The elastohydrodynamic (EHD) traction coefficients of a lubricating grease LGLT2 were tested at various loads and rolling speeds on a self-made test rig. Traction coefficient versus slide-to-roll ratio curves were generated. Formulae which relate traction coefficient with normal load and rolling speed are put forth. The coefficients of the formulae may be computed by regression analysis of the experimental data. The results show that the calculated traction coefficients agree well with the experimental observation. The critical normal load exists when the traction coefficients change with the normal loads.