One of the most important parameters to be established for tire operation, whether on a new vehicle being designed by a vehicle manufacturer or on a plus-size fitment, is the recommended cold inflation pressure for the tire. The tire carries a maximum inflation pressure label, but operation at lower loads and pressures is generally beneficial for overall vehicle performance. Recommended inflation pressures have historically been provided by tire standards organizations in the form of tables of load versus pressure or in the form of simple mathematical models. This paper reviews these models along with a recently developed tire-stiffness-based model. Inflation pressure increases over minimum requirements are discussed. One commercial computer program providing tire pressure recommendations along with supplemental labeling for plus-sizing is reviewed.