How to Check Tire Pressure
Checking tire pressure is a quick task that improves safety, tire life, and vehicle performance. The key is using the manufacturer’s recommended pressure, measuring tires when they are cold, and investigating any tire that repeatedly loses air.
Find the Correct Pressure
The best source is the tire-pressure placard, usually on the driver’s door jamb or inside the fuel door. It may list separate pressures for the front and rear axles. Some vehicles also provide a pressure for the spare tire. If the placard is missing, consult the owner’s manual.
- Use the pressure specified for your vehicle, axle, and normal load.
- Do not use the maximum pressure printed on the tire sidewall as your target. It indicates a safety limit, not the normal operating pressure.
- Never inflate a tire beyond its sidewall limit. If the placard and sidewall disagree, contact the vehicle manufacturer or a qualified tire professional.
Check the Tires When They Are Cold
Cold pressure gives the most accurate comparison with the placard. For many vehicles, this means the car has been parked for at least about three hours or driven no more than about one mile at a moderate speed. If the vehicle has been driven recently, wait until the tires cool before making a final adjustment.
- Park on level ground and set the parking brake.
- Check all road tires, including the rear tires, even if the vehicle appears to handle normally.
- Check the spare if it is part of the vehicle’s tire system.
Warm tires generally read higher than cold tires. Do not release air from a warm tire simply to match a cold-pressure figure.
Measure and Adjust the Pressure
- Remove the valve cap. Keep it somewhere safe so it does not disappear into the tire well.
- Connect the gauge. Press firmly against the valve stem until the hose or gauge is secure.
- Read the gauge. The displayed value is the tire’s current pressure. Digital gauges are usually easier to read, while a checked mechanical gauge can also be accurate.
- Compare the reading with the recommended pressure on the placard.
- Add air if needed. Use short bursts, then check again. This helps prevent overinflation and allows the gauge to register the pressure correctly.
- Let excess air escape if a tire is overinflated. Recheck it before replacing the valve cap.
After using the gauge, press the valve stem to confirm that it is operating correctly and listen for a faint hiss. If air escapes steadily, or the gauge loses pressure while connected, the valve may need service.
After Changing a Tire
Recheck cold pressure after mounting a tire, especially if the wheel was previously underinflated. A tire may not reach its intended pressure while installed if the bead is not seated correctly, so verify the reading after the vehicle has stood still.
- Inspect the tire for cuts, bulges, exposed cords, or objects embedded in the tread.
- Confirm that wheel nuts are tightened to the manufacturer’s specification.
- Make sure the valve cap is secure and the tire is not rubbing against the wheel or suspension.
Recognize Warning Signs
Underinflation can increase heat buildup, rolling resistance, and irregular wear. Overinflation can reduce the contact patch, create a harsher ride, and make the tire more vulnerable to damage. Both conditions can affect braking and handling.
- If one tire repeatedly loses pressure, inspect it closely and have it checked for a puncture, valve leak, or wheel damage.
- If readings differ substantially across tires on the same axle, have the suspension, wheel, and tire setup checked.
- Do not rely solely on the tire-pressure monitoring system. Use a gauge regularly, especially before trips, and treat a persistent warning light as a reason to inspect the tires.
Make Tire Checks a Routine
Check pressure monthly and before long journeys, but also inspect tires whenever you notice unusual wear, a pulling sensation, or a warning light. Keeping a record of each reading can reveal gradual air loss or inconsistent inflation before a problem becomes serious.