Crank arm length

[tedsti]

I am looking to pick up a used road bike and have noticed that 172.5 mm crank arms are on a few of them. Does anyone use shorter arms for road riding? Is it weird switching back and forth?

Ted

[Ish]

Ted,
I use 175mm on all my bikes (road and mtn).
There are some theories on shorter vs longer based on height and if you mash gears vs. spin.

[grizzly adam]

Not sure how accurate any of this (http://www.roble.net/marquis/crank.length) still is....


The general rule of thumb is: * below 5'10 use 170mm cranks on for general (road) racing and training, * 5'10 to 6'1 use 172.5mm cranks, * 6'1 plus use 175mm cranks,And modify for specialized events: * subtract 2.5mm for track racing (or more on short steep tracks or short events), * subtract 2.5 to 5mm if you have frequent knee problems, * add 2.5mm for time trials and hilly races, (and MTB races), * add 5mm for pure hillclimbs.Roger Marquis(www.roble.net/marquis) (http://www.roble.net/marquis/)

[funky-funky-chicken]

I've traditionally always had 172.5 on my road bikes. For a couple of years I had 175mm on my touring bicycle. After returning from tours (appx. 800-1000 miles) every summer, I would have joint pain in my hips. Since switching over to 172.5's I've never felt better.

I've tried my hardest to get used to using 175 for off road riding... Last year, for the 24HoursOfAfton, I used 172.5's off-road too and it just felt so much better.... So, now EVERYTHING gets the same for me. It depends on the person though, some people can switch back and forth and/or might be more comfortable with one or another. I'm just a bit more sensitive I guess... I pay close attention to bottom bracket length and "Q-Factor" too.

[SickBoy]

I'm trying 172.5's on my new singlespeed this summer. I typically run a little bit undergeared compared to a lot of other people (like James) so maybe shorter cranks are a better fit for undergearing on a ss. We'll see, I guess.