Understanding Tire Pressure: What It Is, How To Check It

Tires that aren’t inflated properly can cost you a lot of money down the road. Tires that are over- or under-inflated can reduce your gas mileage, wear down unevenly, and even rupture, leading to a potentially life-threatening accident. Therefore, it’s important to periodically check on how inflated your tires are to avoid the danger. A tire’s inflation level is called “tire pressure.” 

In this guide, we’ll be going through what tire pressure is, how you can check it, and how often you should. We’ll also explain how you can find out what your tire pressure should be for your specific tires. 

What is Tire Pressure? 

Tire pressure is the amount of air that’s pumped into your tire, so it maintains a round shape that can still bend and adjust slightly on uneven surfaces. A tire's composition of inflated rubber saves the material costs that it would take to make a tire entirely out of solid rubber.

Tire pressure is measured in pounds per square inch (PSI), which should give you an idea of the high amounts of pressure contained within a tire. Most tires have a PSI rating on the side, which, according to Consumer Reports, is actually the maximum PSI that the tire can handle. You won’t want to always fill your tires to the maximum PSI, so you should instead check your owner's manual or sticker on the driver’s doorjamb to find the recommended PSI. The recommended PSI will be different depending on the type of tire and size of your car. 

How do I Check Tire Pressure?

Once you find out your tire's recommended PSI, you’ll need to do a couple of things before checking your tire pressure.

First, try to obtain a pressure gauge. Most pressure gauges look like a metal tube with a small bar that pushes out the end. If you don’t have a pressure gauge, most auto supply stores will sell them for only a few bucks. If you can’t access an auto supply store, you can also check your local gas station. If they don’t have pressure gauges for sale, they may have a pressure gauge built into their air pump, which is where you actually refill your tire’s air. Some cars may even have internal tire pressure monitoring systems. To learn more about these, check out our article on TPMS and how they work. 

Second, wait! To get the most accurate reading, wait until your car has been parked for around three hours so that it’s cooled. The best time to check tire pressure is when you’ve driven less than a mile at only moderate speeds. 

Once you’ve done this, you’re ready to check your tire pressure. 

Remove the cap from the tire valve and put the pressure gauge against the valve. Then, press down for a second or two. The small bar should push out from the other end of the gauge. The pressure can be found where the bar meets the metal part of the gauge. The pressure gauge at the air pump will instead have a dial where you can immediately get a reading. 

Once you’ve got a reading, write it down! (Or, if you're technical, take a photo of the tire gauge with your phone.) You have four tires, and the last thing you want to do is get your tire pressures mixed up and over-inflate a tire. 

How much air should you put in tires?

You should put no more air in your tires than your car's manufacturer recommends. Check the sticker inside of your driver's door for recommended PSI.

If you’re at a gas station, you can use their air pump, which is usually coin operated, to refill your tire pressure. If you’re planning to go into a mechanic or to have your oil changed soon, you can also have them check and fill your tires while you are there. Some auto shops will check tire pressure at no charge.

How Often Should I Check Tire Pressure?

Tire pressure should be checked about once every month and may vary by one or two PSI depending on the outside temperature. During the summer, PSI will typically be higher and during the winter, it will be lower. Therefore, during the change in seasons, you’ll probably need to deflate or inflate your tires to avoid bad gas mileage and uneven tread wear. 

Tires often lose pressure when seasons change, going from cold to warm and vice versa.

While you’re checking your normal tires, it’s also good to check your spare tire. Depending on the type of spare tire you have, your spare may have a much higher PSI rating than a normal tire. Check the owner's manual to see the recommended PSI for your spare. The last thing you want is to be caught with a flat tire and a flat spare!

ID 46361185 | Andrey Popov | Dreamstime.com

Photo 677543 | Tony Robinson | Dreamstime.com stick

Photo 31248757 | Karen Foley | Dreamstime.com main photo