MEASUREMENT OF TRUCK TIRE FOOTPRINT PRESSURES

A triaxial load pin array to measure tire footprint pressures was recently purchased by Texas Transportation Institute (TTI). The triaxial load pin has two important advantages over the pressure-sensing film techniques that have been utilized by other researchers: (a) tire-pavement shear pressures can be measured, and (b) the load pin signal will respond to dynamic tire contact pressure. Preliminary results obtained with the TTI load pin array are described. Footprint pressure distributions were measured for two highway-type radial truck tires and a smooth-tread radial truck tire. The data obtained compared well with footprint pressures measured by pressure-sensitive film at the University of Texas. Comparisons with footprint pressures measured at two major tire companies are also given. Data showing the effects of tire inflation pressure and tire load on footprint pressure developed by conventional and wide-base truck tires are included. The effect of wheel flange offset on conventional truck tire footprint pressure distributions is detected. Recommendations are made for research to systematically investigate other influences, such as tire nonuniformity and the effect of tread wear on truck tire footprint pressures.