SAE J2115_200608

This SAE Standard provides test procedures for air and air-over-hydraulic disc or drum brakes used for on-highway commercial vehicles over 4536 kg (10 000 lb) of GVWR. This recommended practice includes the pass/fail criteria of Standard No. 121. This revision of the SAE J2115 includes several enhancements and fine-tuning relative to the previous version. The main objectives for the revision were to bring it closer to the FMVSS 121 dynamometer test, focus on air brake systems, and to update the wear sections to reflect current industry practices for durability testing. This revision limits the scope to air-braked vehicle applications only. There are provisions for disc and drum brakes. The test conditions include parameters and response characteristics for the servo controller on the inertia-dynamometer. The test setup provides an alternate method for measuring drum or disc bulk temperature using a 9-thermocouple array. Wear sections reflect better current industry practice for assessing wear characteristics versus temperature. The wear sections include intermediate effectiveness evaluation at the corresponding temperature step as well as a baseline temperature of 100 °C. These effectiveness sections help assess any changes or trends on brake output as an effect of the material wear and the temperature history during previous sections. Temperature steps are better harmonized with International Standards for disc brakes. Lastly, Appendix A indicates the FMVSS 121 performance requirements during the different test sections for air brake systems used on different tractors, trailers or other commercial vehicle applications.