn't mention this benefit even though you mentioned a potential aero penalty with the wheel weights

@edt6488 Год назад

It went the same distance as the weight in the bottle with the shallower, less aero wheels. Therefore, aero didn't matter in this situation of two different depth aero wheels rolling down hill. Weight was more important here because you are increasing the potential energy into the system and that's why they went further than the shallower wheels with no weight. I suspect the coefficient of drag for the deeper section wheels was very similar to the shallower wheels in this situation, but the coefficient of drag for the shallower wheels with the weights stuck on was significantly higher. Hence, the bike didn't go as far.

@dings2063 3 года назад

Ollie, you definitely need a new GCN Waterbottle.

@matthewbaynham6286 3 года назад

No he doesn't otherwise he'll be peeing even more.

@markvincentcocjin 3 года назад

It looks like a bottle that no one is going to drink from again. Which makes sense if you're going to drop pieces of lead inside. The bottle itself looks like it fell off into the road and got ran over.

@orppranator5230 3 года назад

It only matters if you don’t want two heavy gyroscopes correcting any sort of wobbles/leaning you do.

@monkeysrightpaw 3 года назад

But how often is that gained flywheel energy wasted by braking at junctions? All the time. It's very common for road layouts to have junctions at the bottom.

@James-zu1ij 3 года назад

Once the wheel is up to speed then it effectively disappears (as in vacuum). It is no longer a factor, even up a hill. (Unless the whole bike is heavier) If your speed is accelerating and decellerating as in a complicated course, with many conners then it will affect things.

@Kimberly_Sparkles 3 года назад

Conners? Conor does seem like he could affect things with his size. I’m not sure what many of them would do or look like?

@PrzemyslawSliwinski 3 года назад

Since we are splitting an already split hair here... There is a slight asymmetry, I believe: the aero drag and gravitation add up against you on an ascent only. On a descent gravitation is your ally against a wind... BTW, shouldn't Ollie hide a bottle in a pocket at his back?

@jpj4449 3 года назад

I think the major effect of wheel weight is on "feel". The rotating wheel has a gyroscopic effect and once set in motion doesn't want to change direction. Try removing a front wheel from your bike, spin it up and then try to change the direction the wheel is pointing in. The effect is quite remarkable. I think this is why people like lightweight wheels - particularly when climbing out of the saddle, lighter wheels just feel so much better, and effort isn't wasted changing the direction of travel of the wheel - just have a look at the amount of deviation the front wheel makes when Nibali is on a steep climb - the wheels snake all over the road.

@1darthi 3 года назад

Hi Team nice Experiment. I just want to mention that in theory rotating weight should result is less kinetic energy therefore the less travel is explained. You need to consider that the potential energy you have on a hill is transferred into kinnetic energy plus the rotation energy of the wheel and this rotation energy is dependent on the weight. Just try this experiment use a hollow zylinder and a full zylinder with same weight and diameter and let it roll down a slope you will find that one is faster than the other due to the fact that the rotation energy changes by placing the weight all on the outside.

@larrylem3582 3 года назад

At the very end, Ollie points out it may matter in a hillclimb. Gee, why not do a hillclimb for a test?

@mikekelly6774 3 года назад

Great to see your dedication to this test. I don't think coasting is the right way to measure it though. It's the small accelerations and decelerations on every pedal stroke and from changes in terrain that make the difference. All you need to do is ride for a few minutes on rollers with alloy rims vs carbon and you will immediately feel the difference. The former will feel like you are riding through sand.

@rg807 3 года назад

When you put the weights on the non-aero wheels it takes longer to get up to speed. The aero wheels might take as long to to get up to speed, but they'll travel further just on the basis of the aerodynamics.

@traildoug415 3 года назад

Because nobody ever uses their brakes to slow down which would waste all that stored energy you've paid for when getting them spun up. ;)

@K777John 3 года назад

The important question is-did you check that your disks weren’t rubbing when you changed to the 808’s?? I only ask as I always have to re-set my brakes on my gravel bike when I swap wheels......

@feedbackzaloop 3 года назад

I bet, if that was an issue, the difference would be dramatic. Also you might consider shimming the rotors to equal distances, RoJ has a nice and thorough video on that topic

@wmlarch 3 года назад

Did you record and compare the time of each run? The lighter wheels should spin up faster!

@philipcooper8297 3 года назад

When you race against yourself and you still get dropped.

@rickcarson591 3 года назад

I think a chap called Galileo beat you to it by over 400 years: en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment But I applaud that you're actually coming up with simple real world tests for some of the myths of cycling. Good job, keep it up!

@rewop12 3 года назад

Starting and climbing mountains with heavier wheels (I’m talking like a pound or two more) will be much harder than with lighter wheels

@TheOkinawaBoy 3 года назад

Even it doesn't explain anything, it was pure fun to watch this video!

@timnoko3497 3 года назад

Fun fact; Added weight makes you faster on downhills. If you only do rolling runs without pedaling, starting downhill, you are correct, weight doesn't matter. Whether it's on the wheels, bike or the rider. :)

@lucilledadang1989 3 года назад

Exactly correct. The theory posited is correct, assuming a constant velocity and applied force (or lack of in this case). A lighter flywheel spins up more quickly, yet loses speed faster, this is why physics says that it makes no difference overall. However we do not exactly pedal with consistant applied torque (or lack of it) as is mirrored here. Going downhill assists distance via MOMENTUM. This multiplies the difference added weight makes. Therefore a heavier bike that takes longer to "spin down" will travel further. THE OPPOSITE is true going up a hill, given some variance in applied torque/accelation. So yes....Without the application of force, this experiment proves nothing and only shows you that the position of weight makes no difference coasting down a hill. It is not a useful experiment and you can't learn anything from it that you wouldn't logically expect. It does not apply to real world cycling per se, aside from coasting down a hill. From a physics standpoint, acceleration over inclined sections of varied gradient does make a slight difference, however the difference is very little and the aerodynamic advantage of deeper heavier wheels is in comparison very significant. Both the experiment and the use of it in order to to come to a conclusion is flawed. There are also too many variables that have not been accounted for.

@markustilichi2479 3 года назад

What about the tyre pressures between the two wheelsets?

@samtravis4822 3 года назад

Interesting experiment. What would be more applicable to the real world is testing it up a series of short, steep climbs with similar descents where you need to brake. This is usually the case with British hills and in this case I think the weight, and rotational weight especially, would hurt you more because you’re not gaining the benefit on the descent, just paying the penalty on the climb

@alistaircassidy 11 месяцев назад

Yes but it appears that that is due to the greater weight of the bike rather than where that weight is on the bike (or rider).

@zhanzo 3 года назад

It is called "moment of inertia" and it will not only require some energy to be stored in a conservative force but also effect the hysterisis curve of the wheel contact surface, i.e. the rolling resistance and tracktion. The effect is not too discernable for most modern wheels due to modern materials and design. It can easily be compamsated by changing air pressure and pattern.

@MB3Drift 3 года назад

Light wheels won’t affect the speed in a downhill like that, because they are just like a flywheel on a motor as you said. But like a flywheel, a lighter one allow to accelerate faster, but will be less stable in its RPM due to decreased moment of inertia. In a downhill the added weight increase you potential energy so you will go faster and travel further. That’s why aero bikes don’t care so much about the weight. The added weight will cause some added watts to keep the same speed, but the aero advantages will compensate and make the bike faster. In a way, like a supercharger on an engine. The added drag of the belt and rotors compressing air may cost you 40 or 50hp, but the increased admission pressure will make a 100 more hp. Overall you still have more power because the total gain is 50hp. The benefit of lighter wheels is more in the agility part. Having less moment of inertia, the bike will be more nimble and peppy, and accelerate and slow down faster. In a crit or a race it can make all of the difference in the world.

@MrJules1977 3 года назад

It affects you when accelerating, starting off or climbing hills, its basic physics, if your wheels weighed one ton you would never get up a hill and accelerate very slowly. It still affects you on the flat but less noticeable.

@TRBNTR98 3 года назад

If your frame weighed one tonne you wouldn't move it either...

@prokopf-9332 3 года назад

Wheely feel better when their lighter, more springy. But in general weight differences on wheel or any part of the bike are identical in performance.

@bikebrain 3 года назад

On a normal ride there's likely to be some braking on downhills and for junctions which will negate of the recovery of energy due to the flywheel effect and also some of the kinetic energy gained when ascending. Every time we brake energy is dissipated as heat due to friction. Also if you're using heavier bike and/or wheels you'll go slightly faster on downhills which will cause a greater aerodynamic drag. Although each instance of going faster downhill and braking will make a minimal difference, added up over a longer ride it must all count. Also, and more importantly, the lighter the bike and wheels the greater the feeling of 'nimbleness' which feels sooooo good. So it's a light frame and wheels for me (HUNT 3650 Carbon Wide Aero Wheelset).

@bikebrain 3 года назад

Oh and I forgot about the up and down movement caused by aberrations in the road surface. As you and your bike travel over every little bump the weight is lifted, again dissipating energy* reducing forward speed. More weight means more energy lost. Doesn't sound like much but added up over a longer ride it must make a difference. (*This is why softer, tubeless tyres roll noticeably faster.)

@hebrews11vs5 3 года назад

Its satisfying when science finally works in the real world. Cool experiment. I have done similar to test Crr of tubolito vs latex, but I had to keep speeds low to get aero issues out of the equation.

@nerodrive4254 3 года назад

It's mass, not weight. I prefer lighter wheels, it's just easier to climb.

@James-zu1ij 3 года назад

That's not true though. Well..according to the principles of physics. On hills, it is the total weight that matters. Rotating mass only affects accelerations.

@nerodrive4254 3 года назад

@@James-zu1ij wheels with less mass have less mass. It's that simple.

@James-zu1ij 3 года назад

@@nerodrive4254 i agree Of course a heavy bike will slow you down, butt the video is talking about wheels. Wheels only effect acceleration. Climbing general doesn't involve acceleration. Think about an impossibility light frame 0g with 6.7kg wheels. You would go up hills just as easily.

@edmundscycles1 3 года назад

@@James-zu1ij climbs do have acceleration . A bicycles power is not linier. The power from a rider arrives in surges . Ergo the gravity working on both the cyclist and wheels will slow down the bike while the pedal stroke is in the dead spot or where power input is less , then accelerates back up to speed once the pedal stroke move out of the dead spot . These accelerations and deceleration are small but have a culmative effect over time as energy is reduced in the riders reserves . Heavier wheels exasperate the issue .

@edmundscycles1 3 года назад

@@James-zu1ij and the flywheel thing is a non starter . Wheels on the ground do not act as flywheels , they have inertia . Even if they did act as flywheels a 1600g set of wheels will store a maximum of 70 joules of energy which released over a second is just about 100watts . To climb a 7% hill at 10kph I would need to produce a constant 350watts (I'm 105kg and my bike is 7.5kg, yeah I used to be a lot fitter ) . So even if I back stop pedaling the stored energy in a "flywheel" would not compensate for my loss off power at the dead spot of my pedal stroke if it was released all at once (which it isn't) . So a wheel does experience accelerations and deceleration as gravity has an effect on the bicycle and rider that exceeds any inertia held in the rotating wheel .

@martinandersson5833 3 года назад

Another interesting video. Thanks Ollie and Alex 👏👍

@move177 3 года назад

You should have change the tires from the 303s to the 808s. Because rolling resistance etc.

@mickelkobeck7376 3 года назад

Yes of course it does...people that quote the small differences...don't count the HUGE number of rotations that take place....these small differences ADD UP

@martinhighmore4185 3 года назад

This would be more interesting if you had the starting from stopped and hill climb elements, perhaps for another video?

@brianjoyce2731 Год назад

As a heavy rider (325lb system weight (147kg)), any difference in the rotating weight shouldn't make a difference. However, I have found a difference in handling between my son's bike and mine. We both have a RadMission but his is two years older. The tires are the same brand and model (Kenda Kontact) but his tread is about 3x deeper than mine. I'm not sure how much all that extra rubber weighs, but I'm sure they are heavier than my tires. I find when taking on a steep corner at high speeds, where you counter-steer and lean the bike in quite far and keep your body more upright, the gyroscopic effect by moving the rotating mass out of it's rotational plane, creates quite a different feel to the ground. Plus, the thicker rubber has a different deformation feel as it squashes as it rotates into the ground. I'm not sure which I like better. His feels more like a pedal-assisted-electric-motorbike whereas mine more like a motor-assisted-electric-bicycle.

@joneaton3366 3 года назад

Great video thanks guys. Can we please have same test please but only doing very steep a hill climb

@CameronFraserACHF 3 года назад

I understand that rotating weight doesn't matter in the course of a whole ride, but I very much like my light wheels when accelerating or going uphill, both of which I am crap at. What I don't really feel is the conserved momentum when coasting downhill. And while aerodynamics always make a difference, that difference for me is small. I'm just not fast enough that aero is as big a factor for me as it is for some.

@brianbob7514 3 года назад

Least scientific test of all time? Literally useless? Change one variable at a time please.

@robertwyland7770 3 года назад

Looks like you had fun. The reason rotating weight matters is generally ignored in all discussions of this subject. The main assumption is that things remain constant, even acceleration ( gravity in this case). The problem is when pedaling, we do not apply force to the pedals consistently throughout out one revolution. We are constantly accelerating and de-accelerating. The rotating mass, and its polar moment of inertia affect how quickly we accelerate or de-accelerate, especially as we try to change speeds. That’s why it matters, and why we all feel the difference in wheel weights.

@kvalvagnes 3 года назад

Yes this is the point ... take a TDF - it will be massive gain to have lighter wheels.

@alexanderh.9230 3 года назад

Now the most important question is: "what wheels do Olli need to not getting dropped?" ;)

@elpoutre2522 3 года назад

Probably the one with a motor in the hub

@nachiketkate5785 3 года назад

Does*

@giobaldu 3 года назад

Weight on the edge of the wheel counts exactly twice as much as non-rotating weight for acceleration. No difference in climbing performance. If you do a distance test where you roll under gravity with no pedal input, the heavier wheels actually have a small theoretical advantage: they store the same kinetic energy while rolling slower, so less energy is lost to air friction. But we are talking negligible effects compared to bike + rider weight.

@DansCampShopCoffee 3 года назад

Awesome! You guys should/could have put the weights back in the water bottle with the last wheels to see if you were able to get a little further :)

@anthonyoriordan5967 3 года назад

Rotating wheel weight isn't a major concern until the gradient rises. Right there and then a lightweight wheelset is a valuable asset to your training

@MrSmradoch 3 года назад

These slow mo are !!!SICK!!!

@royevans4581 3 года назад

I liked the look of those wheels with the weights stuck on. It says to others you are up to something sciency. 😁

@jeffr119 3 года назад

Here, let me repeat the exact comment I left on your rotating weight video from July last year. Just as true today, as it was last year. I'd like to see the math and formulas that were used for the simulation. The expert you interviewed kept speaking of bike wheels functioning as a flywheel. Twice I heard it said that "the rotating wheel stores energy and only gives it up when braking". If that is true, why do you have to pedal nearly continuously on a 0% grade to maintain speed? Bike wheels don't just magically keep rotating, there is bearing friction, along with the friction between the tires and the ground. That paired with the varying resistance provided by the air/wind adds up to multiple factors of resistance that have to be overcome when riding. That is why reducing the rotational mass is important, the rider is exerting energy to keep that wheel rotating. Oh, and if the weight of the wheels really was not that relevant, why don't F1 and pretty much all other motorsports racing teams use good strong steel wheels on their race machines? Nope, they use lightweight forged aluminum, some use high dollar carbon fiber wheels. They also use light weight braking components like carbon-ceramic brake rotors instead of cast iron. They do that to reduce rotating mass. Sure bikes move much slower and with much slower wheel rotating speeds, but if it's good for race cars, there must be benefit for cyclists, even if the benefit is minimal. I will continue using my shallow section lightweight carbon fiber wheels over any deep section CF or even aluminum wheels.

@aaronpostlethwaite8449 3 года назад

To increase rotating weight just use 600g of sealant in your tyres. That way you eliminate the aero variable and have a proper scientific result.

@rasmuswi 3 года назад

Or empty the water bottles into the tires.

@EverythingsFine82 2 месяца назад

A few years ago, I thought a wheel upgrade would be great. I couldn't feel any performance difference between a nice (1550g) wheelset and the original (1900g) wheelset when riding. The nice wheelset had GP4000 tires compared to Open Sports and still if blindfolded, I couldn't tell a difference when riding. The only functional advantage was lifting the bike onto a bike rack was easier with the light wheels.

@luukrutten1295 3 года назад

Repeat the experiment with a box section wheel 32 spoke. There you can easily stick the weights to the rims in between the spokes. Will not negate the aero as much as on an aero wheel. However I would recommend to have the weighted rims balanced. Since an unbalanced mass on rotating wheels can add all sorts of vibrations and strange feelings. However whenever you are braking a lot like on a switchback descent or in a tight crit. The inertia is lost on braking.... And who doesnt like the feeling of light wheels.

@menelaos951 3 года назад

When someone is perfect at pacing, with a minimal variability, the rotating mass indeed does not matter. In the real world of traffic lights, amateur unskilled cyclists where one's speed changes constantly, rotating mass matters infinitely. As always, very amusing to watch...but this particular video goes no further as it's scientific value is nil. :)

@HotelPapa100 3 года назад

The one situation where rotational inertia counts is the sprint. That's where the kinetic energy is lost at the end when crossing the line, and quick reaction is paramount. If you were the type of rider who can profit from inertia stored in the system prior to launch of the sprint, you wouldn't be a sprinter; you'd try to win the race before.

@RicardoRibeiro1978 3 года назад

3:25 - worst energy drink ever 😂 Would have been fun if this video was posted on April 1st. I can only imagine the comment box

@eparker3157 3 года назад

All the critiques notwithstanding, I think we should applaud Ollie for even attempting to bring an analytical approach to cycling issues. His various sciene-based videos on GCN, whether on wind tunnel tests, nutrition, etc. are the best there is. I look forward to more of the same.

@chrissmith2729 3 года назад

In the road world, where there is hardly any significant external variable such punchy incline and braking, the argument of why spend the money on fancy light wheels is more valid. But it is very significant in the MTB world, which I have experienced first hand the differences. Lighter wheels and tires netted me a 4 tooth difference in chainring size between bikes, 34 on my xc bike and 30 on the trail bike with more robust wheels and tires.

@tychoMX 3 года назад

Easier way to do this - add the weights on the spokes at different distances from the hub? You still get an aero disturbance but it's easier to control variables that way.

@AmaroqStarwind 2 года назад

Speed isn't what's affected most; it's handling. Not just acceleration and deceleration, but also cornering and stability. Lighter wheels respond a lot faster.

@minkedweasel51 3 года назад

you should try the mavic comete +/- disc wheel it had 12 weights in the disc.

@testbna4965 3 года назад

Nice video, and cool editing, but wind makes the most difference here. It has to be done indoors to be effective and able to be repeated or "peer reviewed". Without knowing the wind conditions even the breeze from a passing car would make a difference which would account in the long run. Also, tires and pressure has to be exact. And you just can´t "let go" by yourself, because there are diffenrences in the way you left that wall. It has to be someone just letting you go by gravity. Again, cool video, but lots to be desired...

@jed7939 3 года назад

Video actually starts at 10:51

@333wheeler 3 года назад

I remember when using old school Campag pedals .. Toe Clips etc. The Black ones compared to the Steel heavier ones . There was a noted difference . You could feel it every time you swapped. Maybe 24 and 28s lace ups were more aero than bog 36 s as well another gain most went for.

@JimGrahamNH 3 года назад

Interesting video, but I wonder if it could be missing a key point. My non-physicist self thinks that when you're pedaling, you aren't actually applying constant power evenly with each pedal stroke. Instead there must be slight variations in power with each revolution of the crank, meaning you slow down and speed up by incremental amount each stroke. So, even though it may feel like we're applying consistently smooth power, we're actually accelerating a wee bit each stroke to keep our speed constant. As this video suggests, accelerating is harder when a wheel weighs more. Ergo: Lighter wheels are faster -- when you're pedaling. But lighter and heavier wheels are about the same when just coasting.

@michaelwestbrook8255 3 года назад

Interesting test, but... This point may have been mentioned but wouldn’t a better test have been against a set of stock/cheap wheels that bikes often come fitted with, rather than an expensive set of aero wheels? That would help answer the question about where money is best spent on upgrading a stock bike/cyclist - wheels, groupset, fasting clinic etc?

@benhowe2087 3 года назад

Wheel weight affects acceleration and deceleration of the wheels. As you pedal the ground undulates. There is subtle ups and downs. Added wheel mass will add force needed to overcome these accelerations and decelerations. Your test completely eliminates this effect. Wheel weight affects your power transfer to the ground. Added weight on the wheels decrease how much power you transfer to the ground through peddling. Try your experiment on a lumpy road holding a steady watts for a set period of time over distance. Even better use an e bike with a set watt output. Heavy wheels will travel a shorter distance. Add a few stop signs to make the difference more apparent.

@DaveCM 3 года назад

I really wish you could swap out your camera bike for an electric powered one.

@matthewbaynham6286 3 года назад

Petrol motor bikes don't have a catalytic converter so they will release NO2 (Nitrogen Dioxide), and your body is able to absorb NO2 much easier than O2, it's like 20 times easier. So if you are cycling behind something that emits loads of NO2 then you might get dropped. It might be better to have a petrol camera car which will by law have a catalytic converter, then it won't emit NO2. Although it'll emit massive amounts of CO2 which will go towards global warming and destroying the planet and contributing to the death of all life on this planet. But it won't have any effect on you being dropped, because your body will still be able to absorb the same amount of O2. But using electric bikes and cars would be better still. And they definitely have the range for even the longest pro race.

@andrewjones2042 9 месяцев назад

The experiment to be run is: peddle about half way down the downhill and input and fixed amount of energy E=(Power)d(time) and see it the energy you but into the bike is better stored in the deep (80mm rim) or the shallow (30mm rim) rim. To keep the weight of the bike constant, add weight to the bottle when you put on the shallow rim.

@stephenrowlands843 3 года назад

The acceleration at the begining is the same for all, regardless of weight, as the accel is a component of gravity and the angle with the horizontal, i.e. a = g sin (theta) , where theta is the angle from the horizontal.

@larisonjohnson 3 года назад

8:42 - When a scientist is amazed that science actually works! What were you expecting...Ollie discovers free energy? ROTFL! Keep up the great content!