[uofabill]

I got a couple of questions. To start with I've had a couple of hip replacements and as a result my right leg is about 1" shorter than the left. When I ride long distances I get muscle pain in my lower back, at the belt line, on my right side. Happens on both my road bike and mtn bike.
I think it has to do with my uneven leg length?
I'm wondering about trying a shorter crank arm on the drive side. I am running 175 crank arms. I was thinking about putting on a 170 drive side arm.
Seems like I read a thread about this in the last couple of years.

The other question. This could be a pretty costly experiment. Does anyone know that the name of the sports medicine therapy group in Boulder? I have read/heard about them and my recollection is that they analyze your position on the bike and make changes in bike fit to remedy riding discomfort. If possible I'd like to get some professional guidance before spending the money for new crank arm that might or might not work.

Thanks
Wild Bill

 

[WR304]

Rather than odd length crank arms your best bet would be to try and build up the shoe on the short leg a bit if possible. This is a lot easier with road shoes than MTB shoes though.

You could try some washers under the cleat or stuff one shoe with insoles and take them out of the other shoe to even out the difference a little.

The problem with odd length cranks is that you lose a lot of power. If that's what it takes to ride a bike it's worth doing though.

My left leg is 1 inch shorter than the right and I can only bend the left knee to 90 degrees nowadays. I have a 175mm crank on the right and a 145mm crank on the left to try and even out the difference which works fairly well although it's not perfect. It also has the positive effect that your knee and hip don't have to move as much. That's very useful if you've got bad joints.

If you're thinking of going down the shortened crank route it's generally cheapest to get a normal cheap solid 175mm crank and have it drilled and threaded to the exact length you need. It needs to be done on a proper jig to be lined up properly.

In the UK try Highpath engineering who've done several for me in the past. It costs about £20.

http://www.highpath.co.uk/

Hope that helps.

 

[FreeRangeChicken]

The Boulder Center for Sports Medicine does bike fit stuff as well as LT testing, VO2 max, gait analysis, etc for all kinds of pro athletes. They are very well known in the Boulder sports community. I would highly suggest talking to them before popping for a set of cranks. BTW, a 5mm crank difference may sound small but it is pretty huge. Call BCSM and talk to them. This type of problem should be right up their alley.

[edit]
They may recommend shims or spacers rather than differing crank arm lengths which creates a leverage imbalance.
[/edit]

FRC

 

[uofabill]

That's the name I was looking for,

Thanks mucho, that's the outfit I had heard about. I think you're right, they can probably get me headed in the right direction. I don't know if this is something that could be done long distance or if I'll have to make a trip up there so they can diagnose the problem first hand. I'll get hold of them and see how it goes from there.

I have thought about putting some kind of spacer under my right cleat or maybe as thick an insole as I can use in the shoe. The thing about a spacer under the cleat is that it will make the cleat protude below the lugs of the shoe quite a bit. Maybe that's not as big a deal as I think? I suppose getting a built up shoe is also an alternative and may be what has to happen.

Thanks again for the info.

 

[WR304]

I have thought about putting some kind of spacer under my right cleat or maybe as thick an insole as I can use in the shoe. The thing about a spacer under the cleat is that it will make the cleat protude below the lugs of the shoe quite a bit. Maybe that's not as big a deal as I think? I suppose getting a built up shoe is also an alternative and may be what has to happen.

If you can get away with it the insole idea works a lot better than spacers under the cleats. Spacers affect how you pedal more and a lot of them can make your foot unstable on the pedal. Very offputting.

You can get custom made carbon shoes where they make the shoe sole to the specified depth which could work for the road. There's not much offered for MTB shoes though.

Spacers on MTB shoe cleats sounds like a nightmare but I've never tried it myself. It might be ok but it's unlikely.

 

[Sprocketeer]

I wouldn't go a whole 5mm.

I used to be a ski technician and specialized in boot customization. So here's my expert--though not really scientific advice.

First of all, unless you're very tall and likely riding an 18" + frame I wouldn't recommend the standard 175mm cranks in your case anyway. They put long cranks on bikes as a one-size-fits-all sort of solution that allows you to turn the drivechain with the least force (leverage). On women's specific bikes these day's they're going with a standard length of 145mm because 175mm is obviously too long for an American or European woman of average height. Before going as short as 170mm cranks however, I would see if I could get my hands on 172.5 mm cranks. 5mm is a bigger change than it seems. Regardless, I would keep both cranks the same length.

As for the different leg lengths, I'd really have to see you in person to know if the hip replacement changed the actual or, particularly, effective length difference in your legs. There are a lot of people out there who fall for the old 'one leg shorter than the other' diagnosis.

I'm not saying this because I think chiropractors (sp?) are quacks--far from it--but rather based on the experience of dealing with professional athletes who have, for example, had their entire ankles replaced with titanium hardware after breaking them so many times. (literally, it's like there's nothing between the leg and foot but a bridge of skin--no bones, nothin')

Building up the shoe is an excellent idea, and you wont believe how easy and cheap it is to try it at home. Try an insole first to build up that particular foot--Dr. Scholls will do and you can cut it if you only want the build up in the front. You could also try putting a heel lift in the OTHER shoe to even things out.

Of course, if these simple solutions don't work, or your just curious, go to a foot (sp?) specialist--a real doctor who specializes in this, NOT a chiropractor. He might just say to you, "What problem?" or he'll set you up with a custom pair of "Orthos" insoles which requires a foot mold (and you can use these in any shoe or boot from then on).

Hope this helps.

 

[WR304]

If you're getting back pain have you got a sole raise in your normal everyday footwear?

The leg length difference throws all the muscles in your back out of alignment when standing. If you haven't got some already your Consultant should be able to refer you to the Hospital orthotics department where they can modify a pair of normal shoes by putting an insert into the sole.

 

[uofabill]

Street shoes

I do have a heel lift that I use in all my street shoes and it helps. It is a 1/2" lift that I got at an orthopedic shoe store. That guy measured my legs and confirmed that the right one is an inch shorter. When standing the heel lift helps keep my hips level. I had some sciatica and the heel lift has helped that.
I can tell a lot of difference in the levelness of my hips with and without the lift and I don't get the same back pain that I get when riding when I'm not riding.
I'm going to find some thick hard felt and try to put it in the front of my riding shoe and see if it helps. That makes more sense to me than trying to put a spacer under my cleat. The extra space I would need would make that a really awkard arrangement. I can envision all kinds of problems with a cleat protruding down that far below the sole of the shoe.
The thick insole is in leu of getting a custom built up ortopedic riding shoe. I suppose I should just bite the bullet and spend the money and get a riding shoe built up.
It seems to be the consenus that having different length cranks would not only be hard to get the right length but would have a negative effect on pedalling power/efficiency. When I think about it, that makes sense.
Thanks for your input.
Bill