Proper Tire Pressure for Cars
What Is Tire Pressure?
- Tire pressure is the measure of the inflation within a tire and is most often measured in pounds per square inch, or PSI. Tires require a specific amount of internal air volume to operate efficiently, providing the durability, traction, and performance required by the vehicle it is designed to fit on. Automobile manufacturers determine the tire pressure required for a given vehicle by evaluating the vehicle weight, the purpose and the physical dimensions of the tire, adjusting for additional load capacity, such as passengers, as needed.
Finding the Proper Tire Pressure
- All vehicles produced since 1968 are required to list the original specification tire sizes and cold inflation pressures for all tires used on the car. This information is located in the vehicle's owners manual, as well as placards located on the vehicle itself. This placard is normally found on the driver-side door or door jamb. Alternatively, the manufacturer may place this placard in the glove box, fuel filler door, or engine compartment.
Advantages of Proper Inflation
- Maintaining a proper tire pressure can serve several advantages. First, the tire itself is better stabilized against the sidewall flexing as the tread connects with the road, preventing a loss of traction and premature tire failure. Heat buildup and rolling resistance is also reduced, the latter of which contributes to increased fuel efficiency as the car strains less against its own wheels.
Setting your Tire Pressure
- It is recommended to check and adjust your tire pressure in the morning, before setting off. Set your tire pressure while your tires are still cold, using the manufacturers recommended tire pressure found in your owners manual or on your vehicle's placard. Adjustments should be made at this time, depending driving conditions or the duration of your trip. If you park your car in an enclosed garage during winter, for example, you should inflate your tires an extra 1 psi for every 10 degree difference in outdoor/indoor temperatures. Also, long trips with sustained speeds over 45mph should have a 6 psi increase over the recommended rate.
Disadvantages of Improper Inflation
- Tires can suffer terribly if improperly inflated. Over-inflation stresses the sidewalls and structure of the tire, leading to the possibility of blowouts occurring as internal heat builds up, causing the air within to expand. Over-inflation will also override the tires ability to absorb road surface irregularities, transmitting every bump directly to the interior of the vehicle. Under-inflation, on the other hand, prevents the tire from maintaining its shape, weakening its internal structure and generating an increase in rolling resistance. Tread life is also decreased as much as 25 percent.
of a passenger car tire's recommended pressure.