Tires, Pressures and Pavements

All vehicle inputs to pavement are transmitted through tires. An understanding of pavement damage, therefore, requires an understanding of the role of the tire. This paper presents basic tire mechanics and discusses tire to pavement contact stresses. Determining the pavement damage potential of various tire/load/pressure combinations is of particular interest to pavement designers. In the past, attention has been focused on the load and pressure of particular tires without regard to their utilization. Herein is presented a new concept which incorporates the frequency of use of tires of interest since pavement damage is cumulative and results from multiple passes. It is logical then to focus attention on the most widely used highway tires, many of which are running overinflated. Specialty tires do not generate as many pavement cycles and, therefore, may not be detrimental to pavements even though they may require higher inflation pressures. Thus, proper tire pressure selection of widely used tires could tend to benefit pavements. Air pressure selection is explained with emphasis on matching pressure to the maximum service load. The advantages of proper tire inflation to the fleet are also discussed.