Bicycle Mechanics - Crank length: MTB vs Road (or, Guess the magic number!)

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jonnyweale
07-26-03, 04:55 PM
Hi all.

This question comes up a load (I've just checked the forum) but I couldn't find what I'm looking for:

I have always ridden MTBs but am considering building myself a road bike:

1) Should I have the same crank length on a road bike as on my MTB?

2) On my MTB I ride 175mm; being 6'1" (with a 33" inside leg and proportionately long thighs) is that about the right length? Is there a formula to calculate the most efficient length?

Cheers,

Team

late
07-26-03, 05:29 PM
There are formulas for everyithng. But the bottom line is what works for you.
With a 33" inseam, 175 sounds reasonable. The thing with road cranks is you want a higher rpm than on a MTB. But with those long legs of yours, the traditional 170mm crank would be too short....I think
Phatman
07-26-03, 06:42 PM
you have the exact same proportions as me. I ride a 175 on the fast road bike, and 170s on my touring bike, mainly because the roadie came with 175s. They feel very different, and require a different seat height, but after getting used to them, I like the 175s better, even though I can spin faster on the 170s. if you are used to 175, stick with that.