Crank length for cycling

Hi Fastcat team,

I’m curious, i recently had a professional bike fit and i was advised to go from 172.5mm cranks to 165 or 167.5mm.
My inseam is 810cm so i have short legs, the fit was done by Retul.

Is there anything much to be gained in 7.5mm? Or is it marginal effect.

Thanks Scott Evans FTFP👍.

Hi @evansscott199 - thanks for your question - this is a good one.

What are/were your goals from the fit? Are you trying ‘to get more aero’ are you a multisport? I am just asking to get the background bc the idea behind going to a shorter crank is to help your hip angle when you are in your aero bars and/or run off the bike.

If you are not TT’ing, hmmm, I am not sure the background of the fit. Honestly - I’d ask your bike fit professional the why behind the change.

Thanks for the fast reply👍
Mainly road racing and crits, i have a long torso and arms, short legs so I’m long and low. It was explained to me that at the top of the stroke there would be a dead spot as my legs roll over the cranks and to improve hip angle.

I’ve never had any injuries or anything with 172.5, ive got an FSA powerbox $1500, so if it’s going to make a lot of difference I’ll swap but don’t want to waste money on a little gain.

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I can share my experience although I have very little expertise. I also do road races and crits, not much else. I have 32" inseam which is about 81 cm. I had a fitter recommend me switch from 170 to 165 cranks and two different fitters afterwards said leave it at 165. It does help in being able to keep my cadence higher as well as removing dead spots like your’s suggested.

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Thanks coach Jake,

You have the same inseam measurement as me, it’s a good excuse to buy some new cranks.
Just curious what power meter you use? I’m currently using fsa powerbox which is a Power2max unit.
I’ve heard good things about Farvero assioma power pedals.

I’m not coach @Jake :wink:

I have a Quarq DZero but have had the Favero in the past. The Favero worked well but I wanted dual sided and lost less money switching than if I were to buy the second pedal.

Many of us started riding MTBs, many of which come with 175mm cranks. So I started riding road bikes with 175mm also. I made the switch to 172.5 a few years ago and noticed an immediate improvement in power & cadence. A few months ago, I decided to try 170mm because of the anecdotal evidence I’ve heard from TT “experts”. I have (2) road bike set up, one bike has 172.5 and the other 170mm. After reviewing power curve data from many back to back rides, I recently made the decision to convert to 170mm cranks exclusively. Favero Assioma Duo pedals here also…love their accuracy, consistency and most of all, rechargeability!

Awesome Dan,
Definitely going to 165mm the only issue i have now is deciding which power meter, I’ve had Stages gen 1 and 2, currently on FSA powerbox which is Power2max, it’s been flawless. But Farvero assioma are the one’s I’ve decided on, cranks will either be Dura ace or Rotor Aldhu.

Thanks for the feedback :+1: