Crank arm length question
 

I'm 5'10'' with a 32 inch inseam. I've been riding 172.5 cranks for the last 15 years. I'm about to set up an old made in France Eddy Merckx frame that I found at the dump into a fixed gear. I have a DuraAce crankset from about 1992 that I plan to use but it is also a 172.5 crank length. Is it bad to ride a fixed gear with the longer cranks? I will also still be riding my road bike and that is equiiped with 172.5's. Would it be a bad thing to be riding 2 different crank length's. What do ya think?

Thanks,
Bob

well, the first question is not a new one - I run 165s for streettrack. makes cornering easier. More info here/stories here:
http://bikeforums.net/showthread.php...t=crank+length
http://bikeforums.net/showthread.php...t=crank+length

As far as 2 diff lengths on 2 diff bikes, I ran 180mm on my SS MTB and then had 165mm on the track. Yeah, I felt it. So I chose track. But not sure of the difference you feel and how that will effect the different rides.

the typical issue with crank length on road-to-fix conversions is pedal strike during cornering. a shorter crank (like 165mm) buys you quite a bit of extra lean without worrying about hitting bottom. and hitting bottom is uncool.

as for riding two different lengths, i'm pretty unsophisticated but i've noticed no difference in general pedaling between the 165s on my track bike, the 170s on my road bike (which i haven't ridden much lately) and the 170s on my other fix. i will be swapping the 170s for 165s on the other fix soon, for peace of mind.

well, even i would probably notice 15mm of difference!

I am thinking of getting a set of 160's. down from 175. From what I hear the shorter length with the lower gear like my 42x15 helps with spinning out, or at least helps with high cadence and of course pedal strike... Eddy Merckx frame in a dump, you lucky dog!

Oh yea and I don't think you will notice a difference in crank length between bikes since it is an integral part of the drive train. Changing length on the same bike may be noticeable since you have the same gear ratio.