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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.

An optical method based on white light refraction and reflection is described for the measurement of normal contact stress between “soft” structures and a rigid transparent surface. The objective is to provide information on the background of the method used and on the practical aspects of the application of the method to the experimental tire analysis. The method used allows visualization of tire contact patch geometry as well as of the normal stress distribution in the contact. Experimental setup, calibration, data collection, and data analyses are presented. Footprint contact analysis of static and rolling tires are illustrated on several examples.

Indoor or laboratory testing of tire tread wear offers many advantages over vehicle fleet testing. Advances in test equipment capabilities and the technologies for defining and simulating meaningful tire loading histories has made indoor tread wear testing a reality. Tire loading histories are influenced by vehicle characteristics, wear course and driving style, and tire stiffnesses. Methods for independently characterizing each of these are reviewed. A simulation technique, TS-Sim, is also described that combines specific vehicle, course and tire characterizations to create a tire load history. The vehicle characterization is critical to the process since both wear rate and various forms of uneven and irregular wear are strongly dependent on vehicle suspension/steering characteristics and on dynamic load transfer behavior. The characterization process involves mapping the vehicle over a practical range of acceleration, deceleration and cornering maneuvers.