How to check the air pressure in your tires


How to Check Tire Pressure with a Tire Pressure Gauge

Maintaining proper tire inflation is relatively simple and essential to the overall tire performance of your vehicle. A properly inflated tire will provide longer life, quicker steering response, better fuel efficiency and a smoother ride than an improperly inflated tire. Both underinflation and overinflation can cause headaches like premature treadwear and possible tire failure. The best way to ensure you're getting the most out of your tires is to check your tire pressure on a monthly basis. 

Knowing how to use a tire pressure gauge is very simple. Here’s how to check tire pressure and refill your tires.

Items You Need When Checking Tire Pressure

    Tire pressure gauge

    Air compressor

    Pen and paper

    Your tire pressure gauge can be digital or standard. Auto parts stores typically carry both. Many auto parts stores sell portable air compressors that run from your car battery or 12v power port. Alternatively, you can use the air compressor found at most gas stations. They usually cost $0.50 or $1.00 to use.

    HOW TO CHECK TIRE PRESURE

    1. START WITH COLD TIRES IF POSSIBLE

    Vehicle manufacturers specify PSI – literally “pounds per square inch” of pressure – assuming tires are cold. Tires are considered cold when the vehicle has been parked for three hours or more, or if the vehicle has been driven less than a mile (1.6 km) at moderate speed. PSI is the unit your pressure gauge uses to provide readings.

    2. CHECK THE MANUFACTURER’S RECOMMENDED PSI

    Look on the driver’s side door jamb or your owner’s manual to find the recommended cold tire PSI for your front and rear tires.  If you cannot find it, you should consult your vehicle dealer, manufacturer, or a qualified tire professional.

    3. WRITE DOWN THE PSI FOR EACH TIRE

    If your front and rear tires require different pressure levels, write down the correct PSI for each to avoid getting confused as you move around your vehicle checking tire pressure.

    4. CHECK TIRE PRESSURE WITH YOUR GAUGE

    Remove the valve cap from one of your tires. Then place the pressure gauge on the valve stem and press down hard enough so the hiss sound disappears and your gauge provides a reading. With a standard gauge, the air pressure will push a small bar out from the bottom of the gauge. Measurement units are etched into the bar. A digital gauge will show you the reading on a screen.

    Write down the reading and repeat this process for all four tires.

    5. FILL TO THE RECOMMENDED PSI

    Use an air compressor to refill any tires with low pressure. Many air compressors are different, so read directions carefully to be sure you’re using it correctly.

    If you’re using the air compressor at a gas station, be sure to park so that the hose will reach all four tires. Insert change into the machine until you hear the motor running. Fill each tire by placing the end of the hose over the valve stem and pressing on the lever.

    Using a gas station air compressor means your tires might be “hot. ”  If it is necessary to adjust inflation pressure when tires are “hot”, set their pressure to 4 psi (14 kPa) above the recommended cold inflation pressure. Recheck the inflation pressure when the tires are cold.

    After filling your tires, use the gauge to check pressure again. At this point, it’s ok if you overfilled the tires because you can always let some air back out. Never drive on overinflated tires. Overinflation can result in decreased traction, premature wear, and decreased impact absorption. 

    6. REPEAT: CHECK TIRE PRESSURE MONTHLY

    Make the above procedure a monthly ritual. Regularly checking your tire pressure is the best way to ensure your tires never dip far below the optimal PSI.

    TIRE PRESSURE GAUGE ACCURACY

    Accuracy matters and you should keep that in mind when choosing a gauge. For just a few dollars, you can find a quality, accurate tire pressure gauge that gives accurate readings. If you’re not sure which one to purchase, ask a professional technician which he or she prefers.

    A digital tire pressure gauge will provide accurate readings, but don’t forget that it operates on a battery. If you think having to replace the battery will prevent you from using it, it’s best to go with a standard gauge.

    It’s best to use your personal tire gauge versus those available attached to air hoses at service stations. Of all the pressure gauges out there, they’re the most likely to be weathered, and possibly inaccurate.

    CONTINUE YOUR JOURNEY

    There’s never a good time for a flat. That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.

     

    CONTINUE YOUR JOURNEY

    There’s never a good time for a flat. That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.

    See Details Find Your Fit

    How to Check Tire Pressure

    Learning how to check tire pressure is easy and inexpensive.

    Make it a part of your monthly maintenance routine in a matter of minutes.

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    Driving on improperly-inflated tires can wear out the tread and cause steering problems. That’s why it’s important to check your tire pressure regularly.

    Fortunately, checking tire pressure only requires two tools — a tire pressure gauge and an air compressor. Most gas stations have an air compressor so you only need to own one tool. The whole process is relatively quick, too. In a matter of minutes you’ve done a lot to ensure a safe and smooth ride.

    Before you begin, make sure the car has been parked for three to four hours so you get an accurate reading from the gauge. If you drive to a gas station to use an air compressor, try to find one less than a mile away.

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    Tools Required

    • Tire pressure gauge. A standard gauge, called a pencil gauge, can do the trick for less than $10. A digital gauge is also a good choice because it’s ergonomic and easy to read. There are also gauges (analog and digital) that attach to an air compressor hose so you can check the pressure and inflate the tire all at once.
    • Air compressor. Many gas stations have air compressors that cost 50 cents to $1 to use. A portable air compressor that plugs into the 12 volt auxiliary power outlet will also work; just be sure the air hose will reach all four tires.

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    Veronica Graham

    Step One: Determine Recommended PSI

    The driver’s side door jamb typically has a sticker with the recommended PSI (pounds per square inch) for the tires. Most manufacturers recommend 30 to 32 PSI for all four tires, although some cars will have different PSI recommendations for the front tires and back tires. If you don’t see the recommended PSI on your door jamb, check your owner’s manual.

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    Veronica Graham

    Step Two: Remove Valve Cap

    Unscrew the cap on the tire air valve and place it somewhere safe.

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    Veronica Graham

    Step Three: Check the Pressure

    Press the gauge onto the tire air valve straight on, and press it hard. This creates a tight seal around the tire air valve so you don’t accidentally release air from the tire. You’ll hear a hissing sound if air is coming out. A small bar with numbered notches will pop out of the pencil gauge with the tire pressure reading.

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    Veronica Graham

    Step Four: Inflate Tire

    Fill up the tire by pressing the air compressor nozzle onto the tire air valve in the same manner as the gauge — hard and straight-on to create a tight seal. Hold the nozzle onto the tire air valve for about 30 seconds to one minute, depending on how low the initial reading is. Repeat Step Three to get the new reading. Add or release air as needed to reach the recommended PSI.

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    Veronica Graham

    Step Five: Check Remaining Tires

    Repeat Steps Three and Four on the three remaining tires.

    Originally Published: April 16, 2020

    Veronica Graham

    Veronica Graham is a freelance writer in Arlington, Mass. Her work has appeared in The Washington Post and SheKnows. She's covered health, politics, high school football and everything in between. Graham enjoys learning about the world through a variety of lenses as a reporter.

    Air pressure in the wheels. When to measure and how to inflate

    Tire pressure significantly affects driving parameters: comfort, car handling, economy and safety. It is important to maintain the pressure recommended by the manufacturer and check it regularly. Let's figure out how to do it right.

    What causes incorrect tire pressure

    When driving on asphalt, incorrect tire pressure (both high and low) leads to a decrease in the contact patch with the road. An overinflated wheel clings to the surface only in the central part, which leads to its rapid wear. A poorly inflated tire, on the contrary, "sits" on the sidewalls, leaning on the shoulder areas of the tread and pushing the central part inward. Here's what it looks like:

    Both under-inflation and over-inflation in tires create many problems for the driver.

    Negative effects of excessive tire pressure:

    1. Increased wear of the central part of the tire tread.
    2. Reduced ride comfort, hardness of potholes and road bumps.
    3. Increased load on the car's suspension due to reduced tire damping effect.
    4. Risk of tire damage and herniation due to shock loading (getting into a pit or pothole).
    5. Reduced control stability due to reduced contact patch.

    Negative consequences of insufficient tire pressure:

    1. Increased wear of the tread sidewalls (shoulder areas).
    2. Severe deformation of the rubber when driving over bumps, which increases the risk of tire damage.
    3. An increase in tire temperature, which threatens to delamination of the carcass and can lead to tire explosion at high speed.
    4. Increased risk of hydroplaning on wet roads.
    5. Risk of tire breaking.
    6. Increased fuel consumption.

    Reduced pressure hits the driver's pocket hard: a pressure drop of 20% (which is not uncommon: it is enough, for example, to deflate the wheels to 1.8 atmospheres instead of the manufacturer's prescribed 2.2) reduces tire life by 25-30% and increases fuel consumption fuel by 3%.

    What should be the tire pressure

    There is no universal tire pressure: it depends on the size of the tires, the characteristics of the car (primarily weight) and road conditions. Therefore, it is important to follow the factory recommendations, maintaining exactly the tire pressure that the engineers expected when designing the car.

    The recommended pressure for your machine can be found in the operating instructions and on the sticker in the door frame. If, depending on the configuration, tires of several dimensions were installed on the car, then the pressure recommended for them may differ - look in the table for your exact wheel size. The manufacturer may prescribe an increase in tire pressure at the maximum load of the machine. For the spare tire (Spare tire), the required pressure is also indicated on a separate line - note that it is much higher than the standard one.

    Pressure units

    So, you have found the necessary pressure parameters, it remains to decipher them. In physics, pressure is measured in pascals, in real life - in anything: in bars, atmospheres, pounds-force, kilogram-force ... Drivers and tire workers usually use the term atmosphere, but such a unit is often absent on pressure gauges (pressure measuring devices) . Let's clear up this confusion.

    Atmosphere is a non-systemic unit of measurement, approximately equal to atmospheric pressure on the surface of the Earth. Since it has become widely used, it was necessary to somehow equate it with correct physical units. For simplicity, one atmosphere is considered equal to one bar, one kilogram-force and one hundred kilopascals.

    In addition to the technical atmosphere (at), there is also the physical atmosphere (atm), which is slightly larger. Again, for convenience, they are considered equal. But all these assumptions introduce an error, so if you need accurate tire pressure, measure it correctly - in pascals or bars. Moreover, manufacturers usually indicate the pressure in these quantities.

    Imperial pounds-force (aka PSI, “psy”), popular in the USA, is more difficult to translate, here you can’t do without a calculator. In the table, we have collected together all pressure units with exact values, and also approximately brought them to each other to simplify calculations:

    1 atm ≈ 1 bar ≈ 1 kgf/cm² ≈ 100 kPa ≈ 14.5 psi

    Pressure units

    Pascal
    (Pa)

    Bar
    (bar)

    Technical atmosphere
    (at)

    Physical atmosphere
    (atm)

    PSI
    (psi)

    1 Pa

    1 N/m²

    10-5

    10. 197•10-6

    9.8692•10-6

    145.04•10-6

    1 bar

    105

    1x106 dynes/cm²

    1.0197

    0.98692

    14.504

    1 at

    98066.5

    0.980665

    1 kgf/cm²

    0.96784

    14.223

    1 bar

    101325

    1.01325

    1.033

    1 bar

    14. 696

    1psi

    6894.76

    68.948•10-3

    70.307•10-3

    68.046•10-3

    1lbf/in²

    How to measure tire pressure correctly

    It is advisable to check tire pressure daily, before driving. But this is only possible with a very measured rhythm of life. In reality, checking at least once a month is already an excellent indicator for the average driver. But before traveling a long distance, checking the pressure and visual inspection of tires and rims should be done in any case.

    It is necessary to measure the pressure in cold tires, that is, before driving. During driving, the tires heat up, which increases the pressure by about 10%. Therefore, never release supposedly excess air from hot tires: after cooling, the pressure will be below normal. If you had to inflate a hot tire during a trip, inflate it 10% more than the nominal value, and check the pressure again when the wheels have cooled down - no earlier than 3 hours after stopping.

    Always check the pressure in all tires. Different tire pressures seriously affect handling and can cause the car to pull to the side. Do not forget about the "spare tire": it should always be inflated in case of an unexpected wheel change on the road.

    When tire pressure needs to be adjusted

    For long-term driving at high speeds (more than 160 km/h), car manufacturers advise increasing tire pressure by 0.2-0.4 bar from the recommended value. This will slightly improve the handling of the car, although it will negatively affect comfort. But such advice is relevant for driving on high-speed autobahns, and not for everyday urban use, especially in Russia.

    Before a long trip on a dirt road or a road with a muddy surface (mud, snow), it is reasonable, on the contrary, to reduce the pressure in the tires - this will improve the grip. In summer, it is worth limiting yourself to reducing pressure by 5-10% of the nominal value, and in winter - by 10-15%.

    Low-profile tire pressure

    The pressure in low-profile tires (especially non-standard sizes) must be monitored especially carefully. Low profile tires have two features: a low sidewall (profile) height and a large rim diameter. If the tire has the correct air pressure, only the tread is in contact with the road. Low pressure causes the sidewall of the tire to bend, causing it to touch the roadway and wear out quickly, up to complete abrasion. And punching a low-profile tire in a pit at low pressure is much easier.

    When inflating low profile tires, you need to focus on the pressure indicated for a full load of the machine and the maximum allowable pressure for a particular tire. It is indicated on the sidewall, next to the inscription max pressure, in one of the accepted units of measurement: kilopascals (KPA), bars (BAR) or pounds-force (PSI).

    How to measure tire pressure

    Modern cars equipped with sensors in tires and a TPMS (Tire pressure monitoring system) pressure monitoring system themselves monitor the pressure in each wheel and signal deviations, which is very convenient. If there is no such system in the car from the factory, you can install it yourself.

    But the old manual measurement methods are still in use. Firstly, any modern car compressor is equipped with a pressure gauge: by inflating the wheel, you immediately control the pressure.

    Secondly, there are compact hand-held pressure gauges: no need to unpack and connect the pump to check the pressure, and the measurement accuracy of such a pressure gauge is usually higher than that of a built-in compressor instrument. There are also modern digital pressure gauges on sale that allow you to switch pressure units on the fly and save readings in memory, which is very convenient.

    Finally, if you want to entrust all maintenance of the car to professionals, you can use the services of tire fitting. In Hyperauto car services equipped with tire fitting areas, experienced mechanics will accurately measure and correct tire pressure, assess the condition of the tire tread and perform any other work with the wheels.

    How to check tire pressure - we measure it ourselves + Video » AvtoNovator

    Tire wear, vehicle handling, and therefore driver safety are directly dependent on tire pressure. Therefore, it will not be superfluous to recall what it should be like and how to check tire pressure.

    What is tire pressure measured in - atmospheres, bars and pascals

    The main units for measuring tire pressure are atmospheres, at least as drivers and mechanics themselves are used to calling them. 1 atmosphere is approximately equal to 1 bar and 10,000 Pascals. But it would be too easy if pascals, bars and atmosphere were the only things that measure tire pressure. Today, more and more often at service points you can find pressure gauges with the PSI scale - this is a foreign pressure scale, which stands for pounds per square inch.

    These mysterious PSIs are just different from our atmospheres, for example, 2.0 PSI (or 20 on some scales) in terms of atmospheres or bars will give only 1.4. It turns out that one PSI is equal to 0.7 bar . So if you pump the wheels at 2.2 atmospheres, then you need to divide 2.2 by 0.7, and you will get the right amount of PSI, namely 3.2.

    How to check tire pressure - buy a pressure gauge!

    How can I check the tire pressure if there is no gas station or service station nearby? You can evaluate this parameter without a pressure gauge, focusing on the appearance of the tread after a long trip on a dry and relatively clean surface. These conditions are rare, but still - if both sides of the tread are clearly darker than the center, this means that the pressure is too low.

    The central part of the tread is clearly darker than the edge, which means that the pressure is too high.

    However, only a special pressure gauge, which is equipped with all vulcanization stations, service stations and gas stations, will show you true indicators. To measure the pressure, you just need to insert the end of the hose into the nipple. However, before check the tire pressure, let the car cool down after driving. For example, if you stop at a gas station and decide to pump up your tires, wait at least 15 minutes before doing so. Tire pressure should be checked at least once every two weeks or after every 2,000 km.

    Checking the tire pressure of the wheels - what does "underinflation" affect?

    Many drivers buy a pressure gauge for "home" use, so as not to look at the most inopportune moment how to check tire pressure. And this is a very correct step - sadly, but at different service stations and gas stations, pressure gauges can show different data .


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