Development Of New Test Protocols To Study Tire Rolling Resistance Using Simulated Driving Conditions

Surveys have shown that a majority of passenger vehicle tires do not receive proper inflation pressure maintenance. It is estimated that the increased rolling resistance due to underinflated light vehicle tires consumes an excess 700,000,000 gallons of fuel annually in the United States. Previous studies of the relationship between tire inflation pressure and rolling resistance have relied on static testing of the inflation pressure loss rates (IPLR) of tires. In order to study the pressure loss and rolling resistance of tires under conditions that more closely resemble tires when used in service, two new test protocols have been developed.

             Six tires with known ASTM F1112 IPLR (static) and ISO 28580 rolling resistance values were selected in order to develop a dynamic IPLR value obtained during operation on a 1.707-meter roadwheel. After each incremental operation on the smooth drum, the inflation pressure and resulting rolling resistance values of the six tires were measured. An indoor treadwear test was developed in order to study the IPLR and rolling resistance of the tires when operating while the tread was being lost. After each increment of the test on the textured drum, the inflation pressure and rolling resistance of tires were measured along with detailed treadwear measurements, which included laser profiling. A final experiment was undertaken to study the rolling resistance of uniformly-worn tires at specific inflation pressures. These tests allowed the development of a comprehensive model of tire IPLR and rolling resistance under conditions that tires might encounter during normal operation.