A complete steady-state thermal analysis was made for a rolling passenger tire. A numerical network analysis was used which involved the solution of a set of simultaneous heat balance equations. Conduction within the tire, conduction to the road surface, convection to the contained air and to the surrounding air, and radiation from the outside and inside surfaces of the tire were taken into account. The experimentally measured infrared surface temperature distribution was used as input data. The results gave the complete distribution of temperatures and rates of heat generation in the tire. The calculated power loss and shoulder temperature of the tire agreed well with experimental results obtained on an indoor road wheel. Radial and bias ply rayon tires of equivalent size were compared. The radial tire ran cooler and had lower power loss.