The Importance of Proper Tire Pressure

Checking your tire pressure and airing up your tires is one of the most important pieces of car maintenance you can do. Luckily, it is also one of the easiest. Air can be found at most gas stations, and they likely have everything you need right there. Even if you prefer to have a tire shop in Northwest Indiana handle all your tire maintenance, it's important to understand how much the pressure of those tires affect the performance of your vehicle. Both over inflation and under inflation have negative effects. Just consider what happens when your tire pressure is off:

  • It decreases gas mileage up to 3%.
  • It causes uneven tread wear, which decreases the life of the tire (see diagram below).
  • It is the number one reason for blowouts. Car accidents resulting from blowouts cause thousands of injuries and hundreds of deaths every year.
  • It decreases the driver’s ability to properly handle the vehicle.
  • It is a very common problem. At any given time, over one-third of American vehicles have at least one underinflated or overinflated tire.

Here is a look at how improper pressure or damaged suspension parts effects tire tread.

Tires in Disrepair

Tire Pressure Changes

Tire pressure is constantly changing. Tires typically lose about one PSI (pounds per square inch) every 30 days.  For every 10 degree change in temperature, tire pressure will change 1 to 2 PSI.  Warm weather typically causes an increase in tire pressure while cold weather will cause a decrease in pressure.  Tires can lose pressure by hitting a curb or pothole.  If valve caps are missing, it can cause a slow leak in pressure.

Know Your Recommended PSI

The proper tire pressure for a vehicle is listed in the owner’s manual and on the driver’s door jamb. Do not use the number listed on the tire sidewall. This number indicates the maximum pressure that tire can hold.  Small or mid-sized sedans will typically have a recommend PSI of 30 to 40, while larger sedans or light trucks will have a recommended PSI of 40 to 50.

Checking Your Tire Pressure

Keep these simple things in mind when checking and adjusting your tire pressure:

  • Check tire pressure on a monthly basis, and more often with major temperature changes.
  • Be sure to use a reliable pressure gauge. Keep one handy in your glove compartment.
  • Check the pressure in your spare tire as well. You never know when you may need it.
  • For the most accurate reading, check tire pressure when the vehicle has not been driven for a few hours. Driving causes tires to heat up, which can affect tire pressure readings.
  • Replace any missing valve caps to prevent air leakage.
  • Tire pressure should be the same for tires on the same axle, but may be different between the front and rear axles.
  • Do not allow your tires to go 5 PSI over or under the recommended level.