Sizing for unequal leg length?
 

My right leg is 1" shorter than my left. When using platform pedals, my right foot is typically parallel to the bike frame, but the left foot typically toes out with the heel closer to the frame. When sizing the seat height, should I use the short or the long leg for "full extension at bottom of stroke?" I have size 13 feet, and the foot extension can partially compensate, but for the best comfort, what do you recommend?

Thank you - FH

This thread provides several links you may want to explore:
http://www.bikeforums.net/fitting-yo...rm-length.html

The links are about leg length difference that are within the normal human difference, up to about 1/4 inch. Like the OP, mine is far more than that due to an injury. I am not hardcore, but I do 25-30 mile off-road rides a couple of times per month. I adjust my seat throughout the ride with my dropper, because too low makes for patella pain and too high makes for other leg pains. And, with my differences I am shooting to find a happy medium. My road bike never seems to cause issues, but my rides are usually under 3 hours due to a fused neck and my neck muscles giving out.

Either way, a little knee irritation is a lot better than coach surfing.

Hi [MENTION=210172]Ronno6[/MENTION] -

I looked at the thread & it's mostly about using cleats to compensate for minor differences and better power delivery. As with Mr. [MENTION=395421]Kindaslow[/MENTION] - my leg is a full inch shorter on one side due to an old injury. I don't use cleats because of the radical variation in how my feet are situated on the pedals. To compensate with crank arm length, I'd need one arm a full 25mm shorter than the other.

I was hoping for some options, but I think that ultimately, like Mr. Kindaslow, I'll just need to compensate by moving around on the seat and periodically lowering or raising the seat height to favor one leg or the other. And words of wisdom: "...a little...irritation is a lot better than couch surfing" - YES.

Had the same problem
 

Right leg 3/4"shorter so I sat what my wife described as almost side saddle. I always sized up on the right leg at full (knee slightly bent) extension. Since I was favoring the right side, I think I took up a bit of the slack on the left leg. I always pedaled with right heel and toes actually off the pedal in about a 2 o clock position.

I did use a somewhat large saddle that had sufficient room to support my butt on the right side since it was off center.

Never had any real problems other that a sore butt after 20-30 miles. Would then stop and dismount for a few minutes every 5-8 miles.

Hip surgery realigned my body and now have equal leg lengths, but I never regained the strength I once had in my once shorter right leg.

Good luck.

Thanks [MENTION=162673]okane[/MENTION] - I'm able to use both OK, but I do have to do some rocking over the seat to do so. I've installed a Brooks B135 saddle and the springs seem to help me.

Short Leg gets a thicker shoe sole and a Shorter Crank arm. how much I Cannot say .. Sports Orthopedics is that Niche in the Professions..

If I recall correctly, the OP doesn't like clipless. That actually works in his favor here as I would think it more common and less expensive to find Leg Length Discrepancy (LLD) corrective shoes in casual or athletic styles than cycling specific. That may not be a complete solution as there may still be differences in hip position or femur length and thus knee placement and extension. You could try a 165mm crank on the short side and 175mm for the longer leg to gain about 3/8" of extra extension for the longer leg, but I really have no idea how awkward two different length cranks would feel or if it would create other problems. Might be an improvement, might not.

In the interim, I'd think that setting saddle height for the shorter leg would be preferable as a bit of under-extension of the long leg is less likely to cause problems than over-extension of the short leg. Neither is good so seeking the council of a good sports ortho communicating with a bike fitter will likely result in the best solution.

Just a thought but could a crank be re-drilled and tapped at the appropriate length?

It already is .. Kiddy cranks on Treks Wee Bikes have 2 sets of holes machined in them , IDK how well that will hold up under a 300 pound adult.

I would get a replacement crank arm as long as possible, fill the peddle hole, re-temper it, drill and tap it 25 mm shorter. Make sure you have enough edge distance from the end. I would also heli coil it. Find a old school machinist and it will be easy.
Cheers,
David B.

It seems like if the legs are close in length, the crank length should be the same. The problem is that the one of the pedals needs to be moved up to the shorter leg, and a shorter crank does not do that, it only makes the pedal circle smaller. A shim would move the pedal circle. That could be just a thicker sole on the shoe, or a built-up surface on the pedal.

If you use platform pedals, you can probably attach some thing to make the platform 1" thicker.

Wide rubber band holds wooden blocks on Pedals for Children. , but counter sink Wood screws between 2 wooden blocks would work too.