Bike Fit Question - Leg Length Discrepancy

[Triskeliongirl]

I will say it one last time. Shims cannot be used to effectively correct a 1 inch LLD. Shims are great for correcting smaller LLDs, on the order of millimeters, as are some of the other techniques mentioned. The reason is that with a large shim, while your leg can be the correct distance from the pedal (and knee angle) at say the bottom of the pedal stroke, at the top of the pedal stroke, its like having a crank that is an inch too long and will raise your knee too high and cause a sheer force on your knee. I too worked with local fitters, got shims, got the idea to try different length crank arms, and contacted Lennard Zinn to obtain some. He immediately referred me to Tom Slocum of High Sierra Cycling. His dropped pedal system is ingenious, because it continuously adjusts throughout the pedal stroke so you are always the perfect distance from the crank arm. http://www.hscycle.com/Pages/cantsandwedges.html
He then offsets the chain rings to balance the leverage throughout the pedal stroke. He is an engineer that specializes in this, and has done work for several elite cyclists (olympian alexi grewel for example). I highly recommend him.

FYI, my 3 cm LLD was caused by a cycling accident. Like you I lost bone. In my case one sit bone is shorter than the other, and one of my hips is twisted relative to the other after my pelvic, hip and back fractures healed. The end result when I sit on a bicycle seat is that one leg hangs down 3 cm longer than the other. But, with Tom's system I feel biomechanically normal on the bike, better than I do walking even with shoes that are fit with lifts, etc. (which is also imporant though!). I'll never run again but I can cycle like a normal person. I also think my brooks saddle helps, since it accomodates the asymetry in my sit bones well (marks are deeper on one side than other).