You should check your tire pressure at least once a month, before long trips, and after major temperature changes. The method is simple wait until the tires are cold, press a gauge onto each valve stem, and compare the reading with the recommended PSI on your driver’s door jamb sticker.
It takes about five minutes, and it affects how safely, efficiently, and economically your car runs. Here is when and how to do it, step by step.
Why You Should Check Your Tire Pressure
Tires are held in shape by the air inside them, and that air carries the weight of your vehicle. When the pressure is right, the tire contacts the road the way its designers intended. When it drifts too high or too low, four things suffer:
- Safety. Underinflated tires flex more, build up heat, and are more likely to fail, especially at highway speeds or under heavy loads. They can also take longer to stop.
- Fuel economy. Low tires have more rolling resistance, so your engine works harder and burns more fuel.
- Tire wear. Too little air wears the outer edges of the tread faster, while too much wears the center. Either way, you replace tires sooner.
- Handling. Incorrect pressure can make steering feel sluggish or the ride feel harsh, and it can reduce grip in corners and on wet roads.
The reason regular checks matter is that tires naturally lose air over time, even when nothing is wrong. Air slowly seeps through the rubber, and a tire can lose a pound or two of pressure in a month without any visible sign.
How Often to Check Your Tire Pressure
Check your tire pressure at least once a month. The National Highway Traffic Safety Administration (NHTSA) recommends monthly checks when the tires are cold, and that includes the spare. Beyond the monthly routine, check your tires:
- Before long trips, when extra speed, distance, and luggage put more demand on your tires.
- After major temperature changes. Tire pressure drops by about 1 PSI for every 10°F (roughly 5.5°C) decrease in outside temperature, so a tire that was fine in the afternoon can be low on a cold morning.
- After hitting a pothole or curb, or whenever the car pulls to one side or feels different.
What You Need to Check Your Tire Pressure
You only need three things:
- A tire pressure gauge. Digital gauges are easy to read, dial gauges work well in poor light, and pencil gauges are cheap and compact. Keeping your own gauge in the glove box is more reliable than using a shared one at a gas station.
- An air compressor or gas-station air pump. A portable inflator at home is convenient, but any air pump works. Some stations charge a small fee, so keep a few coins or a card handy.
- Your vehicle’s recommended PSI. PSI stands for pounds per square inch, the standard unit for tire pressure in the United States.
Where to Find the Correct Tire Pressure
The right number comes from your vehicle’s manufacturer, not from the tire. You can find it in two places:
- The sticker on the driver’s door jamb. It lists the recommended pressure for the front and rear tires.
- The owner’s manual. It repeats that information and may add guidance for heavy loads or towing.
That figure is the maximum pressure the tire can safely hold, not the recommended pressure for your vehicle.
How to Check Your Tire Pressure
Follow these steps for an accurate reading:
- Park the car and let the tires cool. Wait at least three hours after driving, or check first thing in the morning.
- Remove the valve cap. Unscrew it from the first tire and keep it somewhere safe, such as your pocket.
- Press the gauge firmly onto the valve stem. Hold it straight until the hissing stops and the reading settles.
- Read the pressure and compare it with the recommended PSI. Note whether the tire is low, high, or right on target.
- Repeat for all four tires and the spare. Many compact spares require a higher pressure than your regular tires, so check the number printed on the spare itself.
How to Check Tire Pressure When Tires Are Hot
Driving heats the air inside your tires, which raises the pressure reading by several PSI. A hot reading therefore looks higher than the true cold pressure.
If you have to check right after a drive, add air only if the reading is well below the recommended level. Then recheck when the tires are cold, and adjust if needed. Do not let air out of hot tires to match the sticker, because the pressure will fall too low once they cool.
How to Inflate Your Tires
If a tire is below the recommended PSI, add air gradually:
- Attach the air hose to the valve stem. Press it on firmly so air flows into the tire.
- Add air in short bursts. A few seconds at a time is enough.
- Recheck the pressure after each burst. Use your own gauge, since the pump’s built-in gauge may be off.
- Stop once you reach the recommended PSI.
- Replace the valve cap. It keeps dirt and moisture out of the valve.
How to Release Air From Your Tires
If a tire is above the recommended PSI, let a little air out:
- Press the small pin inside the valve stem gently. You can use the back of the gauge or a fingernail.
- Release air in short bursts. A brief press lets out only a small amount.
- Recheck frequently. It is easier to let out a bit more than to add back what you lost, so check after every release.
- Replace the valve cap when you reach the recommended PSI.
What Your Tire Pressure Warning Light Means
Most modern vehicles have a tire pressure monitoring system (TPMS). When its warning light comes on, it means one or more tires may be significantly underinflated.
When you see it, use a gauge to check the actual pressure in every tire as soon as it is safe to do so. The light does not tell you which tire is low or by how much, and it usually comes on only after pressure has dropped well below the recommended level. NHTSA describes the system as a warning, not a substitute for manual checks, so keep checking monthly even if the light stays off.
Tire Pressure FAQ
Should You Check Your Tire Pressure Before or After Driving?
Check before driving whenever possible, when the tires are cold. A cold reading is the most accurate, and it is the number the recommended PSI is based on.
What Happens If Your Tire Pressure Is Too Low or Too High?
Low pressure can cause poor handling, faster tire wear, and higher fuel use. High pressure can reduce traction and make the ride harsher. Both shorten tire life, so staying at the recommended PSI is the goal.
Final Tip: Make It a Monthly Habit
Checking your tires is one of the cheapest and most valuable maintenance tasks you can do. To make it stick:
Set a monthly reminder on your phone, such as the first Saturday of every month.
Check all tires, including the spare.
Keep a gauge in your car so you can check whenever the weather turns or a long trip is coming up.
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