For a thread that is a year old this is an interesting one. When I purchased my Burley, I did not check the size of cranks it had. I rode it for a few hundred miles and knew from the beginning that something was not right. I was ready to change the stem, the seat post to a zero set back, new bars, anything I could think of that would make the fit feel right. Then one day I measured the cranks and they were 175. All my other bikes have 170 cranks. I swapped the cranks and there it was. Spinning again and no knee problems.