Winky

I just bought a new touring bike, which the stork is dropping off via UPS next week.

I have a leg length discrepancy somewhere around 1.25 inches. I will get the specifics from my physio next week.

I just wanted to do a poll of what your best fixes are. So far I have been told that a shorter crank on the shorter leg is the best option. Currently on my city bike I have a second pedal zip tied to my existing pedal. I'm worried that a shorter crank could cause a different sort of imbalance?

I have never used clip in shoes, so I won't go that route, at least at first as I also have one tiny foot so clip ins would also involve two different sized shoes.

THANKS!!!

52telecaster

I am absolutely no expert on this but it seems to me that your current solution is better than the shorter crank arm version if the zip ties hold.

TimothyH

A shorter crank arm for the shorter leg will not help.

It will place the pedal closer to the saddle at the bottom of the pedal stroke but further away from the saddle at the top of the pedal stroke.


-Tim-

rhm

+1

I know an avid cycle tourist who has this problem, though perhaps not as extreme. I don't remember exactly what his solution is, but I believe it involves something like what is discussed in this thread (which I found by googling "bicycle pedal blocks for adults"):



https://forums.mtbr.com/general-disc...ch-903897.html

stardognine

Tourist in MSN

I agree with both TimothyH on different crank lengths and also with RHM on making the shoe sole thicker. But this probably would depend on what part of your leg is shorter?

If the part below the knee is shorter but the leg above the knee is the same length on both legs, then the taller shoe with thicker sole likely is the best solution. That way, both knees flex the same amount from top of stroke to bottom of stroke.

But if the part of the leg above the knee is shorter, you probably need a shorter crank arm to avoid flexing your knee too much, plus you probably need to have the thicker sole to compensate for the total length of the leg being shorter.

I have no clue if both arms should be shortened up, but that might be something that a medical professional could comment on.

Some communities have bike charities where people can donate bikes and bike parts. They often have bins of used parts. If you need to try several options of crank arm lengths, that might be the most cost effective place to look for crank arms.

CliffordK

A 1 1/4" discrepancy is pretty big.

However, I think there was an earlier discussion suggesting that you don't necessarily need to make up 100% of the difference. More like 50%.

Look under "Adaptive Cycling"
https://www.bikeforums.net/adaptive-...t-other-needs/

I'd go with @Tourist in MSN, and if the issue is more lower leg, go for pedal/shoe changes, and in the upper leg, consider the crank.

Or, perhaps a combination of both approaches.

Not all pedals are created equal. There are a few extremely thin pedal designs.

MT Zero ? Tioga
HT

The Tioga MT Zero pedals are very thin, but read the reviews, including the wide Q-Factor.

The HT EVO ME03 (or ME03T) are still mighty thin, but have much more positive reviews.

With the pedals about 1/2" thick (about 1/4" over the spindle).

Still, if you wish to add say 1/2" more, you'll need a pretty chunky pedal about 1 1/2" thick.

One step thinner?

The Shimano 600AX and Dura Ace AX pedals use a special crank, and external bearing, and drop design to give essentially ZERO equivalent thickness.

Probably best used with toeclips.

And, not cheap to setup. But, they could potentially last you a lifetime.

You might look at "Pedal Blocks". Although I think they're mainly designed for children's applications.

ThermionicScott 

My left leg is slightly longer than the right, and having its cleat slightly further back than the right helps a little. (An analogous fix with toe clips would be to use a cage for a larger foot on the side with the longer leg.) Chances are, you'd need to combine multiple small fixes to overcome a 1.25" difference.

79pmooney

I have a 1/2: discrepancy. My PT had me put 1/2" lifts under the heels of all my shoes or 1/2" additions to the sole thickness. When I showed her my cycling shoe I'd added the heel lift and a 1/4" plate to space out the cleat, she gave it a thumbs up. (She is also a very good and strong rider.)

For platform pedals and a 1 1/4" discrepancy, using the same math, a 1 1/4" lift for your heel that tapers down to 5/8" over the pedal. My PT didn't care whether the lift was inside the shoe or outside. I went both as I said on my cycling shoes, use heel lifts inside on most of my regular shoes/boots (cheap) and have a 1/2" addition to my sole on my most often worn pair of shoes. (Took it to a cobbler.)

Ben

CliffordK

Ben,

I'm surprised that a heel lift is effective with a cycling shoe, as the pedal rotates around the spindle, and presumably naturally compensates for the tall heel.

Adding the spacer at the cleat would be different, of course.

But, that could also work in reverse, and without the heel lift, one would naturally pedal toe down a little more.

Toe down pedaling may also be why @ThermionicScott indicated that cleat placement and toeclip size may affect leg length discrepency.

Winky

Reading through what this person recommended was super helpful! Thank you for sharing the link. My leg is similar, shorter both above and below the knee.

Winky

The leg is shorter both above and below the knee, I will get the exact measurements before I order any parts. I want to get my new bike as balanced as possible because I already have knee problems from years of not doing anything to even it out : - / The short leg is also missing a muscle so it will use any excuse to do less of the peddling!

I will look up these super thin pedals, thank you. And am reading through the adaptive cycling forum now.

CliffordK

I assume you're talking to an orthopedist. Perhaps you can also get a sports medicine consult (occupational therapist?).

One thing about cranks is that to some extent the body reacts to the circle circumference that the pedal spindle goes around.

So, a longer crank length, the more force/torque applied, but at a slower cadence.

The shorter the crank length, the less force/torque applied, but at a faster cadence.

Tandem riders sometimes use that to their advantage, so the Captain might ride 180mm crank arms to essentially slow him down, while the stoker rides 165mm arms to speed her up, so they find a happy medium where both are comfortable.

In your case, using a shorter arm, say 175 on the long side, and 170 on the short side will mean less force/exercise for the short leg.

In a sense, that may well be good for your situation, but on the flip side, the leg will get stronger with the more work you force it to do.

Oh, I find in my personal situation, the more I ride, the better the knees feel. I'm almost addicted to riding, and if I'm off the bike for more than 3 days, I can sure feel it in the knees.

Winky

I do have an orthopedist and proper orthotics, but most of the length correction is in the heel. I will ask what he recommends, he is the perfect person to ask! I also have a physio who I have not seen in a while, so will ask them too. So what you are saying is, that this is not a forum full of medical professionals?

Interesting / makes sense, I should do that for a year purely as a way to make the little leg stronger. Just kidding, but ok, I will definitely not do all of the correcting in arm.

Hahaha, knees are so bossy.

CliffordK

Most of us like to ride bikes. With varying backgrounds, and experiences.

I'm not saying to not change the crank arm length. But, just to understand that changing the arm length changes a bunch of things.

• Longer crank changes how far down the pedal goes (thus a lower seat)
• Longer crank changes how far up the pedal goes (flex at knee, knees to gut, etc).
• Longer crank means the pedal goes through a longer circle of rotation (so, for a constant speed of movement, a slower cadence).
• Longer crank has more torque on the crank (but perhaps you're just experiencing force that you're applying)

Shorter, of course being the opposite.

Anyway, that gives you some stuff to think about.

It is impossible for someone on the opposite side of the world to say what is comfortable (and safe) for you.

Crank arm lengths are often measured in 2.5mm increments, with common lengths:

155mm, 160mm, 165mm, 170mm, 172.5mm, 175mm, 177.5mm, 180mm, and most people hitting between 170mm and 175mm.

There is a lot of similarity between "square taper" cranks, and you may be able to even go with similar cranks from different brands.

More modern cranks are sometimes sold as singles on E-Bay, perhaps due to crash damage or replacements.

Anyway, if you have your bicycle, and wish to experiment, many cities also have a "Bike Coop" that sells spare parts cheaply, especially more standard stuff like used cranks (often singles), (standard) pedals, etc. You can spend a lot on specialty items quickly, so, there are benefits of running your experiments cheaply.

Winky

I live very close to a DIY bike garage called Bike Pirates and they have a huge selection of parts that people donate and are available at a low cost, so I will go there first for sure.

I have a good plan now. Consult ortho, scavenge for parts, get a proper fitting. Most likely solve through a combo of crank size, pedal shims/pedal size & insoles.

fietsbob

Shape of the pedal stroke is a oval with a pedal height or shoe thickness.. addition,

vs circular with a change in crank arm length ..

79pmooney

Clifford, the heel lift does nothing when pedaling, Its only function is to correct my discrepancy when I am off the bike.

Ben

stardognine

djb

I will be interested in hearing how the changes make a difference for you.
I suspect that informed, proper advice and possible solutions are to be found, as I am sure there are a fair number of cyclists who deal with this, and that there are very competent physios and sport medicine folks etc that have done all kinds of tests on this and have the proper insights.
I know that when I look into this, I will want to have confidence in suggestions.
Similarly, but probably different to an extent, the muscle issue plays a part in what I mentioned the other time, as well as foot position and rotation issues as well. We have had a custom made doohickey for years now, that helps with the foot direction issue, and so far, both pedals have been the same and I imagine compromises are made on both sides vis-a-vis seat height.

and yes, the two sets of shoes thing is the reality here also, and a factor for spd type shoes. I may one day keep an eye for clearout spd shoes for this, but given how well the riding has been over the last few years, I actually dont think spd would be necessary, also there would be the unclipping issue which could very well be a deal breaker (back to muscle thing).

good luck trying stuff and observing the difference and how much it actually helps, I'll be interested to read of how it goes. cheers

geoffs

They guy that is the best source of information is https://www.stevehoggbikefitting.com/index/ and the FAQ section which is free.
You're best bet is to see a bike fitter that actually knows what he's talking about. Go and see Mark Dwyre at T.I. Cycle | Treatment for your Cycling Obsession

Winky

My pedorthist said I should start by building up the pedal approx. half an inch (I already have some of the discrepancy corrected through an in-shoe orthotic) and that I should "play with the rest of bike fit to find the best compromise between the long and short side for the remainder of the fit parameters". Similar to what people have been suggesting. I found a shop that was recommended in Toronto for bike fitting and they seem to have confidence in addressing leg length discrepancies.

Ya, maybe proper cycling shoes will be next year's investment. I went cross country skiing this year and I had the hardest time clipping into the ski with my little foot.

T.I. Cycle is a bit far for me to go, but the other link geoffs included has a ton of good reading.

djb

the underlined part sounds very reasonable.
I figure the most important thing is to listen to your body about what feels best with various changes. I have a healthy scepticism of opinions by people who dont have an understanding of muscle differences that they possibly cant imagine how it is, but a really good physio who perhaps bikes also should have the best insights.

As your pedorthists says, the compromise thing should be good, my family member has done rather well so far with a compromise, although we still havent done the "slight pedal increase combined with a slight insert increase also" route.

ditto on the xc ski boot clip in, very difficult here also.

one thing for shoes is that with lots of riding, a shoe that has a stiffer sole generally means a more comfortable foot, because there isnt much shoe flex as you push down on pedal, so nicer for foot muscles, and more energy going directly to pedal also.

as you know having done some trips before, the amount we have to work schlepping a heavy bike along is a lot more than a bike with no bags on it, so this generally will show up fit issues, including seat height and all that. Riding regularly with bags on the bike is also a big help in slowly getting your muscles stronger from pedalling a 60lbs bike lets say, so always a really really good idea to ride loaded a lot before a trip, as it helps pinpoint fit issues, and you know, often just a slight change will make all the difference.

Winky

This is hopefully just a temporary solution, but so you can see the progress. I am going to paint the block of wood black to tone it down a little. Made by a Toronto bike shop.

fietsbob

Note the screws in the black pedal .. if you find that block height OK , a side plate pair

can be fabricated , that adds that height to the pedal ..


Now discontinued by French TA company .. Had a premium pedal
with alternative height side plates available..

Company is still around , just stopped the pedal making..