Originally Posted by
Olgaimage
It makes me sad that you want to convince me not to buy them. Other people have also told me that it doesn't matter and I shouldn't do it. But I really want to help my knee. I have been seeing a PT for 6 months and I just had an MRI scan. I only use 2nd, 3rd and 4th gear (not sure if it is the correct way to say it) and I try to avoid hills. I have read an article written by a bike fitter who states that crank arm length is very important and that he and his customers have benefitted a lot from getting shorter crank arms, even just 5 mm shorter. In the article, there is a formula in which you can put your inseam and your "greater trochanter height" and then you get your perfect crank arm length. Mine is 156.6 mm, so 155 mm would be better for me I guess, but I am afraid of buying them so short. I e-mailed the bike fitter and he said that either one of them would be fine for me.
I don't know what a non-profit bike co-op is. It seems impossible to get a 160 mm crank arm in Denmark where I live.
My crank set is FSA.
Someone else in this thread said that my bike probably has an ISO BB because it is the European standard. But my bike or at least some of it is made in Taiwan so maybe it has the other one.
I am sorry that it makes you sad that I am neutral to the idea of your swapping out your crankset. I am happy however that I am not the only one who has advised for the same thing. I guarantee that if you give that 200 Squat program a try that by week 4 you will notice a marked improvement in both knees. Knees are fixed by PT off the bike. FSA bottom brackets are JIS taper. Denmark is a very bike aware country. Maybe you don't need co-ops there but in the United States both what we call LBS's (local bike stores) and bike co-ops (501C3 not for profit corporations) exist side by side to meet the needs of the cycling community. LBS's mainly sell new bicycles from major manufacturers and service the bikes they sell at a discount and other major brands at the earlier stated labor rate. Bike co-ops mainly sell reconditioned bicycles and service all bikes at a reduced labor rate. Sometimes for no charge, often while you wait! If your formula says to get 155mm cranks why are you looking for 160mm? Either you believe that the shorter crank can help or you don't. It does no good to hedge your bets and get a crank not quite short not quite long. "Go big, or go home". In other words, make a change big enough that you can notice whether or not it helps.