Experiments using a specially designed device were conducted to determine the performance characteristics of tractor tires under various conditions. Radial ply tires showed superior performance over bias ply tires. Soil had a greater influence on traction capabilities than did tire design. Traction prediction equations for radial ply tires were developed.

The authors are grateful to the University-wide Energy Research Group (UERG), the Armstrong Tire and Rubber Company, The Kelly Springfield Tire Company, and The Goodyear Rubber and Tire Company for their support.