i'm just about fed up with my rear wheel pulling out of my old trek's rear horizontal dropouts at the most embarrassing times. (ie. blasting away from a light or up a steep incline.) up to this point i haven't had too much trouble, but lately i've busted a couple of bolt on QR's when attempting to tighten them so as to actually be effective in keeping my rear wheel on. so i'm thinking about getting a hollow threaded rear axle