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Crank Arm Size?(8 posts)

Crank Arm Size?dpoch
Jun 24, 2002 12:23 PM
What are the benifits/drawbacks to a longer crank arm? I am currently riding a 175 and thinking about switching to a 180 crankset.
re: Crank Arm Size?Juanmoretime
Jun 25, 2002 1:30 AM
The benefit of a longer crank arm is obviously more leverage, it's a longer lever. The negative is you will lose RPM on your cadance plus put more stress on your knees. How tall are you and do you really need a longer crank? I rode 175's for many years and went to 172.5's last year and found I climb better spinning more.
re: Crank Arm Size?gs6769
Jun 25, 2002 4:03 AM
I'll second juanmoretime. I've got 175s on my Bianchi, and 172.5 on my Klein. After getting used to them I found I had improved leg speed and spinning ability with 172.5. I do like the 175 for longer distances but the 172.5 seem better for day to day hammering.
Also, you may have a hard time finding 180 mm. I think 175 is the longest production length for both Campy and Shimano.
What about going the other way: 170mm???kapalua
Jun 25, 2002 8:02 AM
I ride a 172.5mm crank-arm now. Are there any significant differences switching to a 170mm? I'd like to pick up my cadence a little as well.

What about going the other way: 170mm???Juanmoretime
Jun 25, 2002 10:08 AM
What is your height and inseam length? I'm 6'1" with a 34" inseam.
Jun 25, 2002 10:32 AM
I'm 5'9", and inseam is approx. 32 in.
Jun 25, 2002 4:00 PM
172.5 seems right. You could always try 170's, you would need at least a week on them to get acclimated. Check around with some of your friends who cycle, if you could borrow a set that someone has laying around to ride and see if the make a difference. LoL.
Jun 25, 2002 4:39 PM
You will find no high quality data to support any particular crank length as being better than any other. This is true whether or not you correct for leg length, femur length, etc. What little research has been done on crank length suggests that people adapt to different crank lengths and there is no optimum or formula related to body proportion. On the other hand, you will find lots of anecdotal or low quality data to support all kinds of conclusions, and more theories than you can shake a stick at. A rider's response to changes in crank length is 1) highly individual, 2) dependent on riding style and the event (TT, climbing, crits, track racing, etc.), and 3) most important, highly adaptive. This is why it is so hard to study the effect of crank length.