Brake Rotor Thickness Variation Measurement
Check thickness variation by measuring the rotor thickness at four or more points around the circumference of the rotor. Use a micrometer calibrated in centimeters (ten-thousandths of an inch). Make all measurements at the same distance in from the edge of the rotor.Important: When refinishing brake rotors the maximum thickness variation should be no greater than 0.013 mm (0.0005 inch).
A rotor that varies in thickness by more than 0.25 mm (0.001 inch) can cause pedal pulsation and/or front end vibration during brake applications. A rotor that does not meet these specifications should be refinished to specifications or replaced.