Leg length difference pain

Jake Barnes said:

My right leg is a little shorter than my left leg (a few centimeters). I get severe pain in my
lower right back while riding, which I am assuming is due to my right leg being a little shorter.
Is there a way to remedy this problem? I am hoping that there is some sort of spacer that I can put
between my shoe and cleat-- once I get clipless pedals (I have standard toe cages now). Is this an
option? And, I am very open to other ideas as well.

Thanks-- Jake

You can add a shim to the cleat if you want or try an insert in just one shoe.

hth, Don

You could get the next length longer left side crank, which shouldn't be too expensive, then lower
the seat a bit.

Yours,

Doug Goncz, Replikon Research, Seven Corners, VA users.aol.comDGonczOpen ↗ If a computer won't do
what needs to be done, lie to it. Don't try this trick on people.

Jake Barnes said:

My right leg is a little shorter than my left leg (a few centimeters). I

get

Quoted message said:

severe pain in my lower right back while riding, which I am assuming is

due

Quoted message said:

to my right leg being a little shorter. Is there a way to remedy this problem?

With identical muscle fibre in each leg, a different crank length would be justified on leg-length
grounds alone (without addressing the "reach" issue directly).

If you are on a 170 at the moment, work out what your crank-length factor is
w.r.t. the shorter leg then use this to work out what the longer crank would be at this ratio.
Bearing in mind the easy-to-get cranks are 170-180, if you are nearer the 180 at the moment
then do the opposite calculation.

This correction you will get "for free" Indeed you will even out leverages and muscle contraction
speeds on each leg. You might feel you can sneak an extra 5mm on cranks on top of that adjustment,
then get some more via a shim and leave a bit of discrepancy over.

For example with a 4cm discrepancy you could try 170-180 on cranks, 2cm on shims and have each leg
5mm off it's ideal stretch. I don't know how deep the shims come, but you could use one Look pedal
and one Speedplay pedal.

Andrew Bradley

Andrew Bradley said:

With identical muscle fibre in each leg, a different crank length would

be

Quoted message said:

justified on leg-length grounds alone (without addressing the "reach"

issue

Quoted message said:

directly).

Quoted message said:

If you are on a 170 at the moment, work out what your crank-length factor

is

Quoted message said:

w.r.t. the shorter leg then use this to work out what the longer crank would be at this ratio.
Bearing in mind the easy-to-get cranks are

170-180,

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if you are nearer the 180 at the moment then do the opposite calculation.

Not quite so simple since any shims will count as extra leg length. The calculation will be more
complicated - unless we work to a cranks proportional to femurs scheme...

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This correction you will get "for free" Indeed you will even out

leverages

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and muscle contraction speeds on each leg. You might feel you can sneak an extra 5mm on cranks on
top of that adjustment, then get some more via a shim and leave a bit of discrepancy over.

For example with a 5cm discrepancy you could try 170-180 on cranks, 1cm on shims and have each leg
1cm off it's ideal stretch.

Oh well t'aint an exact science.

Andrew Bradley

I think you should put the extra spacer under the cleat (they are available somewhere,
hopefully somebody tells where) and, if possible, also use extra thick insole in that shoe
(this is what I do).

Also, if the thigh is shorter, you could try to move the cleat a little forward and, on the other
shoe, backward.

I have tried a longer crank on the other side, but I didn't like it very much (because of the
different "gearing", I guess). This is also somewhat expensive, if you have many bikes.

If you want to avoid serious back troubles (when older) use the thick insole all day long in
everyday life.

Heikki

" Doug Goncz " <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

You could get the next length longer left side crank, which shouldn't be

too

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expensive, then lower the seat a bit.

Using different crank lengths is not a good approach to differential leg lengths. The shorter leg
works harder. Normal practice is to shim between shoe and pedal or use an adjustable pedal such as
the TA Orthopaedic model.

--
Andrew Muzi yellowjersey.orgyellowjersey.orgOpen ↗ Open every day since 1 April 1971

A Muzi said:

Using different crank lengths is not a good approach to differential leg lengths. The shorter leg
works harder.

Until yesterday I thought the idea was 100% bad - both legs would not have the "right gear".

But then at the moment, his longer leg is likely "pushing harder" as it is on a relatively shorter
crank (This is two half-cyclists rolled into one
🙂)
Not only that but the long leg is presumably working in "too bent" mode which will reduce leverage
at the knee even more.

I don't suggest using crank length alone. But making up a two inch discrepancy with a two inch shim
doesn't seem ideal. Not only would the lower leg feel strange but the knee on the shimmed side will
come up higher and bend a little more too. So crank-length could play a useful role.

Another small increment towards a solution might be to move the cleat back on the long leg and
forward on the short.

I've heard of mad fools using just crank length and being satisfied with the fix, I've known people
be satisfied on just the shim effect.

Maybe the OP can grab a different crank and report back. With the cranks he'll find he won't do
much harm.

I once did a season on mismatched cranks as did a team mate. I felt wrong but didn't know why. He
seemed OK till I pointed out his discrepancy (on the start line) . He went straight out the back

Andrew Bradley

I shattered my left femur back in '97 & now my leg is like 3cm's shorter.

I use 170 left & 175 right cranks. & have my cleat built up around 15-18mm, I have experiment with more cleat height but you get the ball of the foot in the wrong position.

When out of the saddle it felt like I was pushing away from the pedal. By lowering the cleat height slightly I have found a happy medium. I set my seat height up for my bad leg as the right will compensate slightly for the little difference there is.

I mad the stack out of fibreglass. I find this ok now. I race A Grade club level here in Aust & race B Grade national track. I have only officially made my comeback to fulltime race in the last 12 months. With this above combo I find it ok. I have been racing bikes for 15 years now mostly at the A Grade level.

Cheers

imabuff1 wrote: I shattered my left femur back in '97 & now my leg is like 3cm's

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shorter.

Sympathies

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I use 170 left & 175 right cranks. & have my cleat built up around 15-18mm, I have experiment with
more cleat height but you get the ball of the foot in the wrong position.

And having lost femur, adding a lot of shim is going to really disturb the upper-lower leg balance.

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I mad the stack out of fibreglass. I find this ok now. I race A Grade club level here in Aust &
race B Grade national track. I have only officially made my comeback to fulltime race in the last
12 months. With this above combo I find it ok. I have been racing bikes for 15 years now mostly at
the A Grade level.

Good stuff . I can see why you sought out the optimal solution rather than just go for shim. What
with those 3cm coming directly off the femur (and thigh muscle?) I'd have wanted to test 170-180 too
(did you?).

Andrew Bradley

Have not tested the 170-180 cranks yet, weather has been rather crappy here. Raining all the time. But will hopefully get to test this out shortly.

Cheers

imabuff1:

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Have not tested the 170-180 cranks yet, weather has been rather crappy here. Raining all the time.
But will hopefully get to test this out shortly.

Twenty years ago you could have also tested negative shim on the longer leg. Some reported that
negative shim felt better than no shim at all even when used on both legs.

I am of course talking about the Dynadrive crank/pedal. I did see one of these disintegrate though.

Because of the foot stability issue you mentioned I would go for the lowest stack-height possible as
a "shimming base" (if money is no object) If you can cope with two different clipping systems you
might even mix pedals.

Andrew Bradley