Mountain Biking - crank length, SS 29er

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idcruiserman
05-02-08, 02:01 PM
I'm building a single speed 29er, and I need to choose 175 or 180mm cranks. I've read some of the discussion and understand that the longer crank may help with leverage. I have 175s on all my bikes but one, and I am leaning towards 180 for the halibut. If it matters, I'm 6'.

I compared the pedal to ground clearance with my 26" 175mm crank K2 and this 29er, and I'll gain ~0.7" of clearance even with the longer cranks.

Anyone running 180mm cranks and regret it?

thx, Eric

ProFail
05-02-08, 02:38 PM
Take your index finger and thumb and hold them aprt so they are about the length of a medium sized ant.



This is the difference in length between a 175 and 180mm crank arm.
idcruiserman
05-02-08, 03:15 PM
Yeah, I've got a ruler :). 5mm is actually a pretty large difference. I certainly notice if my seatpost is 5mm too short or tall :).

Thor29
05-02-08, 03:59 PM
Because ther aren't that many choices for 180mm length cranks, I run standard 175mm cranks on all of my bikes (including my single speed 29er) except my fixed gear road bike, which runs 170mm cranks for a little extra ground clearance in corners. Running longer cranks might work better, but I doubt there's that much of a difference. But anyway, I'd suggest asking this question in the MTBR 29er forum - there are likely lots of people there who have used longer cranks and have something to say about it.
idcruiserman
05-02-08, 04:28 PM
I didn't realize there was such a forum. I'll try there. thanks

up the irons
bhc
05-03-08, 04:24 PM
Everyone's experience can differ, but I found 180 was noticeable. I ride a Haro Mary SS. I really don't notice the difference spinning on the flats, but climbing is where I found it to be a plus. But then that also could be attributed to the 29" tire, as I have not ridden a 29er with a 175 crank.
deraltekluge
05-03-08, 04:51 PM
Yeah, I've got a ruler :). 5mm is actually a pretty large difference. I certainly notice if my seatpost is 5mm too short or tall :).Really? That's only two tenths of an inch. I don't think I'd notice.
idcruiserman
05-03-08, 04:55 PM
I definitely notice it on my road bikes. Maybe not so much on my MTB due to being out of the saddle more, etc.

I ordered the 180mm cranks.