I recently bought a Kona Coiler about 4 weeks ago. At first the hayes brakes were excellent and stoped my bike on a dime. In the last few days ive noticed that it takes alot more effort to get the same stopping power from the rear brake. Today it was so bad that the rear wheel would not lock up or stop the wheel even when I slammed the brakes going at a good speed. The wheel would stop but after a few revolutions. I cleaned the rotors and tried a few things but nothing helped. Eventualy I got fed up and switched the front pads into the rear calipers, and now the rear works like when it was brand new. The front brakes now work very bad and hardly stop me, exactly like they did when they were in the rear. My question is that how often do brake pads wear down? could there just be something on the pads that casue them to not grip the rotors? i cleaned the rotors and pads already so i dont think that is the problem. should i just buy new pads and see what happens?