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.
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.
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.
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.
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.
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.
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.
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.
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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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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.3 / 7
Veronica Graham
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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Unscrew the cap on the tire air valve and place it somewhere safe.
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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
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
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.
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.
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.
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.
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%.
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.
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:
| Pressure units | |||||
| Pascal | Bar | Technical atmosphere | Physical atmosphere | PSI | |
| 1 Pa | 1 N/m² | 10-5 | 10. | 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. |
| 1psi | 6894.76 | 68.948•10-3 | 70.307•10-3 | 68.046•10-3 | 1lbf/in² |
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.
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%.
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).
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.
Vladimir Gavrilov
Estimated reading time: 3 minutes
2470
Category: Auto Maintenance
The design of modern tires has changed. They have strong sidewalls designed to maintain stability during maneuvering. If pressure begins to drop in such wheels, then they do not deform too much, and it is almost impossible to determine “by eye” when pumping is required. A pressure gauge usually comes to the rescue, but what if it is not at hand?
Many vehicles now have electronic systems that detect tire pressure differences using ABS.
They work according to indirect data based on electromagnetic sensors in the hubs and register a pressure drop of about 1 atm. If the pressure in one of the wheels has decreased, then it sags, which means that due to the reduction in diameter, its rotation speed increases. Sensors pick up the difference in rotational speed and the electronic unit issues a warning in the form of a yellow lamp. Next, the driver is required to find which of the four tires has a puncture.
This can be done by tapping.
The stiffness of the sidewall and the sound of the impact will tell you which wheel needs pumping. It is necessary to beat with a fist in a glove with the application of force. Usually, when hitting an inflated tire, the hand feels a strong elastic response, as if hitting a wooden table.
However, if the pressure in the tire is less than one and a half atmospheres, then the blow becomes deaf and soft, and the rubber springs more actively.
The sidewall flexes, and the driver can feel its compliance. The pressure difference between the four wheels is best recognized by blows.
When hitting, listen to the sound as well. If all tires ring the same, then you can go. But if at least one tire makes a dull sound on impact, then you should pay more attention to it.
Insufficient tire pressure affects the vehicle's coast. Any driver knows how far their car can roll at neutral speed. If the vehicle slows down more than usual on familiar straights, then it is possible that one or more wheels are not inflated as they should be.
Normally, a reduced coastdown is accompanied by a slight side pull of the machine, especially when one of the front wheels is flat. The car squats on a flat tire and forces the suspension to steer a bit.
As soon as the driver experiences this effect, it's time to look for the nearest gas station with a tire inflation system. In extreme cases, in a store at a gas station, you can buy a portable compressor along with a pressure gauge and inflate tires.
According to the standards, the pressure difference in tires can vary within 0.2-0.3 atm., But not higher. With a puncture from a nail overnight, the pressure drops by about 0.8 atm. and more, which is fraught with a decrease in controllability. Tire sag in this case is already noticeable, but not every driver can feel the difference, especially when the car is parked in the snow.
If you set off on an uninflated tire, a number of troubles can occur. The driver can drive on a damaged tire for a long time until the pressure in the wheel reaches 1.0 atm. Then the car will pull to the side. However, many drivers mistake this for the effect of the natural slope of the road and continue driving. In this case, the tire experiences increased loads for a long time, fuel consumption increases and tread wear increases. The rubber is abraded along the edges of the contact patch. The critical pressure is 0.5 atm. With it, the tire can be torn off the rim during braking.
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