Car Tire Pressure - Comprehensive Guide

What is Car Tire Pressure?

Car tire pressure refers to the amount of pressure air exerts inside the tire. It is measured in PSI, Pounds per Square Inch, the pressure resulting from a force of one pound-force applied to an area of one square inch. In SI units, 1 PSI is approximately equal to 6895 N/m2.

Car tire maintenance is one of the most important things you can do for your car from a safety and cost standpoint. As a car owner, you must know and sustain the correct air pressure in your car tires and be aware of the dangers of driving with ill-inflated tires. Maintaining the pressure in your car tires is both quick and inexpensive. All you need is a little information.

Measure car tire pressure

If the engine of your car is poorly maintained, you could still drive with some issues. Should you run out of gas, your car will eventually stop. If the battery is flat, it will refuse to start. These are serious and potentially expensive problems, but neither will cause a catastrophe on the road.

Driving with incorrect car tire pressure, on the other hand, means disaster could strike any time, at any speed. Under-inflated tires wear out faster, handle poorly and reduce fuel efficiency. Over-inflated tires are vulnerable to damage from road irregularities and create a bumpier ride. Overfilling your tires is just as dangerous as under-filling them, so you must know what is recommended for your car tires.

This article will show you how important one of the simplest parts of a car, four of them, to be exact, truly is.

How Do I Check the Pressure in My Car Tires?

Please do not assume kicking a tire is a valid check on its fitness. At the turn of the 20th century, car tires were far more fragile than they are now. Kicking one of those old-school tires could actually cause them to burst. You can check your car tire pressure in auto part stores, with a mechanic, at gas stations, or at home.

Digital Tire Pressure Guage

With a few bucks, you could get a simple, pencil-shaped tire pressure gauge at any auto parts store. A digital variant costs more money, but with added accuracy, a worthy expenditure. Knowing how to monitor your car tire pressure is critical to your safety and keeping your tires in good working order. To check your car tire pressure at home, follow the steps below:

Step 1: Check when the tires are cold

As tire pressure changes with the temperature, you should check when the tires are cold. Heat during the day or from the friction of the last drive could give inaccurate results. Check the pressure first thing in the morning or wait at least three hours after driving. This provides sufficient time for them to cool back down.

Step 2: Check the car tire pressure with the gauge

Take the valve cover off a tire and put the hose of the gauge over the valve stem. You will hear a quick hiss of air, the pressure gauge will show you the current PSI unless the tire is flat.

Step 3: Note the readings

Note down the PSI of each tire and compare it with the ideal PSI for the tire. For some vehicles, front and rear tires have different recommended PSI. It is that simple! Remember, getting a tire pressure gauge is cheap. Checking each car tire can be done in a matter of minutes. Knowing you are driving with properly inflated tires makes you a much smarter and safer driver.

You would be amazed at how wrong your tire pressure can be before it is noticeable by looking at it. Thankfully, no matter your car tire size and/or type, finding the recommended tire pressure is easy. For more on checking the tire pressure of your vehicle, watch this video.

Recommended read: Car shocks: Functions, symptoms, and tests

What is the Ideal Pressure for My Car Tires?

Having the correct tire pressure is extremely important for getting good gas mileage and the most life out of your tires. Maintaining your tires is pertinent to your safety and the overall performance of your car. So is knowing the right PSI for your vehicle.

Usually, the recommended pressure for car tires ranges between 30 and 35 PSI. For the ideal car tire pressure, look for the car maker recommendation, printed on a label inside your car. This label may be on the edge of the door, on the doorpost, or in the glove box. It usually details recommendations for the size of and pressure in the front, rear and spare tires. You MUST follow these guidelines.

Optimum Tire Pressure Recommendations

Even when you change tires, the same pressure guidelines apply to new tires of the same size. If you cannot locate the recommendations, check the sidewall of your tires for the maximum PSI. Kindly note that the maximum PSI listed on the tire is the maximum pressure the tire can hold, not the recommended pressure for the vehicle. Worst case scenario, you can call a dealership or find a reliable online source to find out the ideal PSI for your car tires.

Tire Pressure Guidelines

How Do I Maintain Proper Car Tire Inflation?

Knowing the recommended PSI for your car tires is not enough. You have to ensure you maintain the pressure by checking your tires regularly. When outside temperatures drop, like in the fall and winter, weather conditions cause your tires to lose air more quickly. Generally, your tire will gain or lose one PSI for every 10-degree change in temperature. A sudden drop of 30 degrees could lose your car tires three PSI overnight.

Experts recommend that you check your car tire pressure every time you inflate your tire, after each 10°F (5.6 °C) temperature change, and after every 30 days. Do not wait until the Tire Pressure Monitoring System (TPMS) light comes on before checking your car tire pressure. TPMS measures the amount of air in your tires to let you know if your tires are properly inflated. TPMS might be unreliable as:

  • It may turn on after the tire pressure is well under-inflated
  • The TPMS may not detect gradual air loss
  • It may not detect over-inflated tires
  • not be able to tell which tire is under-inflated
  • not turn on if the TPMS is not transmitting the signal to the dashboard.

Steps involved

In the event of a flat, you can inflate your car tire with a mechanic or at gas stations. Most gas stations have a manual air pump installed. You will need to check and monitor the PSI of your tire while actively filling it with air. At a gas station, please follow the steps below:

  1. Take the air pump and bring it over to your tire.
  2. Screw off the valve cover of your car tire.
  3. Place the air hose over the valve stem and press the pump lever. You will be able to hear the air passing through the hose and filling the tire.
  4. Release the lever to view the PSI on the gauge, and continue until you reach the recommended PSI. The gas station should have a PSI gauge attached to the air pump. If they do not, you can buy one at your nearest auto parts store.
  5. Once you have reached the ideal PSI, release the lever and remove the air hose. A little bit of air will escape, only a small amount. Replace the valve cover on the tire and return the hose to its spot on the air pump.
  6. Follow the same steps for the rest of your tires, and you are done. Note not to overfill!

If the gas station has an automated air tower, even better:

  1. First, enter your desired PSI on the digital display of the air tower.
  2. Depending on the design, air should start flowing automatically without you having to engage a lever.
  3. Attach the air hose to your valve stem just as you would with a manual pump. The machine automatically tracks the PSI with its built-in computer, so no need for a gauge.
  4. As it fills, the screen on the air tower displays the current PSI of your car tire.
  5. Once it starts beeping, the tire is done filling. Remove the hose and replace the valve cap.
  6. Repeat as necessary for the rest of your tires.
  7. Return the air hose to its spot on the air tower.


Should you need to deflate your tires due to over-inflation or increased pressure due to the weather, here is how to let the air out of your car tires:

  1. Remove the cap from the valve stem. Inside its center, you will find a metal pin.
  2. Get a flat-head screwdriver, place its top over the top of the metal pin, and press it inward. You will hear a hiss as the tire begins to release air through the valve stem.
  3. Remove the screwdriver, and keep your PSI gauge handy to check the tire pressure.
  4. Repeat until you get the ideal tire pressure. Make sure you attach the cap back to the valve stem.

There you have it, you have successfully deflated your tires!

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