SAE J 257

The performance values in this SAE Recommended Practice are applicable to vehicles with brake systems having typical service pressure ranges 0 to 14.1 MPa (0 to 2050 psi) hydraulic or 0 to 830 kPa (0 to 120 psi) air only. SAE J880 not only provides for determining maximum brake rating horsepower capability, also permits verification of any desired or arbitrary level such as the requirement established herein. The determining criteria for deciding brake rating horsepower capability are: a. cold brake stopping ability; b. fade as a result of horsepower absorption; c. hot brake stopping ability following horsepower absorption; d. brake system stability following horsepower absorption; and e. functional and structural integrity of brake system following test.

The purpose of this document is to establish a minimum Brake Rating Power (BRP) level for commercial vehicles tested in accordance with SAE J880.