i have been having troubles with my trek rear rack rattling loose, so i tightened the crap out of the bolts, one head broke off, and one I stripped the threads on the bolt and messed up the threads on the frame, so i tried to drill and tap it and the whole nut assembly spun in the frame(w/ the tap stuck in it) so i pulled it off with pliers(ruined ever having a chance of attaching anything there) so i made an adapter and just attached the rack to the brake caliper bolt hole, oh yea i used lots of locktite this time!the rack shouldnt ever rattle loose again. im so glad i got it back on, i was afraid i was going to have to get a new frame, just b/c of one little stripped out nut