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Manufacturers of components for heavy trucks continually seek opportunities to reduce vehicle weight and improve operating efficiency. In recent years, new generation wide-base single (NGWBS) tires, such as the Michelin XOne®, have provided weight reductions from 70 to over 120 kg per axle and improved fuel economy when compared to standard dual tire fitments. The NGWBS tire was designed as a “bolt-on” technology that can be put directly into commercial service on existing vehicles. As an enabling technology, NGWBS tires offer even greater improvements in overall vehicle weight reduction, safety, and fuel economy by permitting adaptation of axle and suspension architecture to take advantage of the single tire geometry and operating characteristics. This paper details the development of a new heavy truck drive axle design which is specifically optimized for use with NGWBS tires.

Radial force variations in tire/wheel assemblies can affect truck ride quality. Radial runout measurements can be a reasonable approximation of the radial force variation, especially for extreme values of either parameter. This study examines the radial runout of over 2,000 tire/wheel assemblies at medium/heavy truck original equipment manufacturers. A method was devised to measure the radial runout of assemblies on the vehicle. The method was validated, and a database generated. This database was then analyzed for statistically significant differences in parameters such as tire (brand, size, or tread), wheel type, wheel piloting, and random vs matched mounting.

This study fills some of the information gap on how heavy truck axle alignment evolves from what is set at the factory to what exists at delivery and after several thousand miles of use. Alignment parameters were caster, camber, toe, and tandem skew. The results give insight to alignment specifications based on measurement capability / repeatability, the evolution of alignment “changes”, and conclusions on desirable alignment practices for OEMs and user fleets.