The Effect of Tire Rolling Radius on Pedal Force Gain and Rollover Propensity of a Light-Duty Truck

A series of low-speed straightline braking tests with two test drivers were conducted on a performance-based brake tester as an exploratory study to examine the effect of tire rolling radius on a light-duty truck. Data collected by the flat plate brake tester and a load cell to measure pedal force were used to evaluate differences in the braking characteristics and rollover propensity of a 1992 four-wheel drive pickup. Tests were conducted with the test vehicle in the stock configuration with standard size tires and after it was equipped with aftermarket body and suspension lift kits and three incrementally larger size sets of radial tires. An analysis of test data indicated that the additional ride height and oversize tires had a profound effect on pedal force gain and significantly increased the rollover propensity of the altered vehicle.