I'm not sure what you mean by "Speedplay shims". Are you talking about the shims from Speedplay to support the base plate of the cleat to better align with the contour of your shoe? Or maybe BikeFit leg length shims? BikeFit wedges?

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Travis Rassat
Vector Cycle Works
Noblesville, IN
BikeFit Instructor | FMS | F.I.S.T. | IBFI
Toughman Triathlon Series Ambassador

The leg length shims. Bikefit is one of those aforementioned companies selling shim (not shims) packages one shim at a time.

Speedplay also offers a 5mm shim now, in addition to the 3mm shim. You can also take two of the BikeFit wedges and flip-flop them to create a 1.5mm shim. I don't think that necessarily answers your question, as there isn't a variety pack available.

The other things to note are the screw lengths and if you're using the walkables, which use a different screw. It's kind of hard to get everything dialed in without having a variety of stuff available.

How much shim do you think you need?

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Travis Rassat
Vector Cycle Works
Noblesville, IN
BikeFit Instructor | FMS | F.I.S.T. | IBFI
Toughman Triathlon Series Ambassador

HI Travis,

I have a functional leg length discrepancy with my right leg. I've inadvertently stumbled on some issues through ski boot fitting/alignment processes that has sparked some "a-ha, eureka" thought with respect to cycling fit issues. The boot fitter I use is pretty well known in skiing circles and through their processes they have found that about 80% of their customers have more valgus in the right leg than the left leg (if I remember correctly, something about tibial twist).

I wonder if this same valgus causes this left psoas issue that many people have?

If I develop saddle sores, it's almost exclusively on the right side (mostly where the leg meets the groin).

I am thinking about a shim in the 3-5mm range.

Thoughts?
G

This is getting a little deep (disclaimer: I'm not a clinician or biomechanist by any means, but always studying, observing, and learning). I have read something to this effect before, in which there are trends in natural asymmetries, although I don't think these can always be attributed to a specific, single cause, but instead are more indicative of a series of things happening. It's a bit of a "chicken and egg" conundrum, and there is a subtle difference in stating "the right leg is functionally shorter than the left" versus "the left leg is functionally longer than the right." The pelvis is very rarely symmetrical. With all that said, I haven't really tracked these trends in the studio. I should - it would be fascinating, if anything.

What did your ski boot fitter do to accommodate your LLD?


Maybe - it's all a delicate balance. If you really want to dive deep, check out the book "Anatomy Trains" to get an interesting view of how everything is interconnected and held in balance.


Because we're all asymmetrical, we often adapt and can deal with our natural asymmetries, within reason. The right side saddle sores are the actionable item here, and I think you're developing a valid hypothesis, but I am going to be cautious with my suggestions without actually seeing you on the bike in person. I would say a 3mm shim is worth a try, but I would also want to see how your knees travel, what your foot structure looks like, how your foot behaves under load, etc. The functional leg length difference could be at the foot (i.e., greater arch collapse under load on the right), within the joint alignment, or muscular imbalances.

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Travis Rassat
Vector Cycle Works
Noblesville, IN
BikeFit Instructor | FMS | F.I.S.T. | IBFI
Toughman Triathlon Series Ambassador

The reason they don't come in a variety pack is because leg length is not something that is normally self diagnosed, certainly not accurately, so they are assuming an Ortho has told you what size shim you need.

If general knowledge, the average adult's legs can varied in length between 0.2 and 0.6 inches and is considered normal. Most people don't notice a problem until it gets around 1 inch or more, which is when limping and gate change occurs. I have a left leg that is about 3/4 of an inch shorter than my right leg and it causes me no noticeable problems.

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"...the street finds its own uses for things"

Travis,

Ski boot fitters don't usually pursue leg length differences when it comes to boot fit. Their alignment process usually involves means to get the ski base flat to the snow (no longitudinal tilt of the ski). They usually do this through canting with plastic wedges (either the boot and/or the binding).

Cheers,
G

Between an exceptional fitter or Ortho, I'd go with the fitter in terms of rectifying fit issues on the bike. I have visited two different orthos for PFPS issues in the past and talked to others. Neither one were very helpful and one of them was a triathlete himself. Helpful, in the sense of them asking me questions about bike fit, shoes worn, running techniques, etc.

Of course YMMV.

Me doing my own research has yielded more insights about functional symmetry issues than any ortho I've talked to or visited (my experiences). I have read a fair amount of Steve Hogg with respect to bike fit experiences. His methods and processes seem pretty reasonable to me.