Originally Posted by Alox

Therefore the for the BR505, the distance between the fixed pad and the rotor has to be very small (less than 1mm) to make braking efficient, and this can drive you crazy trying to balance the closeness fo the pad while preventing the rotor from dragging on the stationary pad. This also makes it very hard to set up the calipers on the BR505's properly, since you can't just loosen the bolts and center the caliper - you have to position the stationary pad, then figure out how to position the moveable one - with the brake cable pre-tensioned - and adjusting the rotor gap to accomodate the travel in the brake lever. .