Mainting proper tire pressure is one of the easiest yet most overlooked aspects of car maintenance. Driving on under-inflated tires can significantly lower your fuel economy, reduce handling capabilities, and even lead to a dangerous blowout on the highway. Conversely, over-inflated tires can lead to uneven wear and a harsh ride.
Fortunately, checking your tire pressure is a skill that takes less than five minutes to master and requires zero mechanical background. You don’t need to wait for a full service or awkwardly ask a stranger at the gas station for assistance. By following a few simple steps, you can ensure your vehicle is safe and road-ready entirely on your own.
Locate the Correct Pressure and Get a Gauge
Before you touch the tires, you need to know what the “correct” pressure actually is. A common mistake is looking at the number molded onto the tire’s sidewall; however, this is the maximum pressure the tire can hold, not the recommended pressure for your specific car. Instead, look for a sticker located on the driver’s side door jamb (where the door latches when it closes). If it’s not there, check your owner’s manual or the inside of the fuel filler door. This number is usually measured in PSI (pounds per square inch).
Next, you need a tire pressure gauge. These are inexpensive tools available at any auto parts store or gas station convenience store. You can choose between a standard pencil gauge (which pops out a little stick with numbers) or a digital gauge (which gives you an exact screen reading). Keep this tool in your glove box so you never have to scramble to find it when a dashboard warning light pops up.
The “Cold Tire” Rule
Timing is everything when it comes to accuracy. As you drive, the friction between your tires and the road generates heat, which causes the air inside the tires to expand. If you check your pressure immediately after a long drive, you will likely get a falsely high reading. Because of this, manufacturers recommend the “cold inflation pressure.”
For the most accurate results, check your tires first thing in the morning or after the car has been parked for at least three hours. If you absolutely must check them after driving, generally add about 3 to 4 PSI to the recommended number to account for the heat, but make sure to re-check them once they have cooled down to be safe.
The Measuring Process
When you are ready to measure, unscrew the valve stem cap (the small plastic cap on the tire rim) and put it in your pocket so you don’t lose it. Take your gauge and press it firmly onto the valve stem. You will hear a brief hissing sound of escaping air; this is normal. Push the gauge down squarely until the hissing stops to ensure you have created a tight seal.
Once the seal is tight, the gauge will give you a reading. If you are using a pencil gauge, look at where the stick stopped moving; if you are using a digital one, simply read the screen. Compare this number to the PSI listed on your door jamb. If the number matches, replace the cap, and you are done. If the number is lower than recommended, you need to add air; if it is higher, use the small nub on the back of the gauge to press the center pin in the valve stem to release some air. Repeat this process for all four tires.
