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Use of passenger and light truck vehicle fleets is likely to increase. Reducing operating cost is a common objective of fleet owners. Tires impact cost in two primary ways, rolling resistance and replacement cost. The total cost due to rolling resistance, replacement cost, and other secondary contributions is referred to as ‘tire total cost of ownership’. Both costs due to rolling resistance and replacement are a function of the driving route and the tread depth. In this paper, tire total cost of ownership for a broad distribution of routes is compared in a relative sense to the other route-dependent energy consumption costs resulting from vehicle inertia and vehicle aerodynamic drag. The algorithm developed includes the route history of velocity and forces on the tires and their effect on tire rolling resistance, tire wear rate, energy required to accelerate the vehicle inertia, and the energy lost to aerodynamic drag.

The ease or difficulty of mounting a tire on a rim depends on many factors which can be quantified by the torque that must be applied by a tire mounting machine on the tire. It was determined that the in plane and out of plane stiffnesses of an un-mounted tire have significant influence on this mounting torque. In addition, it was observed that a lateral deformation applied on the tire sidewall and the bead can also influence the mounting torque and this effect depends on the un-mounted tire stiffnesses. These observations can be explained based on the mechanics of the tire mounting process. Case studies will be presented to illustrate the influence of tire stiffness and deformations on mounting difficulty. Tests that were developed to measure the tire stiffnesses and mounting torque will also be discussed.

Tires flatspot when they remain loaded without rolling for a period of time. When the tires are rolled again, the initial flatspot decays and vanishes or stabilizes to a much smaller magnitude (called residual flatspot). Flatspot is a low harmonic phenomenon and primarily contributes to the first three or four harmonics of tire run out. The tire non uniformity caused by a flatspot may induce noticeable vibrations in some vehicles during operation in the decay process. The magnitude and decay of a flatspot depends on many factors - tire construction, material creep properties, tire radial load and time duration, inflation, tire and ambient temperatures, tire mileage, etc. In this paper, the fundamental concepts involved in the formation and decay of flatspot are discussed. These characteristics can be objectively measured in a laboratory and flatspot trends can be explained.