knee problem



cldpsu

New Member
Nov 2, 2003
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hey what's up everybody,
I am feeling a little discomfort on my right knee whenever i go riding... i don't know what it's from. Could the position of my foot on the pedal be causing this discomfort? Also, my left heel is a lil further from the chainstay then my right, so my left knee comes is closer to the frame as im pedaling than my right, do both legs have to have equal distance?

Thanks,
Cristian
 
Originally posted by cldpsu
hey what's up everybody,
I am feeling a little discomfort on my right knee whenever i go riding... i don't know what it's from. Could the position of my foot on the pedal be causing this discomfort? Also, my left heel is a lil further from the chainstay then my right, so my left knee comes is closer to the frame as im pedaling than my right, do both legs have to have equal distance?

Thanks,
Cristian
Well, there could be a million causes for this, and you may need a real expert to figure out exactly what's wrong and how to correct it -- still, I might as well say it before someone else does:

What sort of pedal system are you using, and how did you determine your cleat positions? I did a search here on CyclingForums for "cleat" and "position" and turned up about 50 threads; it's a complicated subject. Sometimes the "center the pedal at the ball of your foot" rule isn't good enough.

The issue may also be related to float, depending on the pedal you're using and how you have it set up. If your legs aren't falling symmetrically alongside your chainstays, that could be as much about your own personal biomechanics as anything else. Having a pedal system which allows your knee to compensate naturally may be just what you need.

Anyone have any good cleat position links?
 
thanks for the reply,
I am using SPD pedals.. and i determined the position on my feet by just playing around with how close i wanted my heels to the chainstay... not much i guess=(
 
Hmmm... if you've got a local shop that you buy stuff from, particularly if you've bought your bike and/or pedals from them, I'd go and chat with them. Most shops are more than willing to assist with matters of fit, which is what this probably is.

I'm thinking the first thing you need to do is find out a little bit more about cleat placement. There are some really elaborate standards out there for how to position your cleat based on the direction your feet naturally dangle, how they fall when you walk, and how they tend to twist or turn while you pedal.

Hopefully someone here knows of a good online resource. Either way, try to see a pro and explain the problem if possible.

As I suggested before, you may want to do some basic research into pedal systems that offer more rotational float. I know my legs don't dangle and move without some weird twists and bends in them, but my Speedplay pedals are more than accomodating. Classic SPD systems tend to be a bit rigid; your legs might just need a little more room to twist as you stroke.

In your original post, you questioned whether your legs needed to hang equidistant from the stays; they answer is no, although that'd be nice. Human legs just aren't that precise. You need a bicycle setup that gives your natural imperfections a bit of forgiveness, and more float is often the ticket.
 
Knee pain can go beyond just cleat placement. The asymmetry of the pain does not necessarily imply an incorrectly positioned foot. Other parameters that create pain in one or both knees are the saddle to handlebar distance, saddle height, and crank length. (Saddle angle has some effect, but only in fairly extreme positions. If you have the nose up, your hips ride more to the rear of the saddle, effectively extending your leg length, and vice versa.)

I would recommend adjusting the saddle position first. It is easy to do and requires no additional equipment. If your saddle is too low you can get significant knee pain; knee pain from a saddle too high is less likely as you'll probably notice the rocking motion of your hips on the saddle and reduce the height before you hurt your knees. Similarly, if your saddle position is too far back you can create knee pain (too far forward rarely occurs with the greater set-back of most seatposts).

As for height, a typical starting point is 0.883 x inseam (this is the BB to the top of the saddle, going parallel to the seat tube. As for the saddle to handlebar, there again are many formulas. I typically end up adjusting the saddle so that the front of the saddle is about 1 to 2 cm behind a plomb dropped to the BB. The actual distance to the handlebars is a function of the stem length, the top tube length and the saddle position, all of which will be affected by your riding style and flexibility.

The classic cleat position is to have it so that the pedal axis put opposite the ball of the foot. But there are some who advocate moving this slightly forward of the ball. More important than this slight tweaking is having sufficient float. The SPDs have 6 degrees which is pretty good for most people. (I've had knee surgery and anything less than 3 degrees gives me pain.)

Crank length would be the last to address as it would require additional equipment (ie, another crank of a different length) to test. Formulas for me indicate anywhere from 172.5 mm to 185 mm, which covers a ridiculously large range. In practice, 175 to 180 feels best. A starting value to consider is about 20% of your inseam length.

The inseam length is therefore an important value to try to measure accurately to help you get started. It's easier to measure if someone helps you. Stand with your back against a wall in your stocking feet. Place a hardback book between your legs, with the spine parallel to the floor and against your crotch. Lift it as high as you can comfortably place it. Make sure that the edge that is against the wall is flush to the wall, in order to ensure that the spine is level to the floor. Measure from the ground to the spine.

Good luck, Robert