This Recommended Practice provides a common method to measure wear of friction materials (brake pad assemblies and brake shoes) and their mating part (brake rotor or brake drum). These wear measurements apply to brakes fitted on passenger cars and light trucks up to 4,540 kg of Gross Vehicle Weight Rating or vehicles category M1 on the European Community.
Brake parts measurement for wear and thickness are common practice on all brake inertia laboratory testing. Whether as a primary objective (as in a wear or durability testing), or as a reference value (as in performance and noise testing), wear measurements are time-consuming and subject to variability when multiple testing methods or techniques are used on the same facility. Most inertia dynamometers test procedures reference a wear measurement, not always ensuring consistency and adequacy. The new braking systems and innovations in brake pads and brake caliper designs, increase the need for more universal and commonized thickness measurements as well as surface features to characterize the braking components. This SAE Recommended Practice is intended as a guide towards standard practice and is subject to change to keep pace with experience and technical advances.