Test Procedures for Future Tire Noise Regulations

Based on the actions of the U.S. Environmental Protection Agency and the State of California, it appears that Federal and/or state regulations on tire noise are imminent. Basic questions involving the measurement procedure and other technical problems are likely to arise in the development of such tire noise regulations. This paper treads two specific questions, the first dealing with the load/tire inflation pressure adjustments recommended in SAE J57a and the second with the effect of tire size on tire noise. Based on the limited set of data presented, it appears that either the load/tire inflation pressure recommendations of SAE J57a or the more convenient alternative of maintaining the tire inflation pressure constant at the maximum rated value with reduced loading can be used provided the loads are greater than 70- 75% of the maximum rated tire load. It also appears that compliance testing using a single tire size is feasible since sound level variations with size for tires with similar carcass construction and tread design are small.