Abstract

Good ride, acceptable comfort for passengers, is a required attribute for all road vehicles particularly automobiles and light trucks. The tire/wheel assembly is a critical component in providing good ride. Indeed, obtaining good ride was the crucial factor that drove the invention of and rapid popularization of the pneumatic tire. Today, the ride effect of tires is often thought of in two ways. The first is in terms of the transmission of vibration produced by the interaction of the tire with road surface irregularities, harshness. The second is in terms of tire structural irregularity generated energy transmitted during operation on a smooth road, uniformity. Both types of energy share the dynamic properties of the tire structure though they differ in source. This paper concentrates primarily on uniformity induced vibration particularly at the frequency of tire rotation, but does touch on harshness to a small degree, when the sharing of structural dynamics makes it appropriate. This review of the subject of force uniformity includes the effect of wheels, as wheels contribute to the vibration that reaches the vehicle spindle. Balance is touched on only as it affects force uniformity in well-balanced assemblies. This is not a treatise on balancing. A suggestion is made, which should, if practical, greatly improve the installed uniformity of tire/wheel assemblies.