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Left crank = 172.5, right crank = 175(9 posts)

Left crank = 172.5, right crank = 175BowWow
Oct 30, 2002 12:38 AM
This is sort of hypothetical, but my left leg is about 3/4" shorter than my right. What would happen if I ran two different crank lengths? Would I get a smoother/more effective stroke? I feel that my right leg "carries" my left leg, especially in the left downstroke (right pulling up). Any thoughts? Or am I just barking?

re: Left crank = 172.5, right crank = 175TUT2222
Oct 30, 2002 4:10 AM
I have a 170 left, and 175 right, and it has helped me. But I was only compensating for about 3/8 of an inch. With the difference you have, what about different cranks and cleat shims?
Std advice = shim half the distanceKerry
Oct 30, 2002 4:36 PM
So for a 3/4" difference, you would shim 3/8". Since this is a pretty large delta, 3/8" may not be enough, but 3/4" is probably too much. You'll probably be experimenting to find what really works for you.
3/4" equals 19.05 mmbigrider
Oct 30, 2002 4:39 AM
You are only talking 2.5mm of distance on the cranks. I am not an expert by any stretch of the imagination on this subject but I would also try to build up the cleat by a 3/4" shim between the cleat and the shoe.

Do you wear special shoes when not on the bike?
Nothing will help you... your a freakPODIUMBOUNDdotCA
Oct 30, 2002 7:01 AM
Just kidding! But you could try shimming your shorter legs cleat. Its a cheap and relatively effective solution. Using different crank arms is expensive so unless your competing at a high level I'd advise against it. I have an about 1 cm (3/8") difference in leg length and I have yet to compensate at all for it.

Oct 30, 2002 10:12 AM
Get a Big Meat shim or something custom made by a tinkerer. You can't help it by getting a longer crank on the short leg side (hu, hu, he said "short leg") since this will help on the top of the stroke, but will hurt on the bottom of the stroke. A shim is the direct solution since it makes your effective leg length longer throughout the stroke.
Oct 30, 2002 11:04 AM
I would think a podiatrist might be able to help.
Be Careful!Anaerobic_Nut
Oct 30, 2002 11:21 AM
I have a leg length discrepancy which created back problems for me a few years ago. After visiting a good PT, we created a shim to correct the problem, which I continue to use. Many cyclists have dicrepancies, but their bodies compensate for them with no problems. So unless you have issues, don't change anything as you could cause damage. If so, then consult with a PT or someone in the cycling community who would have expert advice on what to do. Make sure you get your legs measured accurately. Also, isolated leg strengh training could benefit you as well.
I woke up this morning thinking, "shim the cleat!"BowWow
Oct 30, 2002 11:30 AM
Glad to know I'm on the right track. Thanks for the great advice!

By the way, Nick, my teenage kids call me "The Freak!" But for entirely different reasons...