Why do my knees hurt when I use 170mm cranks?
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Why do my knees hurt when I use 170mm cranks?
I'm 6' tall with long legs for my height. I've never had knee pain when using 175mm cranks but 170mm does it every time (eventually, sometimes after a few days of riding the bike), even with the seat raised to compensate. Am I doing something wrong here?
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Everything else the same except crank length? Shoes, cleat position, pedals, Q factors, etc.?
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Yeah, no kidding. You are 6' tall w/ long legs and you are using shorter than normal cranks? Go back to what works. Durrrrrr x 1000.
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Could it be because you have less leverage than normal with the shorter cranks, meaning you must exert more force with each revolution (all else being equal)? Are you shifting in a lower gear to compensate?
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Have you double-checked your fit on the bike with 170mm cranks? Knees over the pedal spindle? Has the leg extension angle been checked by a fitter?
Shorter cranks are supposed to reduce the kind of knee pain you're having. Something must be set up incorrectly. Your kind of knee pain generally comes from either saddle too far forward or too low, right? Since shoes, cleats, etc. are the same, most likely one of these two things.
Shorter cranks are supposed to reduce the kind of knee pain you're having. Something must be set up incorrectly. Your kind of knee pain generally comes from either saddle too far forward or too low, right? Since shoes, cleats, etc. are the same, most likely one of these two things.
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This must be what the problem is. I like to stand on the pedals a lot and I do enjoy mashing in a big gear more than spinning.
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I don't necessarily care too much about KOPS. But it's at least a decent starting point. Might be worth a trip to a good fitter before buying new cranks. There could be something you've missed.
FWIW, I'm 5' 10" with a cycling inseam of about 35", and I use 170mm cranks on the primary road bike. And the "backup" road bike has 172.5's. And the mountain bike has 175's. The only time I've had knee problems on any of them was when the fit was off.
FWIW, I'm 5' 10" with a cycling inseam of about 35", and I use 170mm cranks on the primary road bike. And the "backup" road bike has 172.5's. And the mountain bike has 175's. The only time I've had knee problems on any of them was when the fit was off.
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