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Wanting to clip in but have a short leg (3.5cm shorter than the other)
Well, have been inspired by Trev's thread over here http://nobmob.com/node/13306 but have a problem (which I'd kind of forgotten about!)
My right leg is 3.5cm shorther than my left. I had platforms put onto my bike when I bought it because of it, but now I'm thinking of clipping in, I'm wondering if there's anything I can do.
With my current riding shoes, these are just an old pair of trainers which I have my shoe man slice off the sole, insert 3.5cm of fill, then stick the sole back on. Works well for trainers and has done for 10 or so years.
I called into a bike shop near work and they thought I maybe able to put a longer crank on the left hand side. Can't actually get my head round how that might work though?? Longer pedal stroke on one side, pedal will be lower on that side when at bottom dead centre and higher when at tdc.
So, anyone think of anything which might help? I don't think it's really feasible to cut off the bottom of a cycle shoe, stick in something, then stick the sole back on.
I guess it's not the end of the world, but I'm thinking of doing some races in the future and if I start looking at longer races I'd really like to conserve some energy where possible and clipping in might give this to me.
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hmmm
block of metal drilled through, long screws for the cleats and attach block and cleat to the bottom of the shoe?
but I had a gym (spin) class and the instructor was clipped in and she said she had one leg shorter than the other, dont know by how much. Anyway, she just set the seat height so that it was comfortable for the shorter leg and I guess she has gotten used to the rotation
I would strongly suggest investing a proper bike fit by a company like http://www.hert.com.au/main/page_bike_fit_bike_f... it is totally worth the money, for less then the cost of a set of light wheels or a really really stiff frame you will, improve performance, and reduce injury LONG TERM, once your are clipped in the stresses placed on your hips & spine.
i thought it said mm not cm..
I was reading an article in Bicycling australia that talked about pedaling afficiancy in the article the author's suggested that the majority people have one leg shorter than the other to some degree. He also stated that he estimates 99% of riders should use shims and wedges with their cleats to get a better fit. Whilst not everyone has a difference of 3 to 4 cms between legs in principal the use of shims and wedges could work for you Im guessing.
Put a longer crank on the side with the longer leg. This will take up 2.5cm of the 3.5cm your are dealing with.
The problem with poor bike fit in this situation generally comes with over straightening of the leg at the bottom of the pedal stroke. Your ankles knees and hips are designed to bend to shorten but when you have to reach to far you will tilt your pelvis in relation to your spine which will on long rides cause lower back pain. The over straightening of the short leg will lead to problems with the joints on that leg. Using a shorter crank arm on the side with the shorter leg lets you extend that leg to the correct length. The longer leg will not straighten completely either because it will be about 1cm short of full extension, that's not a problem as far as joints are concerned although you may loose a little efficiency. If you shim the shorter leg as well as using a shorter crank, you might be able to work it so that both work out to be the most efficient length. You could shim by putting spacers between the cleats and the soles of your shoes, pedals remain unchanged. You may need to source longer bolts to allow you to do this.
Visiting a bike fit specialist is also a great suggestion.
Cool, thanks for all the replies.
Justin, wood or some sort of hard plastic might be the go, but then it will make it almost impossible to walk if and when I have to. I have stuck some plastic between my skis and bindings and this works a treat. Yeah, I think almost everyone has a few mm different from one to the other my case is a bit extreme and really only came to light about 10 years ago when I started getting really sore backs. Now I look back on some old pics from primary school it's quite obvious, better late than never I guess.
Christoffa, live and learn. Didn't know this kind of thing was available. I will look into this, thanks.
Adrian, yeah I expect mm I could live with or even not know about.
Spud, that doesn't surprise me although I can't picture that amount of shim and wedges.
Again, thanks for your replies,
regarding having a longer crank on the left, I just don't think the mechanics of it will work and I might just have to clip in and put my seat height somewhere in the middle with some (perhaps not the full 3.5cm) wedges/shims on my right shoe. While not optimal, if I want to clip in, it might be where I have to go.Started editing this before reading Kit's message.
Kit, thanks for that. I want to think that if I can get to within 1cm, I will be happy to have that as a compromise. So my question is, what is the effect of having a longer crank than I have now? More leverage?
This thread had several people that could maybe help with the best way to setup the bike? http://nobmob.com/node/13348
Get some advice from the guy for whom this sort of stuff is bread and butter - http://www.cyclefitcentre.com/about%20us.htm
If he doesn't know what you need to do, nobody will.
There really is only one name in Sydney: Steve Hogg.
Cranks don't really come in 3.5cm shorter or longer varieties, do they? Anyway, you will at least get 15mm difference, I think, which is something useful.
I'm thinkin the longer pedal should be 17.5 mm longer than the other pedal. Not 35mm
When the pedal rotates ,the total height from top to bottom will add up to 35mm
correct me if i'm wrong, just a thought....
... but the longer/shorter crank combo has knock-on effects that may render it unsuitable.
Steve Hogg will know what to do. He is the closest guy I know to a medical bike fit specialist, which is what this matter is. He also sees a lot of pro and Olympic level riders who spend up to 24 hours non-stop in the saddle, and offers a refund-if-you-re-not-satisfied guarantee. Sure, not cheap, but good help never is.
Different sized crank arms would mean that when the cranks were at the bottom both legs would be properly extended. However when the cranks were at the top the longer crack would mean that that leg is significantly bent compared to the other shorter leg.
The physics would also mean that the longer crank = large moment arm, therefore you wouldn't need to pedal as hard to get the same torque as you would on the short leg. This would mean that the shorter leg would have to work harder to produce the same torque.
If you were able to put spacers beneath your shorter leg's shoe it would result in the leg becoming longer and things would be like normal, except for when you would have to walk!
I would look at getting your shoe permanently modified and keep the bike cranks the same length. This means walking will be normal as well.
Great, food for thought. I think at the least I will make contact with Steve Hogg. I'm not planning on becoming any kind of super cyclist and really only want to get out there for health and fitness but also perhaps push myself for some longer races when fitter. This may well mean in the long term it's worth it, but right now if I go the whole deal it might cost me 1k (including pedals and shoes) and I can't see that happening right now.
That's kind of what I was thinking re the longer crank on the left. I just couldn't picture it working correctly. Right now, my right foot is only doing smaller rotations because of the build ups but my right knee is doing similar rotation as my left I think. For some reason, finding this hard to picture.
Yep, that's what made me start this thread, it's not as easy to slice off the bottom of a cycle shoe and move the clips etc as a pair of trainers. I am extremely used to walking with the build up and it's uncomfortable(back wise) for me not to have them now for any length of time which I can tell you took some getting used to go bare foot everywhere.
Again, thanks all for your input.
Similar to what Justin up the top said, get block of good timber the required thickness and some longer screws from hardware/bolt store and extend the cleats. At least that wont set you back much money if it doesnt work.