Air Pressure

Are your tires set at the optimum inflation? Chances are they are anywhere from 8psi to 18psi less than recommended. The most common way of damaging tires is improper inflation. Low air pressure causes tires to experience irregular treadwear as well as poor vehicle handling and traction. Under inflated tires can build up excessive heat and blow out without warning.

Keeping your tires set at the manufacturer's recommended pressure is one of the easiest ways of saving gasoline, increasing tire treadlife, and ensuring safety. An Arizona Energy Office Report notes if your tires are inflated to 24psi, and you increase the air pressure to 32psi, your fuel mileage should increase by 3 miles per gallon (an average increase of 10%!)

Always check your air pressure and make adjustments when the tires are cold (tires have not been driven for 2 hours). Air pressure should be checked bi-weekly at the very least. This is important because as outside temperatures change, so does tire air pressure. A 10 degree drop in temperature can reduce tire pressure by 1psi. That means if you set your pressures in the July and don't check them again until December, you could have lost several psi, decreasing fuel mileage and causing pre-mature tire wear. Also remember to check your spare tire for loss of air.

If you are unsure how to use an air pressure gauge and hose, your local tire shop should be willing to show you the correct procedure. Always use a good quality tire pressure gauge that is not on a hose. The tire gauges built into the air hoses at your local garage have generally not been maintained and can not be trusted to be accurate.

*Note, air pressures can be “tuned”, however you should NEVER exceed the maximum pressure branded on the tire’s sidewall, and NEVER set pressures lower than recommended in the vehicle’s owners manual. Also, if you have altered your tire size from original, then the minimum pressure may need to be adjusted. Consult a rim/tire professional for correct pressures.

Tire Pressure Monitoring System (TPMS)

There are two types of TPMS technologies available in the market: Direct and Indirect.

TPMS symbol


Direct TPMS type involves the use of pressure sensors attached to each tire and wheel assembly which measure the tire pressure and transmit the data through low frequency signals to the vehicle’s computer system. This information is displayed on the vehicle’s instrument cluster usually in the form of a simple pictogram (low pressure warning light) or readings for each tire. There are two types of direct TPMS sensors – Banded sensors and Valve Sensors. Banded sensors attach to the barrel of the rim by a metallic strap.

Valve sensors attach to the rim just like a regular valve stem would, either rubber or aluminum.


Indirect TPMS uses the vehicle’s Antilock Breaking System (ABS) to monitor the diameter of each tire through wheels’ rotational speeds. The under-inflated tire is determined because of a higher angular velocity of its slightly smaller diameter.