At exactly 64-68 mph, I get a clack-clack-clack sound from the right rear of bike. Approx. 120 times per minute. Can't find anything loose, speed specific, don't have anyone to ride next to me. It only does it at these speeds. Any ideas? New me880's w/2k on them, no bumps noticible on rear tire. I'm stumped!!!
Thanks, Dan