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Knees,knees, and more knees!(3 posts)

Knees,knees, and more knees!peaches
May 22, 2002 2:36 PM
I have been experiencing strange vibrating and grinding sensations in my knees on and off for a while now. The physical therapist could not find anything structurally wrong with my knees and I am not deformed at all. Speedplays have helped but the problem still arises with every ride. Does anyone think an incorrect B.B. spindle or crankarm length could be linked to this sort of problem? I live 50 miles from my nearest shop and don't get to visit them all too often, but will be asking their opinion as well upon my next visit. If it matters, I ride a stock 57 cm. Serotta CSI with a 172.5 crankarm length. BB length unknown.
Well Peaches, I imagine you are a female on a bike that is setupPaul
May 23, 2002 3:48 AM
for a male. Your problem is common for a lot of riders who don't know how to fit themselves to a bike. The bike should fit you, not you to your bike. Colorado Cyclist use to have a good fit writeup, check there for info. I use the Greg LeMond fit setup (what CC uses). It's a long explanation, and I would go into it if you can't find it on CC. But it tells you how to measure your inseam for correct seat height, fore/aft position, stem lenght,stem height, etc. Any of thes factors could cause discomfort when on the bike. You have a lot of float with the Speedplays, but your cleat position could be off. I make sure the cleat is positioned right over the ball of my foot. I'm sure the BB is not your problem. Are your shoes properly fitted? Not too tight? If there is nothing wrong with your knees, then it's the bike setup.

I suspect you have incorrect seat height, fore/aft position. Crank length shouldn't cause knee problems. This is a factor in spinning, and climbing.

Let me know how you make out.
re: Knees,knees, and more knees!simstress
May 23, 2002 8:03 AM
Next time you're at your shop, ask someone to set you up on a trainer to check your fit. The Q factor (basically, the distance between the pedals) might be narrow for you. Is this the first season you've experienced this? How long have you been riding? Do you tend to spin high cadence or mash big gears? Are you climbing lots of hills?