Drum and Disc Brake Static Performance Test Equivalency
J3192
This SAE Recommended Practice is intended for measuring the static brake torque performance of a pnuematically actuated brake assembly, friction material, and drum/disc combination on an inertia brake dynamometer.
This document establishes a laboratory test procedure for determining the static breakaway torque of a specified brake model, brake lining, and brake drum or disc. The intent is to be able to compare the static breakaway torque performance of this specific combination and the draw-bar test data from an FMVSS121 vehicle test using the same friction material and brake drum or disc combination to another dynamometer test using the same friction material, but a different brake drum or disc. A test result meeting dynamometer FMVSS121 requirements, along with demonstrated equivalency of the dynamometer static breakaway torque for the same friction material but with different drums or discs, will enable the drums or discs to be considered interchangeable.
Rationale: This document was developed because of the need of trailer manufacturers to verify parking brake performance in accordance with FMVSS 121 / CMVSS 121 when sourcing brake drums or discs.