Low tire pressure error sign. Warning lights flash on the car dashboard.
Keeping your car’s tires properly inflated to the automaker’s recommended pressures is a critical element of tire maintenance. Tires that contain the specified amount of air pressure last longer and contribute to vehicle safety.
Dangers and cost impact
Low tire pressures affect braking distances and provide less responsive steering and handling. This can be especially dangerous when an emergency stop or sudden evasive maneuver is needed to avoid a collision.
In addition, low pressures allow tire sidewalls to flex excessively, which generates heat. While moderate heat simply accelerates tire tread wear, high heat can lead to loss of tread segments or even blowouts.
Underinflated tires also have higher rolling resistance, which reduces fuel economy. They also wear more rapidly at the outer edges of the tread, which means replacement will be necessary sooner than with properly inflated tires.
Overinflated tires are less of an issue. Modern tires can easily withstand pressures that exceed those recommended for normal driving. However, consistently overinflated tires provide a less compliant ride and suffer more rapid wear in the center of the tread, which again means replacement will be necessary sooner than with properly inflated tires.
Determining proper tire pressures
Refer to your vehicle owner’s manual or the tire specification decal on the driver-side doorframe. For older model cars (prior to 2003), tire inflation information may be located inside the glove box door, fuel filler flap, or trunk lid.
Do not use the pressure molded into the tire sidewall. This indicates the pressure needed to meet the tire’s full rated load carrying capacity, not the pressure specified for your particular vehicle.
Vehicle manufacturers provide basic tire pressure specifications that may vary from front to rear, and also when the vehicle is fully loaded or used for extended highway driving. Higher pressures increase load capacity and reduce heat buildup.
Some pickup trucks and sport utility vehicles have light-truck tires marked as “LT” on the sidewalls. The recommended inflation pressure for light-truck tires can vary significantly depending on a vehicle’s load and usage.
Tire inflation tips
- Check tire pressures regularly. Once a week is best, but no less than once a month and always before any long road trip.
- Use a quality pressure gauge. Dial and digital gauges are more accurate and cost $10 to $20.
- Follow the vehicle manufacturer’s recommended inflation pressures and not the pressure molded into the tire sidewall.
- Check the pressures before driving when tires have been at rest and are not hot. An increased pressure reading (typically 2 to 6 psi higher) is normal when tires are hot.
- If recommended by the vehicle manufacturer, increase tire pressures for towing, carrying heavy loads, or extended highway travel.
Additional Tire Maintenance
To equalize tread wear and extend tire life, rotate the tires at the intervals specified by the vehicle manufacturer. If the car pulls to one side, or the tire treads exhibit unusual wear patterns, have the wheel alignment checked and adjusted as necessary.