J2986_201901 Brake Pads, Lining, Disc, and Drum Wear Measurements

Measuring mass and thickness loss of friction materials (brake pad assemblies and brake-lined shoes) and their mating parts (brake discs or brake drums) is a common practice during most inertia dynamometer and vehicle tests. Mass and thickness loss are some of the main criteria to assess the performance and behavior of the wearable brake components. This makes repeatable and reproducible wear measurements a must. This Recommended Practice presents the default measurement methods for the parts in the friction couple. SAE J2986 can be considered as a companion document to supplement laboratory or vehicle test and measurement programs.

The measurement methods presented in this Recommended Practice are useful to determine and report the mass and thickness properties (initial, intermediate, and final) of the friction couple or individual components. These measurements apply to brake parts preparation for mechanical testing, or other testing inducing wear or dimensional changes on the friction materials or their mating components.