How to find the psi on a tire


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.

    Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links. Ratings and prices are accurate and items are in stock as of time of publication.

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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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    Veronica Graham

    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.

    3 / 7

    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.

    4 / 7

    Veronica Graham

    Step Two: Remove Valve Cap

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

    5 / 7

    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.

    6 / 7

    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.

    7 / 7

    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.

    Checking tire pressure, how often to check tire pressure

    20.01.2022

    Tires experience the greatest load in the car and constant contact with the road surface, which leads to their rapid tire wear. To extend the life of the rubber and at the same time ensure the safety of movement by car will allow maintaining the optimal pressure in the wheels, which can change under the influence of various factors. That is why, the question of how often to check tire pressure and how to do it correctly worries many car owners.

    Why is incorrect tire pressure dangerous?

    Regardless of the tightness of the tires, their pressure is reduced by 0.7 bar every month, even under ideal conditions. Inadequate pressure to the level recommended by the manufacturer not only shortens the life of the rubber, but also has more negative consequences. An excess or deficiency of this indicator is the cause of:

    • increase fuel consumption;
    • deterioration in ride and maneuverability;
    • decrease in depreciation and as a result, the appearance of discomfort during movement;
    • increasing braking distance;
    • reduce the adhesion of the wheel to the roadway;
    • wheel disassembly.

    This can be avoided by checking the pressure in the car's tires at least once a month. It is also recommended to check the pressure level before and after long trips. For each car, the manufacturer indicates its requirements for this indicator, which is indicated on a special plate located near the driver's door, on the fuel tank or elsewhere, depending on the brand of the car.

    Signs of incorrect tire pressure

    It is possible to determine the deviation of pressure from the normal level of this indicator, according to certain criteria. With insufficient pressure, the wheels begin to make a whistling sound during the entry into a turn, even at low speed, and when cornering at high speed, the flat tires “break down”. If the lack of pressure is observed only on one wheel, then the car begins to pull to the side.

    Inflated tires tend to have a sharp response to vehicle handling and terrain features, even when driving in a straight line. The car shakes noticeably on bumps and the side edge of the tire is more pronounced when entering a turn. In addition, with excessive pressure, the car rolls well on both flat and uneven surfaces.

    Pressure instruments

    The most common, convenient, and accurate method of measuring pressure is with a pressure gauge built into an air compressor. It can be found at service stations or specialized gas stations, or you can purchase a portable device for personal use at an auto shop. Depending on the version, there are three types of such equipment on the market:

    • Dial gauge is the most popular model, cost effective and easy to use. Equipped with a spring-type mechanism, the device has a minimum error and a long service life.
    • Rack and pinion - easy to use, budget device, characterized by high reliability, but inferior in accuracy to dial gauges.
    • With digital pressure gauge - a modern device with zero error, with all data displayed on the screen.

    In addition, there is an alternative to pressure gauges on the market - special electronic sensors made in the form of caps. They constantly determine the level of pressure in the tire and allow you to control the degree of inflation without additional equipment. Sensors with a transparent upper part are installed on each nipple. Depending on the pressure indicator, the transparent part is painted in a certain color:

    • green - normal pressure;
    • yellow - reduced;
    • red - exceeding the norm.

    The most accurate solution is offered by the Tire Pressure Monitor System (TPMS), which is already installed on many modern cars in factory conveyor conditions. In this case, the electronics independently determines the change in tire pressure and notifies about it using the on-board computer. Today TPMS is represented by several types:

    • direct system - provides for the supply of sensors to each wheel, which allows you to constantly monitor and display the actual amount of air in the wheels;
    • indirect - aimed at measuring the size of each wheel and the distance it covers in one revolution. Based on these ratios, the system determines the pressure level and detects the problem, which alerts the driver, but without transmitting accurate data.

    How to determine the pressure level?

    The main mistake that car owners make is to measure the air pressure in the tires after a long trip or after the car has stood in the sun for a long time. To get up-to-date data, check the tire pressure when the tires are cold. The best time for this is the morning hours. If the car has driven several tens of kilometers or stood in the heat, the results will not be correct.

    The level determination process itself is carried out as follows:

    • remove the cap from the air valve inlet on the wheel;
    • Locate the manometer fitting on the air valve;
    • press the pressure gauge knob until a characteristic hissing short sound appears;
    • follow the readings displayed on the pressure gauge;
    • , compare the obtained data with the pressure recommended by the manufacturer.

    If the pressure level deviates up or down, it is necessary to correct this indicator by dropping or increasing the amount of air in the wheels and reinstalling the cap on the air valve.

    This procedure must be carried out in each case for all four tires. With regular changes in pressure, it is necessary to have the wheels checked by a professional workshop.

    Most common tire pressures in bar and psi

    Different units are used to measure pressure. In Russia, this indicator is determined in bars (bar) and atmospheres (kg / cm²). Both measurement options are used as synonyms, since they are almost identical to each other: 0.9869 atm=1 bar.

    For foreign models, this parameter is determined by the ratio of pounds per square inch and is indicated by "psi", which differs from the bar value: 1 bar = 14.5 psi. Due to the difference in values ​​​​and the need to calculate the rate using formulas, many manufacturers indicate the optimal pressure in several units at a time. In other cases, you can use the standard table of unit ratios for the most common values:

    bar

    2

    2.2

    2.5

    2.7

    2.9

    psi

    29

    32

    36

    39

    42

    Tire pressure in summer and winter

    Anyone, even a novice driver, knows that tire pressure directly depends on the ambient temperature. When it gets cold, it drops, and during hot weather, on the contrary, it rises. As practice shows, deviations from the norm are observed even if the temperature fluctuates between 7–9 degrees.

    When using summer tires in the warm season, it is recommended to follow the manufacturer's recommendations, and when using it in autumn or winter, it is necessary to add about 0. 2 bar to these figures, since on average the wheel regularly bleeds air in the range from 0.07 to 0.14 bar.

    It is better to inflate outdoors, and not in a warm garage, since in this case the data will be incorrect and when the car leaves the open area, the tire pressure level will be lower than that which was inflated in the heat. In the summer, before checking and pumping, you should make sure that the car was not standing under the rays of the scorching sun.

    When pumping air into the wheels in the summer, it is better to under-pump a little. This is due to the fact that during the heat the roadway also heats up, which increases the contact patch with the surface and, as a result, friction. These factors provoke heating of the air in the wheel, its expansion and an increase in the atmosphere under the tire up to 15%. In winter, a different picture is observed. In severe frost, after the car has left a warm room, there is a sharp compression of the air, so it is better to increase the pressure in the tires of the car in winter.


    Tire pressure table by car brand

    07/23/2021

    Tire pressure is an important point during the operation of any vehicle and, in particular, cars. This indicator affects not only the wear rate of products, but also the quality indicators for driving a car, safety and comfort while driving, and the level of fuel fluid consumption. For this reason, every car owner should know how to correctly measure the pressure inside the tires and the tools for this procedure.

    Tire pressure measurements

    On the territory of the Russian Federation, the unit of measurement for air pressure for tires is 1 atm = 1 kgf / cm2. The value of this value is often equated to another unit - Bar. But in the US, this value is indicated in PSI, where 1 psi \u003d 1 psi. inch. This state of affairs affects the labeling and differences in the interpretation of indicators for different manufacturers. The designation of the maximum allowable pressure is in Kilopascals, where 1 kPa = 6. 895psi

    At the same time, when discussing the correct selection of the desired pressure value inside the tires, it is worth considering not the brand of tires, but the recommendations from the manufacturer of a particular brand, model and modification of the car. But not vice versa.

    Tire Pressure Tool

    Of course, special devices are used to understand the correct value and, at least, the current tire pressure reading. Manometers come in different types:

    • Pointer refers to the mechanical type of the spring type. The accuracy reaches up to 0.1 units.
    • Rack and pinion designed on the basis of a coil spring. Characterized by ease of use.
    • Digital is even easier to use with a digital display.

    But besides this, other types of devices will also help:

    • The indicator cap is a miniature device located on each wheel. Such a device is screwed onto the place of a conventional cap and, depending on the color, the pressure level can be clearly calculated.
    • External sensors-caps are electronic indicators of pressure and temperature inside tires. Differs in high accuracy of measurement.

    It should be noted separately that tire pressure measurements are carried out before the upcoming trip or after 5-8 hours of vehicle inactivity.

    Where are the pressure ratings?

    For the convenience of car owners, manufacturers indicate information about the required level of pressure on the front and rear wheels in such a way that you can always check it at the right time. Sometimes reference plates are located on the B-pillar or on the inner cap of the gas tank, as well as on the end of the door on the driver's side.

    Effect of seasonality on tire pressure

    In addition to the fact that all tires are divided into 3 main types: all-season, summer and winter, the inflation process in summer and winter will differ. This is due to the fact that inside any closed space, a pressure change of 0. 1 atm occurs with temperature fluctuations for every 8-10 degrees Celsius.

    Summer period

    In summer, one should take into account the heating of the road surface, which affects the increase in grip and friction of coated tires. Therefore, in this case, it is important to avoid the likelihood of tire explosions and other emergencies. When inflating tires in summer, the following factors related to tire pressure should be considered:

    • pressure increase occurs when the temperature of the surrounding air rises up to 10-15%, therefore, in such situations it is recommended not to “refill” the rubber;
    • during control measurements, an increase in the period for equalizing temperature conditions both inside and outside the wheels is taken into account; for this, it is desirable that the car stand at least overnight;
    • in the recommendations from the manufacturer, you can always get acquainted with the maximum allowable pressure in the tires of a particular brand of car, here you should take into account not only the season, but also the front and rear wheels.

    winter period

    The pressure drop in winter is caused by the cooling and cooling of road surfaces. This leads to a corresponding decrease in the stability of the tires on the road while driving. From here follow the basic principles of tire inflation in winter:

    • tire inflation and pressure control is carried out with a minimum idle time of 2 hours;
    • when leaving warm locations (for example, from a garage), it is necessary to calculate the temperature difference indoors and outdoors, in this case, every 10 degrees in the difference with respect to the normal pressure should be added by 0.1 atm;
    • in case of stability in ambient temperature, one should be guided by the recommendations from the manufacturers in winter weather.

    Regardless of the level of professionalism in car ownership, experts recommend using a pressure gauge at least once a month and before long trips. If there are frequent temperature fluctuations in the weather in any of the seasons, the interval should be reduced to 2 weeks.

    Low pressure

    With reduced tire pressures, contact between the wheel and the road surface occurs only at the extreme points. In visual terms, sometimes it is simply impossible to determine this, but this situation leads to the following negative consequences:

    • increased load on the lateral tracks of the tread, increased wear;
    • deterioration in grip with the road surface, delay in acceleration, increase in braking distance, increase in the likelihood of wear;
    • in the presence of high speed modes in the side parts of the tires, there is a wave-like transmission of movement, which leads to the impossibility of stabilizing the car in critical situations, the appearance of destructive vibration of the tire carcass;
    • increase in fuel consumption.

    High blood pressure

    When the required tire pressure is exceeded, only the central part of the wheels comes into contact with the road. This entails the following consequences:

    • reduced road grip, increased wheel stiffness, increased wear on center tracks;
    • collision with uneven surfaces leads to the risk of rubber rupture;
    • increased noise level, reduced driving comfort.

    Different tire pressure

    But even more dangerous situations and consequences arise with different pressures in all 4 or at least 2 tires. Indeed, in this case, there is a roll towards a less inflated wheel. In such cases, the consumption of fuel fluid increases up to 10%.

    Despite this, attention should be paid to cases in which pressure deviations in car tires by 10-12% help to help out on bumps, when passing surfaces with sand, viscous mud, and wet grass. That is, it is possible to increase the permeability. Pumping in a small range will help while moving on highways at high speeds. Sometimes a slight increase in pressure only on the rear tires allows you to carry heavy loads with the least problems.

    Pressure table for different car brands

    It is important to note that factory standards today are verified data that you should definitely focus on. They undergo numerous checks and tests, and the level of competition between brands makes it necessary to improve all indicators and the testing process. If you could not find recommendations from your car brand manufacturer, below we bring to your attention a table with the necessary data:

    25

    thirty

    35

    40

    45

    fifty

    55

    60

    65

    70

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    The size

    kgf/cm2≈BAR

    285/25-R20

    2. 9

    265/30-R19

    2.8

    215/35-R18

    2.8

    195/40-R17

    2.8

    165/45-R15

    2.5

    165/50-R15

    2.4

    155/55-R14

    2.2

    185/60-R14

    2.0

    175/65-R13

    1.9

    175/70-R13

    1.9

    295/25-R22

    2.9

    275/30-R19

    2.8

    225/35-R18

    2.8

    205/40-R17

    2.8

    195/45-R15

    2.6

    195/50-R15

    2.4

    165/55-R14

    2. 2

    175/65-R14

    2.0

    285/30-R19

    2.8

    255/35-R18

    2.7

    215/40-R17

    2.7

    195/45-R16

    2.5

    205/50-R15

    2.3

    165/55-R15

    2.1

    245/30-R20

    2.9

    265/35-R18

    2.6

    235/40-R17

    2.6

    205/45-R16

    2.4

    225/50-R15

    2. 3

    185/55-R15

    2.1

    275/30-R20

    2.9

    275/35-R18

    2.5

    245/40-R17

    2.5

    205/45-R17

    2.7

    195/50-R16

    2.4

    195/55-R15

    2.1

    255/30-R20

    2.9

    215/35-R19

    2.8

    255/40-R17

    2.5

    215/45-R17

    2.6

    205/50-R16

    2. 3

    205/55-R16

    2.2

    245/30-R22

    2.9

    225/35-R19

    2.8

    215/40-R18

    2.8

    225/45-R17

    2.5

    215/50-R16

    2.3

    215/55-R16

    2.3

    265/30-R22

    2.9

    235/35-R19

    2.8

    225/40-R18

    2.7

    235/45-R17

    2.4

    225/50-R16

    2. 3

    225/55-R17

    2.3

    285/30-R22

    2.9

    245/35-R19

    2.8

    235/40-R18

    2.6

    215/45-R18

    2.4

    205/50-R17

    2.4

    255/35-R19

    2.8

    245/40-R18

    2.6

    225/45-R18

    2.4

    215/50-R17

    2.4

    265/35-R19

    2. 9

    265/40-R18

    2.6

    235/45-R18

    2.6

    225/50-R17

    2.4

    275/35-R19

    2.8

    275/40-R18

    2.8

    245/45-R18

    2.5

    225/50-R18

    2.5

    245/35-R20

    2.9

    225/40-R19

    2.8

    255/45-R18

    2. 8

    235/50-R18

    2.5

    255/35-R20

    2.9

    245/40-R19

    2.9

    225/45-R19

    2.8

    275/35-R20

    2.9

    255/40-R19

    2.9

    245/45-R19

    2.7

    275/40-R19

    2.


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