Crank length

[Brucey]

one of my chums used 170mm cranks for years, tried 175mm and found it made his knees hurt, then changed to 172.5mm and has been happy ever since.

To my annoyance many years ago I found I'd become habituated to 6-5/8" cranks, which you can't buy these days. 170mm is just a few mm longer but enough to be felt.

cheers

[alexnharvey]

Yes you’re correct. A lot of pro’s typically use 169 or even shorter on their race bikes ( Froome uses 168-169 mm during the TDF IIRC ).

Shurely shome mistake?
1 or 2 mills is a very marginal gain.
Must be specially made too.

Aero gains is the reason why Froome and other pros now use shorter cranks, this makes more of a difference than the crank length itself. Opens up the hips which lowers or allows the torso to be lowered more and thus also aids breathing when compared to a longer crank for same position.
It also apparently has an effect of lowering blood pressure.
Shorter cranks also help to eliminate dead spots in the pedalling action.

https://www.cyclingweekly.com/news/prod ... ter-188288
BUT for the 2017 Vuelta Froome rode 175mm cranks on his Pina dogma F10 Xlight according to GCN when they had his bike, this is in line with the thinking of more climbing or sprinting could benefit longer cranks. https://www.globalcyclingnetwork.com/vi ... spa-a-2017

Does anyone know if any professional rider uses different length cranks on each side?

[Marcus Aurelius]

Shurely shome mistake?
1 or 2 mills is a very marginal gain.
Must be specially made too.

Aero gains is the reason why Froome and other pros now use shorter cranks, this makes more of a difference than the crank length itself. Opens up the hips which lowers or allows the torso to be lowered more and thus also aids breathing when compared to a longer crank for same position.
It also apparently has an effect of lowering blood pressure.
Shorter cranks also help to eliminate dead spots in the pedalling action.

https://www.cyclingweekly.com/news/prod ... ter-188288
BUT for the 2017 Vuelta Froome rode 175mm cranks on his Pina dogma F10 Xlight according to GCN when they had his bike, this is in line with the thinking of more climbing or sprinting could benefit longer cranks. https://www.globalcyclingnetwork.com/vi ... spa-a-2017

Does anyone know if any professional rider uses different length cranks on each side?

Not that I’m aware of at present. However Froome may have to, because of his injuries.

[KM2]

Alex Harvey wrote

Does anyone know if any professional rider uses different length cranks on each side?

I would guess, different thigh length, the more horizontal component.

[Debs]

I'm not an expert, but would think if a pro-cycle racer had legs of a slightly differing length [like many people have] the adjustment would be met by different shoe sole thickness, or cleats.

[Morzedec]

My inside leg is slightly shorter on one side than 'tother, the result of an old rugby injury.

Go on, now explain to me which cranks (apart from our current crop of politicians) I ought to be looking at.

Apparently Hopalong Cassidy had the same problem with his stirrups.

Happy (if lopsided) days,

[Mike Sales]

Interesting article on crank length.

https://cyclingtips.com/2017/09/crank-length-forget-leverage-power-fit/

I will discuss this in more detail below, but for those hoping for a quick answer, here it is: there is no evidence that crank length has an effect on a road cyclist’s power or speed.

There is too much to summarize, but it is a comprehensive review of the literature.

[Debs]

GCN talk about crank-length [ An interesting 6 minutes ]

https://youtu.be/vUygkHlcVMQ

[Brucey]

My inside leg is slightly shorter on one side than 'tother, the result of an old rugby injury.

Go on, now explain to me which cranks (apart from our current crop of politicians) I ought to be looking at.

Apparently Hopalong Cassidy had the same problem with his stirrups.

Happy (if lopsided) days,

the simplest thing to do is to use packing under the cleat/on the pedal one side. However if the shorter leg is shorter mainly in the thighbone, there is something to be said for a shorter crank on that side perhaps as well as some packing. Because your body will have to some extent accommodated to the difference in leg length a 'full correction' (eg packing that is as thick as the difference in measured leg length) is not usually required.

cheers

[The utility cyclist]

one of my chums used 170mm cranks for years, tried 175mm and found it made his knees hurt, then changed to 172.5mm and has been happy ever since.

To my annoyance many years ago I found I'd become habituated to 6-5/8" cranks, which you can't buy these days. 170mm is just a few mm longer but enough to be felt.

cheers

You can notice the difference in 1.725mm, how?

[Brucey]

dunno, but I did. The circles are about 3.5mm different in size. Most people do notice a 2.5mm difference in crank length; few try a smaller increment than that and I only did so accidentally.

Few people have exactly identical leg lengths. I have measured hundreds of people and when my legs were measured they were found to differ by a relatively small amount; put it this way most people have legs that are less symmetric than mine were. That was a long time ago though; maybe things have changed since then; after all bits do wear out, drop off, go peculiar etc as time goes on.

cheers

[The utility cyclist]

I deleted what I said re leg length etc because the Mods are a bit touchy lately.

[Morzedec]

Brucey, thanks for that. Too old now to try new cranks: I'll probably be dead before my legs adjust to them.

I've also got odd feet: well, odd sizes, that is, cos' ones a 12 and the other a 13. Cycling shoes? - forget them, if anything at all fits then buy it!

Happy days,

[Cyril Haearn]

Probably one leg is stronger than the other, the right usually
For marginal gain one might try a longer crank on the right
Or maybe not, the legs might get used to moving diffently, might be hard to walk after

[foxyrider]

one of my chums used 170mm cranks for years, tried 175mm and found it made his knees hurt, then changed to 172.5mm and has been happy ever since.

To my annoyance many years ago I found I'd become habituated to 6-5/8" cranks, which you can't buy these days. 170mm is just a few mm longer but enough to be felt.

cheers

You can notice the difference in 1.725mm, how?

How? who knows the mechanism but i can feel different cranks, tyres and bar widths. Certainly if you regularly use one size, and variance from that can be felt by pretty much anyone, i'm guessing a lot of people put it down to just being different rather than identifying what is different.

i have bikes with 170, 172.5 and 175mm cranks and when swapping machines, i can tell the difference but soon become accustomed. i have quite long levers and find i'm most comfortable with the 172.5 size which is my default, the 170 are an historic aberration and the 175's give me some extra leverage on the poor climbing small wheeler.