Crank length question

[fmradio516]

I usually do 175, but did 180mm on a bike that had a slightly too short seat tube for me. Instead of raising the seat more and causing hard neck pain for me, I lengthened the crank instead. Doesnt make much of a difference otherwise.

[mattsurf]

Originally Posted by vincenz

Some people can tell the difference and some can’t. I could tell going from 172.5 to 170, but only slightly. I don’t have long legs. May be different for you. Only way to know would be to try.

I can't tell going from 165 to 170, however, I notice a 172.5 straight away.

[Mark McM]

Originally Posted by vincenz

Some people can tell the difference and some can’t. I could tell going from 172.5 to 170, but only slightly. I don’t have long legs. May be different for you. Only way to know would be to try.

In some cases, I think sensitivity to crank length can depend on rider position. I ride my MTB in a more upright position, and I find that I don't notice much difference between crank lengths However, on my road bike, I sometimes hunker down into a low position, torso nearly horizontal, knees rising up close to my chest. A few extra millimeters in crank length means my knees have to come up higher, limiting how low I can bend my torso. Here, I strongly prefer shorter cranks. I think this is part of the reason that triathletes (who ride in low, aero TT positions) are now favoring shorter cranks.

[Jef58]

Originally Posted by pasadena

Track sprinters like Hoy ran 165's
2500w sprints at 75kph.
Yes, track needs to prevent pedal strike, but if longer cranks were faster, they would certainly use them.

Try shorter cranks, they may help you get more aero and improve your fit.
If you don't have those concerns, you might not notice much difference

Going between my track bike (165) and road (used to use 172.5) I felt a huge difference.
I now use 170s and love them, though am thinking of going 165 and getting more aero.

I split time between a single speed/fixed with 165 and road with 170. I recently switched to 165's for both and it feels better and more natural for me. I ride a small bike for comparison sake.

[Sjambok]

I recently had a retul bike fit done. The fitter started me with 170s since that’s what I’ve ridden for the last year or so (from 172.5s). Once we dialed my road style setup, the fitter adjusted down to 165s. I immediately could tell the difference. He said I probably prefer shorter cranks due to my tight hips/hip flexors.

[CNY rider]

Also a short guy here,and I generally ride 170 mm.
I don’t notice anything different on 172.5.
If I spend time on 175s my knees get achy.
What does all of that mean for anyone else? I’m not sure.