Mountain Bike Reviews Forum banner
1 - 7 of 7 Posts

·
Dream it, Do it.
Joined
·
1,782 Posts
Discussion Starter · #1 ·
I'm getting ready to build up a small 26" bike for my 12 y.o. and am thinking about the right crank length. My initial thought is to just go with a 165 and not to worry about it. Any thoughts?

I found this great chart on Dans Comp for BMX crank sizing which may or may not be relevant for mountain biking: Crankchart at Dan's Comp

Denim Text Jeans Line Pocket
 

·
Registered
Joined
·
549 Posts
when I went to 125mm on road bike and 135mm on the MTB and cross bike....much better....couldn't stand my 165mm....glad I went short....wish I had thirty years ago...that chart is crazy wrong....29" inseam...
 

·
Registered
Joined
·
2,191 Posts
My initial thought is to just go with a 165 and not to worry about it. Any thoughts?
FWIW, I took the "don't over think it" strategy when I put 165s on my daughter's bike when she was 11. Seems to have been a good choice for her.

https://forums.mtbr.com/families-riding-kids/2005-cdale-f800-re-build-my-11-yr-old-851395.html



The only problem is that the turkey is growing out of the Size S already. I found a Size M for next year that I plan on putting 170mm cranks on.



Luckily, my youngest can move up to the Small next year. Then I'll sell (or part out) the 24" wheeled bike with 152mm cranks

https://forums.mtbr.com/vintage-retro-classic/1995-cannondale-mc400-youth-sized-killer-v-24-wheels-534377.html

 

·
Registered
Joined
·
283 Posts
you need take into account body position and possible gearing... plus rider skill level. A new rider is going to prefer their saddle as low possible. Body position is not going to be correct anyways and you are not going to get the benefits of the short arms. The short arms will allow you to raise your seat higher (allowing proper knee extension) and most young rider feel more comfortable when they can touch both feet on the ground. If that applies to your little one that like to be able to touch both feet on the ground, longer cranks will provide a more comfortable ride (except for hill climbs, will require them to be out of the saddle). If more advance rider, especially if doing long or a lot of hill climbs, I would be looking at shorter cranks to be able to raise their seat to put them in proper riding position.
 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top