The Effect of Inflation Pressure on Bias, Bias-Belted and Radial Tire Performance

A great deal of interest is being given to operating passenger tires at significantly higher inflation pressures to reduce rolling resistance. The use of higher inflation pressures, while reducing rolling resistance, will also affect other performance characteristics. The effect of inflation pressure on rolling resistance, tread wear, traction, bruise resistance and mechanical properties of bias, bias-belted and radial tires has been investigated. Inflation pressures from 16 to 48 psi (110 to 330 kPa) were used. At various test conditions radial tire rolling resistance was found to be 12–60% lower compared to the bias and bias-belted tires. The radial tire is less sensitive to load and pressure variations; therefore, its rolling resistance will remain more constant high load and under-inflated conditions. The rate of rolling resistance reduction with increasing pressure diminishes and levels off pressures above 40 psi (275 kPa).

Treadlife increases with higher inflation pressures, but results in a disproportionate center wear condition on both bias and bias-belted constructions. Pressure variations had little or no effect on traction. However, changes in cornering coefficient and aligning torque at higher inflation pressures will require tire/vehicle adjustments to achieve desired handling characteristics.