SAE J2784_202101

This document derives from the Federal Motor Vehicle Safety Standards 105 and 135 vehicle test protocols as single-ended inertia-dynamometer test procedures. The test sequences enable brake output measurement, friction material effectiveness, and corner performance in a controlled and repeatable environment. This SAE Recommended Practice (RP) also includes optional sections for parking brake output performance for rear brakes. It applies to brake corners from vehicles covered by the FMVSS 105 and 135 when using the appropriate brake hardware and test parameters. The FMVSS 135 applies to all passenger cars and light trucks up to 3500 kg of GVWR. The FMVSS 105 applies to all passenger cars, multi-purpose vehicles, buses, and trucks above 3500 kg of GVWR. This document does not include testing for school bus applications or vehicles equipped with hydraulic brakes with a GVWR above 4540 kg. This revised document takes into consideration new technologies for braking systems like (a) vacuum assist, (b) electric parking brake (EPB), and (c) regenerative braking. The inertia calculation references the latest version of the SAE J2789 to calculate the test inertia, including two methods to reflect the brake blending for the regenerative system. This revision also addresses formatting and grammatical corrections and clarifies items about FMVSS 105, FMVSS 135, or both. Other aspects of the rationale from previous revisions of this SAE Recommended Practice (RP) are still applicable.