what causes rotors to wear unevenly
Dirt or rust between the rotor and hub also can create runout. Cleaning the face of the hub and the inside face of the rotor hat section with a drill-powered circular brush can eliminate this cause of runout. Hard spots in a rotor casting also can cause uneven wear. The hard spots resist wear while the surrounding softer areas experience more wear. It only takes about .001 inches of thickness variation to cause a noticeable pedal vibration.