One of a tyre’s primary tasks is to carry the weight of the vehicle. But anyone who’s ever had a flat tire knows that the tire doesn’t really carry the load…the inflation pressure inside it does! Using the correct inflation pressure not only provides the appropriate load capacity, it also enhances the tire’s performance, durability and contribution to vehicle fuel economy.
Tyres are typically inflated with air that’s a combination of roughly 78% nitrogen (N2), 21% oxygen (O2) and 1% miscellaneous gases. And since all gasses expand when heated and contract when cooled, tire inflation pressures rise and fall with changes in temperature by about one psi (pound per square inch) for every 10° Fahrenheit change in temperature. This is one of the reasons it’s recommended that tire pressures be checked early in the morning before ambient temperatures, the sun’s radiant heat, or the heat generated by driving causes the tire pressure to rise.