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.