How much does rotating wheel weight matter?

[SpokeyDokey]

An alternative view I wasn'taware of. Article is 3 years old. Has this been disproved or not?


View: https://youtu.be/0QDnUkUaQfk?si=UGGC7B2vpKoy5nMR

 

[cyberknight]

heavy wheels ... 1600 grams

 

[Aristotle Kristatos]

heavy wheels ... 1600 grams

That is weighty

 

[wafter]

Can't be arsed to watch the vid but I've done the calcs in the past. From an acceleration perspective rotating mass is disproportionately influential, as you have to accelerate it both linearly and angularly.. so a given mass saved from the rims will have a greater effect on acceleration than the same mass removed from the frame, for example.

As the chap at the beginning of the vid states, input energy isn't lost, it's stored - lighter wheels will accelerate faster for a given energy input, but also decelerate faster. This matters on a course with lots of speed changes (so something tight and twisty) and of course if you're actually concerned with speed. On something like a tourer where you're coasting a lot and anticipating stops in advance it's less of an issue.

Wheel mass also affects gyroscopic stability, with less rotating mass potentially making the bike feel more responsive but also less stable..

 

[cyberknight]

That is weighty

depends on your budget

 

[ebikeerwidnes]

One the the comments says that his wife tells him to loose 5Kg from his belly before he spend 2000 Euro on saving weight on his bike

which sounds about right

having very little knowledge of the subject - even I noticed that the data is biased towards situation where the speed is constant - and hence aero is more important.
To be fair the bloke does say that his company is aero based so he isn't hiding anything.,
However, I did think that in a race where you might have more sharp corners and be accelerating and braking more often due to other traffic - then the number he used would not be as relevant.

It does make me think that choice of wheels for a pro on a long stage is more complicated than I had thought about.
If they are intending on getting into the break on a long rolling course then aero would be the best bet even with more weight - keep momentum up over the rolling bits and more gain from aero than loss from the weight
but is they wanted to be part of the spring lead out and shepard the sprinter into the final - then the ability to accelerate faster to get up to the fron - and accelerate out of corners approaching the end might well be more important

I present all this based on my vast experience of watching the telly when bikes are on it!
so it is basically just what I was thinking with naff all expertise

 

[Jameshow]

I would think aero would be a majority concern except in the Alps etc where weight might be a factor. But tbh all pro bikes will be around 6.7kg limit so weight really isn't a factor.

 

[Cycleops]

I've no idea, I just ride my bike and always get where I'm going.

 

[cyberknight]

One the the comments says that his wife tells him to loose 5Kg from his belly before he spend 2000 Euro on saving weight on his bike

which sounds about right

having very little knowledge of the subject - even I noticed that the data is biased towards situation where the speed is constant - and hence aero is more important.
To be fair the bloke does say that his company is aero based so he isn't hiding anything.,
However, I did think that in a race where you might have more sharp corners and be accelerating and braking more often due to other traffic - then the number he used would not be as relevant.

It does make me think that choice of wheels for a pro on a long stage is more complicated than I had thought about.
If they are intending on getting into the break on a long rolling course then aero would be the best bet even with more weight - keep momentum up over the rolling bits and more gain from aero than loss from the weight
but is they wanted to be part of the spring lead out and shepard the sprinter into the final - then the ability to accelerate faster to get up to the fron - and accelerate out of corners approaching the end might well be more important

I present all this based on my vast experience of watching the telly when bikes are on it!
so it is basically just what I was thinking with naff all expertise

i have been using a bike thats maybe 2 kg lighter than my usual commuter bike the last 2 weeks , tbh by the time i add panniers, mudguards, lights etc you can guess how much difference its made erm not enough to even register .

 

[presta]

From an acceleration perspective rotating mass is disproportionately influential, as you have to accelerate it both linearly and angularly.

It is, but the difference it makes is only small. I have 35mm Marathons and Mavic A719s, which are not light components, but even then the wheel moment of inertia only adds 2.33% to the total inertia of bike+rider+luggage. Racing cyclists are looking for the 'marginal gains', but for the rest of us it's not much to worry about.

 

[ebikeerwidnes]

A handful of change in you pocket could make more difference than several hundred quid - in other words!

Which is why all proper cycle cafes need to accept cards - I suppose!

 

[wafter]

It is, but the difference it makes is only small. I have 35mm Marathons and Mavic A719s, which are not light components, but even then the wheel moment of inertia only adds 2.33% to the total inertia of bike+rider+luggage. Racing cyclists are looking for the 'marginal gains', but for the rest of us it's not much to worry about.

Indeed; I did an exercise on here a while ago equating cost of upgraded wheelsets versus the associated acceleration / ascention gains and it was utterly ridiculous... but the industry needs us to believe that these marginal gains are significant to the average rider and hence of some tangible value. £2k spunked on go-faster-hoops to get up that hill 1% faster than you did it last week is good value... right?

I did start a reply involving my Brompton as that obviously has little wheels, associated reduced rotating inertia and corresponding behaviour... while certainly great for blitzing unsuspecting racing snakes off the line, I'm not sure I'd want to throw thousands at a road bike to make it handle that way... if that's even possible given the constraints involved.

 

[Jameshow]

Indeed; I did an exercise on here a while ago equating cost of upgraded wheelsets versus the associated acceleration / ascention gains and it was utterly ridiculous... but the industry needs us to believe that these marginal gains are significant to the average rider and hence of some tangible value. £2k spunked on go-faster-hoops to get up that hill 1% faster than you did it last week is good value... right?

I did start a reply involving my Brompton as that obviously has little wheels, associated reduced rotating inertia and corresponding behaviour... while certainly great for blitzing unsuspecting racing snakes off the line, I'm not sure I'd want to throw thousands at a road bike to make it handle that way... if that's even possible given the constraints involved.

I don't know but I can tell the difference between 32h traditional training wheels vs rs10 and vs DA c24 /c35 / c50

You have to be particularly daft to argue no difference between them.

But you wouldn't want to commute or tour on DA c24.

Nor would a century in 6hrs on 32h / marathons on a warm summer's day make for pleasant ride.

 

[Cycleops]

.. but the industry needs us to believe that these marginal gains are significant to the average rider and hence of some tangible value. £2k spunked on go-faster-hoops to get up that hill 1% faster than you did it last week is good value... right?

Kings new clothes comes to mind. You're right, keeps lots of cycle component companies in business.

 

[SpokeyDokey]

Not too long ago there was a lad on the Trek sub-reddit who claimed to have changed his standard wheels for some lighter ones (can't remember what) and gained almost 3mph on his average speed. Amazing!