The maximum load and maximum inflation pressure are required to be branded on the sidewall of tires sold in North America.
Tire pressures are normally measured in "pounds per square inch" (psi), Kilopascals (kPa), or bars of pressure (bars). At sea level, Earth's atmosphere is pressing against the surface with a force of 1 kilogram per square centimeter. This pressure is identified as one "bar," and is equal to 100 Kilopascals or 14.7 pounds per square inch of pressure.
Note: 1 psi = 6.895 kPa
A 225/50R16 92V-sized tire as used in our example would have its maximum load and maximum tire inflation pressure typically presented on the sidewall as follows:
North American Codes Only
Max. Load 630 kg (1389 Lbs)
Max. Pressure 300 kPa (44 Psi)
This branding identifies that tires in the 225/50R16 92V size used in this example must be capable of, and be rated to carry 630 kg (1,389 pounds). Additionally it identifies that the maximum tire inflation pressure for this tire is 300 kPa (44 psi).
It is important to note that the maximum load is rated at an industry specified tire inflation pressure that is often lower then the tire's absolute maximum tire pressure. The tire pressures used to determine the maximum load the tire is rated to carry is based on the sizing system industry standards applied to the tire.
|Sizing System||Tire Load Range||Load Pressure|
Reinforced or Extra Load
However, the tire's maximum inflation pressure may be greater, such as 300 kPa (44 psi) in this example or even 350 kPa (51 psi). This is done to accommodate the vehicle manufacturer's desire to tune the tires' high-speed capability, handling qualities and/or rolling resistance to better suit the vehicle.
It is important that owners consult their vehicle's tire information placard (usually found on the driver's door or doorjamb) or their owner's manual for the recommended tire pressures for their vehicle's driving conditions.