This SAE Recommended Practice provides the test procedure and methods to calculate the effectiveness of brake blocks, using an inertia dynamometer. To minimize testing variability, and to potimize standardization and correlation, a single, high volume size of brake block is specified (FMSI No. 4515E) and evaluated in a reference S-cam brake assembly of 419 mm x 178 mm (16.5 in x 7.0 in) size, using a specified brake drum. The purpose of this document is to establish a uniform procedure for the determination and classification of brake effectiveness for commercial vehicle brake blocks. This document will permit comparison of basic frictional properties for brake blocks. Service usage classification ratings and applicable axle load ratings are not included in this document.