Hunter Automotive
3 minutes
Brake Rotor Thickness Measurement
Rotor thickness is measured with a micrometer at multiple points around the friction surface and compared to the minimum ('discard') thickness cast into the rotor hat — for a Gen 4 Prius, 25.0 mm new and 22.0 mm minimum front per the Toyota repair manual. Below minimum, or with variation between points, the rotor cannot store or shed heat safely and must be replaced, not machined thinner.