Contact patch (footprint) physics is fundamental to the generation of vehicle control forces, tire and road wear, and tire structural mechanics. Footprint physics depends strongly on tire design, pavement topography, and operating conditions. This paper discusses the three-dimensional contact patch stress field of two generic tire types: solid and pneumatic. The discussion is limited to the comparison of the static and free rolling states of both tire types, examination of the effect of the bead-rim boundary condition in the pneumatic tire, and a brief look at the effect of the friction coefficient and viscoelasticity on the solid tire. The discussion is based on experimental results for a smooth-treaded urethane solid tire and a low-pull-force smooth-treaded radial which are assumed to generally represent solid and pneumatic tires. The results obtained offer significant guidance to those who are attempting to mathematically model tires, understand wear, and comprehend the physics of the tire contact patch.