How to check tire pressure
Keeping the proper air pressure in your tires is important. Here are a few simple steps to follow when checking your tire air pressure, as well as tips to make tire pressure maintenance easy.
1: Know your vehicle’s recommended tire pressure
It’s important to have your tires inflated to the pressure recommended by the vehicle manufacturer. For most vehicles, you can find the recommended tire pressure on the tire placard (a sticker with tire information) on the inside edge of your driver-side doorframe; otherwise, consult the vehicle owner’s manual.
The manufacturer provides the recommended tire pressure in psi (pounds per square inch). Keep in mind that it may list different pressures for the front and rear tires.
IMPORTANT: You should not inflate a tire to the maximum inflation pressure (found on the tire’s sidewall), since it may list a different pressure than what is recommended by the vehicle manufacturer.
2: Check the air pressure before driving
Be sure to check your tires’ air pressure when the tires are cool, or when they are the same temperature as the outside air and have not been driven on. Driving heats up the air inside the tires, which causes the air to expand and results in a higher pressure reading.
If you need to check the air pressure after driving on the tires, subtract 3 psi from the air gauge’s reading to account for the temperature difference, and then compare this value to the recommended tire pressure.
3: Inspect the valve cap
The valve cap helps to protect the opening at the end of the valve stem (the small tube that controls airflow in and out of the tire) and can help prevent air loss. (Learn more about valve stems.) You need to remove the valve cap from the stem to check the tire pressure; after you unscrew it, take a moment to inspect it.
Check the valve cap for cracking. Most valve caps will have a rubber grommet inside the cap to create a tight seal. If this rubber seal is cracked or missing, replace the valve cap as soon as possible.
4: Use a dependable air gauge to get the reading
Be sure to use a quality air gauge that will consistently provide correct readings. For convenience, we recommend buying one and keeping it in your vehicle. Your own gauge will likely provide more accurate readings than those at gas stations, car washes, and other public locations, as those can become inaccurate due to age, exposure, or abuse.
You can choose a traditional gauge with a meter, a pencil-type gauge, or a battery-powered digital gauge. Any of these options can provide you with reliable readings.
Firmly place the gauge’s exposed end onto the valve stem. If you hear a hissing sound after you place it on the valve stem, it is not centered correctly. Adjust your gauge to stop the hissing sound and get an accurate reading. Then compare the reading to the vehicle’s recommended pressure to determine if you need to adjust the tire’s pressure.
5: Adjust your air pressure
If you have determined a tire to be low on air (underinflated), filling it is fairly easy provided you have access to an air compressor like those found at many gas stations. With the compressor on, simply push the nozzle at the end of the air-hose on your valve stem to begin filling the tire with air.
Like with the pressure gauge, if you hear a hissing sound, it is not centered correctly. When the hose is properly centered on the valve stem, you’ll hear your tire inflating.
NOTE: As with public air gauges, keep in mind that public air compressors are often neglected or abused and may be difficult to properly inflate your tires.
On the other hand, if you have determined a tire is overinflated (a higher than recommended reading), simply depress the small brass needle in the valve stem to partially deflate (release air from) the tire. Most air pressure gauges have a protruded area reverse of the exposed end to make deflation easy.
6: Recheck air pressure and reinstall the valve cap
You’ll need to recheck the air pressure during adjustment to ensure your tires are filled to the recommended level. Lastly, always remember to reinstall the valve cap after you have finished checking or adjusting the air pressure.
Complimentary air pressure checks at Discount Tire
If you are having difficulty or prefer assistance with checking your tires’ pressure, stop by your local Discount Tire and take advantage of our complimentary air checks.