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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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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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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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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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:
5 psi | Pressure units | |||||
| Pascal | Bar | Technical atmosphere | Physical atmosphere | 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. | 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 |
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.
Inconsistency with the prescribed tire pressure leads to a hefty hole in the family budget. Let's figure out how to keep tires in good condition, and what dangers warn the driver.
Every year cars require less care from the owner.
In the past, before each trip, the driver checked the oil and coolant levels in the engine, thoughtfully kicked the wheels. Those times are gone. Now the car owner calls in for maintenance in a timely manner, and fills in the washer fluid - if the vehicle does not present surprises, then the service ends there. They pay attention to the wheels only during the seasonal change or damage, forgetting that a mismatch in tire pressure can cause increased wear and even an accident!
The manufacturer always indicates the optimal pressure in the tires of passenger cars in the service book. This information is duplicated most often on the door pillar, for some models - on the inside of the gas tank cap or glove compartment. The numbers are clear and understandable. Pressure parameters are indicated corresponding to the allowable tire size at a certain load. Loading is shown by the number of passengers, so even the blonde from the joke can determine the correct value.
However, few people follow the wheels. It seems to be not blown away, we will assume that everything is fine!
If the tire is overinflated, its bearing surface becomes convex and there is increased wear in the center of the tire. Friction is slightly reduced and with it fuel consumption when driving on a flat road. But the savings are not justified, because in addition to damage to the tires, handling suffers. When driving at high speed, heating occurs, which is fraught with trouble, up to the explosion of the wheel.
The reverse situation is that there is not enough pressure. The sidewall of the wheel is excessively deformed, the rubber becomes unusable. There were cases when, when hitting an obstacle, the disk was deformed. There is an old "jeeper" trick: when driving off-road, the pressure is released to about 1 atmosphere. In the mud, the wheels begin to work more efficiently. But the pressure will be insufficient, then the rubber breaks off the rim, and fixing tubeless tires in the field is not so easy.
When leaving on a good road surface, you need to return the pressure to normal, which requires powerful compressors, the budget ones will push for 20 minutes and overheat.
Riding on under-inflated tires is dangerous: both handling and braking dynamics are reduced.
The conclusion is clear - car tire pressure control is needed every two weeks. Mandatory before a long run. Do not forget about the spare wheel, check its condition once a season.
Rule of thumb: pressure is checked on cold tires. When moving, the air heats up, and the pressure increases by 0.2-0.3 bar. If one side of the machine is in the shade and the other is in the sun, uneven heating occurs. It is not so easy to determine the correct adjustments, so in this case it is better to refrain from checking.
The outside temperature is also important. Tires inflated in the summer heat will show insufficient pressure in the fall. In winter, the pressure difference in the wheels of a car standing in a heated garage and on the street reaches 0.
1-0.2 bar. It is clear that the check is carried out where the car drives - directly on the street.
We habitually measure pressure in atmospheres, although bars appear on most pressure gauges produced abroad. Both bars and atmospheres have a dual meaning: physical and meteorological. Today we are interested in the physical.
1 bar = 1 dyne/cm 2 . Ding - a unit of force
In the system of units of the MKGSS, the technical or, as it is also called, the metric atmosphere appears. It is defined as the pressure produced by a force of 1 kgf per square centimeter. 1 atm = 1 kgf/cm 2 .
The difference between bar and technical atmosphere is small: 1 bar = 1.0197 kgf/cm 2 . Such differences do not go beyond the error of a household pressure gauge, so you don’t have to rack your brains on how to measure pressure - in atmospheres or in bars.
In the instructions of some machines may appear psi - pounds per square inch.
1 atm = 14.2 psi. Translating numbers is troublesome, so it's easier to get a pressure gauge with the right measurement scale.
It is impossible to determine the pressure in all the wheels of the car by eye. A slight difference from the prescribed one is practically invisible, modern tires hold pressure, even if they catch a nail. It is clear that this pressure is not normal. For example, in a wheel with several nails, 1 atm is stored, which only an experienced driver will feel. So you can't do without a manometer.
Inexpensive compressors are equipped with primitive pressure gauges, on the scale of which it is difficult to see tenths. Therefore, a manual pressure gauge is useful on the farm: it shows the data more accurately and it is easier for them to check the pressure.
Mechanical (pointer) pressure gauges are inexpensive and functional. There are additional buttons for resetting indicators and bleeding air.
Usually, 2-3 measurements are made with such equipment, since it is not possible to immediately press the pressure gauge against the tire nipple accurately. Mechanical equipment begins to show incorrect data when moisture enters. Mechanics are less precise than electronics. There is a subspecies of mechanical pressure gauges - rack and pinion. They look like a ballpoint pen, the readings are changed by a cylindrical spring. The thing is fragile, it is not in special demand, and therefore it is little represented in stores.
Electronic pressure gauges rule the roost. They are comfortable, there is a backlight, to switch the measurement scale, just press the button. It would seem - live and rejoice. But such pressure gauges also have disadvantages: they are more expensive than mechanical ones, they fail at low temperatures or refuse to work at all, they suddenly discharge, and they show a significant error when the battery is low.
The purchased pressure gauge is worth checking and comparing its readings with high-quality equipment.
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