Originally Posted by
Road Fan
Bill, I've recently noticed my knees feeling tired after a ride and on my stairway the day after. I've been using 172.5's on two bikes this year, and finally noticing it's hard to keep up a good spin. I have more force at lower cadences, but find it harder to maintain 85-90 like I was doing last year with 170s. My pedaling keeps dropping down to the 70-75 range. I think you hit on something, thanks!!
I think I'm going to change back to 170 on at least one of them and see what happens regarding cadence and knee pain. I do know last year I rarely had knee discomfort after long rides.
Road Fan
It could be that "Father Time" as resulted in a slight loss of flexibility in your knee.
It's nice to have a different length arm available to try out to see IF it makes a difference.
Post back about any difference you did or didn't experience.
At least you have a good, established reference point to compare to.
I still find it a bit odd, never using the big ring anymore, while before that, was all I used.