Given that it is soooo easy to diagnose noises on the forum, uh, I have this rythemic thump coming from somewhere in the rear drive line. I will pull the wheel this weekend and further investigate. My question is, does a single rear wheel rotation, equal a single chain rotation? I can figure this out if I want, but it seems simplier to ask. That will help me narrow it down to dry link in the chain, bad tire, bearing failing, or some other stupid thing. Any guess appreciated. Will post if there is a nail head sticking out of the tire!