PROPER INFLATION PRESSURES

One of the most important yet simple services to improve your tire performance is to properly inflate tires to suit your needs. Inflation pressure affects the tread profile shape and the contact pressure across the tread surface. Changing the inflation pressure alters how the tire will function on your customer's vehicle.

The pressure should never be below the minimum listed on the vehicle placard nor above the maximum branded on the sidewall of a specific tire in normal driving conditions.

The best recommendation is to use the inflation pressure specified on the vehicle placard. The O.E. vehicle manufacturer has determined this pressure is optimal for load, ride handling, rolling resistance and treadwear performance.

Higher inflation pressure increases the crown radius of the tire, reducing the contact pressure at the shoulder and giving a slightly smaller footprint.

In general, performance improvements of higher inflation pressure include steering response, fuel economy, hydroplaning resistance and treadwear (less shoulder wear).

Lower inflation pressure decreases (flattens) the crown radius of the tire, increasing the contact pressure at the shoulder. In general, performance improvements of lower inflation pressure include smoother ride, snow traction, bruise resistance and less strain to suspension system components.

For the everyday driver, it is imperative to make sure the tire pressure is adequate to support the vehicle load. The vehicle's placard will indicate the proper inflation pressures/load index.

Make sure to check the tire's sidewall or the vehicle placard for the specified inflation pressures for the tires. Never exceed the maximum inflation pressure branded on the sidewall of the tire.

A rule of thumb to remember is all passenger and light truck tires, for highway use, should never be inflated less than 20 psi. For any 16.5" rim diameter light truck tires, the minimum inflation pressure is 30 psi. Pressure lower than those specified can only be used off-road, when speeds are lower than 15 mph. However, ensure the load-carrying capacity is still adequate to avoid tire failure. When the tires are returned to highway use, they must be re-inflated to at least the minimum specified inflation pressures to avoid handling impairment.