Originally Posted by BinkyTurtle

My LBS says an elliptical crank is bad for me, but most of what I read on the web says the Shimano Biopace, because the crank is alligned opposite from most ellipticals, did not cause knee injuries. It is just that it may not have been all that it was cracked up to be in the performance dept. As I said, high performance is not an issue, given my injury. I just want to keep active and avoid further injury. It seems like if the bike was going to injure me it would have in 19 years. I want to change the left shifter, which is not original, and does not perform well, but they are telling me they need to replace the whole drive chain. Any ideas from you pros?