I had a good mechanic comment that my chain was too tight this weekend. I adjust it for 1" of slack, and the chain can move up and down 1". He says that it should be LOOSE for 1", not just movable for 1". I thought I knew what I was doing, but now I'm confused. If I run it looser it rattles. If I understand the CRF right, the tightest point for the chain is with the rear wheel fully extended on the stand. If that is correct, then I can't see what I'm hurting.