INTRODUCTION IN JANUARY, 1972, the International Society for Terrain-Vehicle Systems, Inc., and the Society of Automotive Engineers, Inc., published a paper entitled Load Support Capability of Flat Plates of Various Shapes in Soils, by Dr. I. R. Ehrlich and Colonel A. D. Sela [1]. In this work, Dr. Ehrlich and Colonel Sela presented a significant improvement upon the long used methods of M. G. Bekker for predicting the loadbearing capacity of flat plates sinking into soft soils. In a subsequent paper, Prediction of Rigid Wheel Performance from Plate Sinkage Tests [2], prepared for the Department of Defense under Project Themis, Dr. Ehrlich and Colonel Sela carried their work one step further and developed equations for predicting the performance of rigid wheels in soft soils under no slip conditions. In this paper, experimental validation was performed in sand by Captain F. G. Smith [3]. It was the objective of this research project to provide further experimental validation for Ehrlich and Sela's wheel performance prediction equations in a clay soil. A secondary objective was to provide additional support for the use of the system constant as a means of comparing wheel performance.