I have a great tip for old quick release hub bike owners out there. The ones with disc brakes. You probably experience this ervery time you remove the wheels from the dropouts and put them back on. You will see that 9 out of 10 times your disk brakes will rub. This used to make me go crazy and i was readjusting the calipers every time i put the wheels back on. It is especially frustrating when you are out and changing a punctured inner tube. Lately i realized that i didn't even need to touch the calipers. The solution was so simple, just turn the axle within the dropouts (before tightening the QR) to match the previous allignment of the wheel. Give this a try. Quick release axles are not perfectly straight because of the threads on them. So every time you put the wheels back on, the allignment is slightly off (one milimeter maybe), and that much of a difference is enough for the brakes to rub. Like i said, you just need to turn the axle within the dropouts before tightening the qr to find that sweet spot that was when you first removed the wheels off the bike. Just make a quarter turn and try tightening the QR and turn the wheel. If brakes rub, make another quarter turn and try again. Eventually you will find the spot and the brakes won't rub. So much easier than readjusting the brakes.