How To Check Tire Pressure and Inflate Tires

How To Check Tire Pressure and Inflate Tires

What can happen from underinflated tires:

  • Might cause an accident
  • Increase tire wear which could burn through a set of $400 tires a year early.
  • Waste gas. How much gas? The Department of Transportation estimates that 5 million gallons of fuel per day are wasted due to low tire pressure. That's more than 2 billion gallons per year, just because people don't take the time to inflate their tires properly.

Checking Your Tire Pressure

Here's how to check the pressure in your tires with the least amount of fuss:

  1. Buy a digital tire gauge and keep it in the car.
  2. Find the tire pressure level required for your car. This information is usually on a yellow sticker in the doorjamb on the driver side. You can also look in the owner's manual for your car. It might call for different pressure levels for the back tires and the front tires.
  3. Check the pressure when the tires are cold. Tires heat up as they drive. They take about a half hour to cool down. Or you can just check the tires first thing in the morning.
  4. Unscrew the valve cap and set it to the side or in a pocket where you won't lose it.
  5. Press the tire gauge onto the valve stem. There might be a slight hiss as you press down on the valve stem and again as you release it. You only need to do this for a second or two, long enough to get an accurate reading.
  6. Read the tire pressure on the digital gauge. You might consider writing down the pressure of the tires as you go around the car. You can refer to this when you fill up the tires.

Now you can compare the tire pressure readings you got with the specified amount called for by the manufacturer on the doorjamb or in the manual. If the level of pressure in your tires is below the specified amount, you need to fill the tires with air.

For example, the sticker on the doorjamb may say that the recommended level is 32 psi (pounds per square inch). When you check your tire you find it is 29 psi. You need to bring your tire pressure up to spec. It's estimated that for every 3 psi below spec, you burn 1% more fuel (and add 10% more tire wear). It's not uncommon to be 10 psi below spec, whoch would waste 3% more fuel and increase tire wear by 45%.

Filling Your Tires

There are at least two ways to refill your tires to bring them up to specification. You can go to an auto parts store and get a portable air compressor. If you do this you can refill your tires at your house or in your garage. Some of these compressors are cheap and not really up to the task of quickly inflating your tires. Spend a few extra dollars to upgrade to a higher level compressor that connects to your battery terminals rather than running off the cigarette lighter.

Most people, however, will just refill their tires at the gas station. When you are at Micro Import Service for any type of maintenance or repair, we will always check your tire pressure. But temperature change can reduce the tire pressure, so you do not want to wait until your next visit to have your tires checked.

Adjusting Your Tire Pressure

Here are the steps needed to adjust the pressure in your tires:

  1. Pull your car in close to the air compressor so the hose reaches all four tires.
  2. Turn on the air compressor
  3. Remove the stem caps and set them to the side or in a pocket.
  4. Press the hose fitting down on the valve stem and press the lever. You should feel air flowing through the hose and hear it inflating the tire. This can take a little effort to hold the hose on the valve stem.
  5. Check to see when you have enough air pressure in the tires by releasing the inflation lever. The gauge on the hose fitting will show if you have approximately enough air pressure. you can check it again later with your own gauge. At this point, it is better to slightly overinflate the tire.
  6. Adjust the pressure in all the tires in the same way.
  7. Recheck the tire pressure with the digital gauge. If the pressure is too high, press the gauge down just far enough to release some air from the tire. Check it again.
  8. Replace the valve caps on all the tires.

If you get in the habit of checking your tire pressure once a month, you will eventually find a good gas station that has a conveniently located air compressor.

And you are always welcome to stop by our shop and our technicians will check the tire pressure for you.

Now it's time to enjoy improved fuel economy, reduced tire wear and - above all else - safe driving.

(article courtesty of