Why Must the Temperature-Viscosity Dependence be Altered to Apply Eyring to EHL friction?

High-pressure viscometry has been beyond the capability of most tribologists, although some of the techniques have existed for a century. As a substitute, tribologists have attempted to employ elastohydrodynamic contacts as viscometers. Here, for perhaps the first time, concentrated contact full-film friction has been successfully used to establish the shear dependence of viscosity for shear stress extending beyond the available viscometry. The necessity of unrealistically altering the temperature dependence of viscosity to use the sinh-law in a traction calculation is explained.