By Roger Marble
A clarification about the pressure number on a tire might be of help.
The pressure number molded on the sidewall of tires is NOT the “Maximum Allowable” pressure. It is the Cold pressure necessary to support the Maximum Load capacity for that tire. In reality, the pressure number molded on the tire sidewall is the Minimum needed to provide for the support of that load.
Increasing the cold pressure above the number on the tire sidewall will NOT increase the tire rated load capacity per industry practice, standard and guidelines.
If the pressure increases because of increased Ambient Temperature or because the tire gets hot from being in the sunlight, or the tire gets hot from being driven on, that increase is considered and accounted for by tire design engineers. The increase is about 2% for each increase of 10°F in tire temperature. Even a temperature increase of 100°F (20°F to 120°F, for example) would only result in about 20% increase in tire pressure, and undamaged tires can tolerate a greater pressure increase than 20%.
Note: I am not saying that you can heat a tire to above 190°F and not have problems, but those problems would be the result of high temperature degradation of the rubber and not simply due to pressure increase.