How to Check Your Tire Pressure (and Fill It)

Tires lose air slowly, even when nothing's wrong. The government's tire safety site says to check them at least once a month. It takes five minutes and a cheap gauge. Here's how.

1. Step 1: Find Your Number

First, find the right pressure for your car. Open the driver's door and look for a sticker on the door frame. It lists the pressure for the front and rear tires, in P S I. It's in your owner's manual too.

2. Not The Sidewall

Don't use the number printed on the tire itself. That's the maximum the tire can ever hold, not the pressure your car needs.

3. Step 2: Check Them Cold

Check the tires when they're cold, before you drive, or after the car has sat for about three hours. Driving warms the air inside, and makes the reading higher.

4. Step 3: Read The Gauge

Unscrew the little cap on the valve stem. Press the gauge straight onto the valve, firmly, so you don't hear air hissing out. Read the number, and compare it to the sticker.

5. Step 4: Add Air If It'S Low

If it's low, add air in short bursts, then check again. If you go over, press the little pin in the center of the valve to let some out. When it matches the sticker, screw the cap back on.

6. Do All Four, Plus The Spare

Do all four tires, and check the spare too, if your car has one. Even with a tire pressure warning light, a monthly check with a gauge is still a good idea.