How To Check Tire Pressure – 2021 Guide

| Last Updated: March 13, 2021

Have you ever noticed that your tires wear out too quickly? Or perhaps your car just doesn’t grip the road around corners.

Either way, your tire pressure could be the culprit.

So whether your tires are constantly underinflated or overinflated, learn why this situation is a concern and how to properly check your tire pressure.

The Dangers of Underinflated and Overinflated Tires

Before learning how to check tire pressure, you should first understand why your tires become overinflated or underinflated. By discovering the reasons behind these common tire impairments, you can comprehend why checking your tire pressure regularly is so important.

Why Are My Tires Underinflated?

Underinflated tires are the result of several different scenarios. Most commonly, tires deflate due to weather changes. For every 10 degrees that the temperature drops, your tires lose 1 to 2 pounds per square inch (PSI) of pressure. Also, your tires may deflate due to small leaks that happen from normal wear and tear. Air leakage from around the tire valve cap (the part where you deflate and inflate the tire) and between the wheel and the tire are two typical causes of underinflated tires.

While a slight deflation of 1 to 2 psi may not cause any problems at first, significant underinflation is one of the leading causes of tire failure. When the tire becomes underinflated by 5 PSI or more, more surface area of the tire touches the pavement. As a result, the tires build up more friction. This can lead to blowouts, tread separation, and increased wear on the tire.

Why Are My Tires Overinflated?

Overinflated tires are often the result of being overzealous with the air compressor when you fill the tire. Maybe you got distracted by something, didn’t have a tire gauge, or read that overinflated tires could improve handling or gas mileage. Whatever the reason, take note: overinflated tires are a hazard that puts the longevity of your tires and your safety at risk.

Contrary to popular belief, you probably can’t blow a tire just by putting too much air into it. To do this, you would have to put around 200 PSI in the tire, which is seemingly impossible. However, overinflated tires push the center of the tire tread onto the road while leaving the shoulders off the pavement. This results in poor handling and cornering, uneven tread wear, and an enhanced risk of a tire blowout, especially at high speeds.

How to Check Tire Pressure

Now that you understand the dangers of improperly inflated or deflated tires, you recognize the importance of checking them regularly. And even if you’re a novice or know nothing about cars, checking tire pressure is one of the easiest bits of car maintenance you can learn. Here’s how to do it.

1. Locate the Valve Stem

Located on the edge of the tire and sometimes sticking out through the wheel cover, the valve stem is the device that lets air in and out of the tire. Once you’ve found the valve stem, simply unscrew the valve stem cap.

2. Use a Tire Gauge to Check Pressure

The next step on how to check tire pressure is to buy or borrow a tire gauge. Stick gauges, or pencil gauges, are devices you press onto the valve stem. Then, a stick shoots out to tell you the current amount of pressure in PSI.

While seemingly simple in concept, many people misuse this device and let additional air out of the tire. When using a stick tire gauge, make sure you push the device firmly onto the valve stem. If done correctly, you shouldn’t hear any air hissing out of the tire except when you initially place the gauge on the valve stem.

Digital tire gauges are also a popular accessory that gives you a digital readout of your tire pressure in PSIs. For some beginners, this might prove an easier way to read your tire pressure PSI.

3. Determining What Your Tire Pressure Should Be

So you’ve got your PSI. Now what? Well, that depends on the proper pressure needed for your tire. The easiest way to find this information is:

  • To check your owner’s manual

  • Look at the placard information inside the driver’s side door frame

  • Search the sidewall of the tire for the proper PSI information (note that this is the maximum PSI, not an exact number)

Typically, passenger vehicles will have a tire pressure of between 30 to 35 PSI. However, this can change depending on the type of vehicle, how much you’re towing or carrying, and whether you’re off-roading. That said, your manual or placard will also list the maximum PSI so you don’t excessively overinflate the tires.

4. How to Deflate the Tires

If your tire pressure is above what the automaker or tire manufacturer suggests, you’ll need to let a bit of air out of the tire.

To do this, your tire gauge is your greatest ally. On a stick gauge, you can use the piece of plastic that comes out of the bottom of the backside of your gauge. Once you’ve determined which one you want, just push down on the small peg in the center. You should immediately start to hear the air rush out.

After letting some air out, check the tire pressure again with the gauge. Repeat this process until you’ve reached your desired PSI level.

5. How to Inflate the Tires

To inflate tires, you’ll need an air compressor—either one for home use or the one you’d find at a gas station.

  • Take the air nozzle from the compressor and press it firmly onto the valve stem.
  • Press the lever or handle to put air in the tire.
  • Use the tire gauge to check your tire pressure again and either add or release air until you’ve reached the proper level of tire pressure. 

Don’t forget to replace the valve stem cap when you’re done to keep dirt, dust, and grime out of the valve stem!

People Also Ask

Inflating and deflating your tires is one of the easier parts of routine maintenance on a car. But you may also have some questions about tire pressure or how often to check the air in your tires. If you have these concerns, don’t feel like you’re alone. Here are some of the top questions that people also ask about how to check tire pressure.

Do You Check Tire Pressure Hot Or Cold?

Tire manufacturers suggest that you check tire pressure when the tires are cold. Tires are considered cold when the car hasn’t been driven in three hours, before the temperature goes up in hot weather, or after driving less than a mile. If you have to check your tire pressure on hot tires, add 2-4 PSI more than you would on cold tires.

How Often Should I Check The Air In My Tires?

In normal weather conditions, you should check the air in your tires about once a month. However, cold weather can cause your tires to lose pressure more quickly, so you may want to check biweekly.

What is the Recommended Pressure of My Tire?

To find the recommended pressure of your tire, look in one of these locations:

  • Your vehicle owner’s manual
  • The placard situated inside the driver’s side door frame

The sidewall of your tire may also list the maximum PSI, but it won’t give you the precise PSI.

How Low is Too Low For Tire Pressure?

Anything below the tire manufacturer’s or automaker’s suggested PSI is too low for tire pressure. To add to this point, just consider that 20 PSI or less is usually considered a flat tire.

An ex-salesman of industrial equipment, Shawn used to drive nearly 60K miles a year just commuting to clients. He also has a little project Miata build going on the side. Safe to say, Shawn has slain a few tires in his days. He knows all about horrid road-noise, hydroplaning risks, and how much damage a bad alignment can do to your wallet. He enjoys helping us out and Chris always values his opinion when designing something new for the website.