The SAE Recommended Practice establishes minimum performance requirements and related uniform laboratory test procedures for evaluating lateral (curb) impact collision resistance of all wheels intended for use on passenger cars and light trucks.
A process of compensating for frictional losses is recommended to minimize test variation between machines and assure the anticipated velocity is met. The machine calibrator will determine the Adjusted Drop Height (ADH) that the respective machine must drop from to replicate 230 mm of free fall. Certifying the spring rate of the four rubber mounts is difficult in the apparatus as originally shown in the document. An alternate method to certify the spring rate is provided using common load vs deflection machines. One can certify rubber mounts four at a time. Test pressures for temporary ‘T’ and light truck ‘LT’ applications are provided since they operate at pressures substantially different than passenger ‘P’ tires. The intent is to test the wheel at the lower end of the pressure specified for the application. The document title is changed to include “Lateral Impact” to distinguish it from the road hazard impact test that uses an impact in a radial direction per SAE J1981. Reports for the lateral impact test and calibration are in the appendix to ensure uniform reporting. Refer to Appendix A. An alternate construction allowing for constraining the rubber mount and rotating the wheel while on the machine is provided. Background of Lateral Impact Test Procedure – Road Vehicles is provided. Refer to Appendix C.