How to refill tire pressure


How to Check Vehicle Tire Pressure and Inflate Tires

We all know that routine maintenance is important for everything from our computers to our cars. But sometimes, we fall short. One of the most neglected routine car maintenance tasks is to check tire pressures and inflate them as necessary. That’s why newer cars have tire pressure warning lights, or tire pressure monitoring systems (TPMS), that let you know when you have under- or over-inflated tires (when any tire is 25% underinflated).

Older vehicles don’t have this useful warning light. So, don’t wait for a rupture to check or change a tire. Use this guide to learn how to check the pressure (PSI) of your vehicle tires and how to inflate them to the proper air level.

Why should you check your tire pressure?

The number one reason why you should periodically check your tire pressure is SAFETY, but there are monetary and handling reasons as well:

  • Longer lasting tires
  • Improved handling and control
  • Reduced risk of accidents and blow outs
  • Better fuel economy
  • Reduced carbon footprint

Proper tire pressure (as recommended by the manufacturer) is needed to drive safely and efficiently. According to a 2009 report by the National Highway Traffic Safety Administration:

“…about 28% of light vehicles on our Nation’s roadways run with at least one underinflated tire. Only a few psi difference from vehicle manufacturer’s recommended tire inflation pressure can affect a vehicle’s handling and stopping distance. Poor tire maintenance can increase incidences of blowouts and tread separations. Similarly, underinflation negatively affects fuel economy.”

When your tires are underinflated, the tires get fatter, increasing their surface area. This causes high heat generation and extra resistance that could result in higher fuel costs, blown out tires, tire wear, and loss of control.

If you feel like you’re spending too much at the gas pump, it might be your tires. According to the US Department of Energy:

“You can improve your gas mileage by 0.6% on average—up to 3% in some cases—by keeping your tires inflated to the proper pressure. Under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop in the average pressure of all tires.”

In addition to safety and fiscal concerns, keeping your tires properly inflated will also reduce your impact on the environment. When your tires are properly inflated, you’ll pay less for gas, replace your tires less often, and improve your handling and stopping distance. You’ll also feel better knowing that you are emitting less carbon dioxide and other harmful substances into the atmosphere.

What is the right PSI level?

PSI stands for pounds per square inch. The recommended PSI for your vehicle’s tires is determined by the vehicle’s manufacturer and the recommended tire size.

One big question that we get is whether you should follow the recommended PSI level on the tire itself or the recommended PSI level printed in your owner’s manual or on the placard inside of door edge, glove box door, or fuel door.

Do NOT use the max PSI that is printed on the tire sidewall. This is not the recommended PSI level. The pressure amount on the tire is normally the maximum allowed pressure. The correct PSI level is almost always less than what you see printed on the side of the tire. Over-inflation can lead to poor handling and comfort, overheating and blow outs. Over 40 PSI is a dangerous level for most vehicles!

Make sure you always use the recommended PSI as provided in your owner’s manual and don’t go any more than 5 PSI over the recommended level. You should make sure, however, that your tires are appropriate for your vehicle. You can do this by checking the car’s owner’s manual or the placard that is on the inside of the driver-side door, glove box, or fuel door.

Most car tire pressure recommendations range from 30-35 PSI.

How often should I check tire pressure?

A question in many minds is when is the appropriate time and frequency for checking and inflating vehicle tires.

A quick google search will reveal a variety of different opinions and suggestions. Some say that you should check your tire pressure every 2nd visit to the gasoline station, while others say once every 3-6 months is OK.

Most tire and vehicle manufacturers, on the other hand, will say that you should check your tire pressure at least once every month, or every second trip to the gas pump. Your tires will lose around 1 PSI each for every month that goes by.

Unfortunately, not one answer will fit every situation. There are several factors that influence how often you should check your tire pressure, including:

  • The weather (hot and cold seasonal changes)
  • Driving frequency and distance
  • Weight carried or towed

Did you know that for every 10°-drop in temperature, you lose 1 pound of pressure?

If you have a leaky valve or a small puncture, you will lose air pressure much more quickly. This is one more reason why you should frequently check the tire pressure on all of your tires.

Since tire pressure constantly fluctuates, it’s important to check it periodically (at least once a month) and add air as necessary.

How to Check Tire Pressure

Finding out the tire pressure of your tires is incredibly easy. All you need is a pressure gauge (click here for additional items you should have in your vehicle).

Just make sure that you are checking your tires when they are relatively cold. If you check your tire pressure after a long drive, you will get an inaccurate reading since heat will temporarily increase the tire pressure reading.

Unfortunately, not all pressures gauges are created equal. Some are better than others. We recommend shelling out a couple extra bucks for a digital reader. The pop-up, stick-type versions are notoriously inconsistent and unreliable. A reliable gauge will be well worth the investment. Prices range from about $5 for the stick-type and about $30 for the digital and dial-type pressure gauges.

You can also check your tire pressure at most gas stations or auto repair shops. Discount Tire offers free tire pressure checks and inflation.

Here are the steps for checking your tire pressure:
  • Check the tire pressure when the tires are cold—first thing in the morning is best. If you’ve been driving for a while, you’ll want to wait several hours before checking your tire pressure.
  • Remove the caps to your tires’ air valve (keep them in a safe place, like your pocket).
  • Place the tire pressure gauge on the air valve firmly to receive a reading.
  • Take the tire pressure reading 1-3 times to get a good average and reduce the risk of anomalies.
  • Check the tire pressure gauge reading against the recommended PSI levels recommended by the manufacturer.
  • Add some air until your reach the recommended PSI level.
  • If the reading is above the recommended PSI level, push down on the air valve to release air. Check the tire pressure again. Release more air if necessary. If you release too much air, you can always add some air back.

It should only take you a couple minutes to check the air pressure of your vehicle’s tires. As soon as you restore tire pressure to the recommended levels, you’ll start experiencing the safety and savings that come with this regular maintenance task.

Watch this video for more information on how to check your tire pressure:

How to Inflate Tires

Here are the steps for adding air to your tires:

  • Remove the valve stem caps on all of your tires (keep them in a safe place, like your pocket).
  • Use an air pump to fill the tires. Even though it’s possible to fill your tires with a regular old bicycle pump, this is not the most efficient method. Instead, go to your local gas station that has a coin-operated air pump (ask the attendant if you can’t find it). You can also purchase your own automatic air compressor, but it will cost you around $50-$150.
  • Inflate your tires when they are cold. If you’ve driven more than a couple miles, you’ll want to wait until they are cold. The best time to refill your tires is first thing in the morning.
  • You can usually set the desired PSI level on the machine at the gas station (probably around 30-35 PSI). If your local gas station’s air pump doesn’t have this capability, then you will need to fill up the tire, check the pressure with your gauge, and then add or release air as necessary. Some air pumps will have a built-in tire pressure gauge. Once the PSI level is set, feed coins into the machine until you hear the air coming through. It will be pretty noisy.
  • You want to act quickly because you only have a few minutes before the pump turns off. Bring the tip of the air valve to your closest tire valve (or the lowest tire). Hold it firmly against the valve as you listen to the air filling the tire.
  • Make sure your vehicle is close enough to the pump so you don’t have to move and pay for another air session.
  • Give the pump some time to fill up your tires. If you pre-set the PSI on the machine itself, you will hear a loud beeping noise when the desired PSI is reached. If not, fill up the air for around 5-10 seconds and then check the tire pressure with your pressure gauge. Check the air pressure as you go and refill or release air as necessary.
  • If you go over the recommended PSI, you can release air from the tire by depressing the center valve pin with your tire gauge or a similar tool (a fingernail can also do the job). Release the air in small increments and check the pressure as you go.
  • When you have reached the desired pressure, make sure you check all your tires again with your pressure gauge. If all is well, you are done adding air.
  • Remember those valve caps we told you to keep safe. You’ll want to screw them back on now.

Remember, just one drop in PSI can lower your gas mileage by about 0.2%. For every 3-4 PSI units that your tire is underinflated, you are burning around 1% more fuel.

If your tires are flat, then you probably have a leak. Add air and see if you can drive around without the pressure dropping. If you hear air escaping the tire while you are filling up, then it’s time to replace the tire.

Tip: Learn how to use the air pump properly first. Some automatic air pumps at gas stations have a handle/switch that you need to depress in order for the air to flow. When you let go of the handle, a tire pressure gauge will pop out showing you the tire pressure. At the same time, air will be slowly released. If your air pump has this kind of handle, then you will want to hold down the handle for most of the time, periodically releasing it to check the pressure reading. Consult your own tire pressure gauge for accuracy.

When should I replace my tires?

If you check your tire pressure at least once a month as recommended, you’ll also get a good idea of the general condition of your tires and when you should replace them.

We recommend using the penny test:

Source: bridgestonetire.com

  • Take a penny and insert the top part of Lincoln’s head (head down) into one of the tire treads. If you can see his entire head, it’s time to replace your tire immediately.
  • Consider a replacement soon if only a small part of his head is cut off. You are good to go if Lincoln’s forehead is covered. Use the penny test on a few areas of each tire to get a more accurate reading.

Click here for more car maintenance tips. Click here for car winterization tips.


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More from Auto Simple

How to Properly Inflate Your Car Tires

Your car's tires play many valuable roles in the safety and function of your vehicle — from helping you navigate twists, turns, and stops like a pro to carrying the full weight of your car. That's why it's important to pay special attention to these essential components.

Fortunately, maintaining the proper tire pressure on your vehicle is one of the easiest yet most effective ways to care for your car tires. Learn how to check air pressure and inflate your tires with this helpful guide.

Why is Tire Pressure Important

Underinflated tires can not only reduce fuel efficiency, but it can also run the risk of getting into an accident, losing proper steering control, damaging various components of your vehicle, and more. If you notice that your tire's air pressure levels have dropped, it's best to prioritize inflating them as soon as possible.

How to Check Tire Pressure

Checking your vehicle's tire pressure is a relatively simple task. You'll want to start by purchasing a tire gauge. These vary in price depending on the type you choose (i.e., digital, basic, etc.) but can usually be found for well under $40. It's also essential to keep a tire gauge on hand, as some gas station air hose gauges are not always accurate. Many modern cars and trucks also display the tire pressure for each tire on the dashboard. Once you have your tire gauge in hand, it's time to determine the proper pressure for your vehicle. 

    Find the correct inflation level. To do this, you can either look for the recommended pressure on the sticker within your driver's-side door jamb or consult your car owner’s manual. This is the tire pressure specification when the tires are cold, meaning not driven for a few hours.

    Remove the valve stem cap from your tire. Some cars and trucks have green valve stem caps with an “N” on them - this means the tire is filled with nitrogen instead of air (air is mostly nitrogen). If your tires have these green valve stem caps, you can find some special stations that dispense nitrogen, but be aware that you can use normal air as well. The inflation pressure specifications are the same regardless if the tire is filled with air versus nitrogen. 

    Connect your air pressure gauge to the tire’s valve stem until you receive a reading.

    If the pressure level number seems unrealistic, remove the gauge and try again. This time, ensure that the indicator is connected firmly to the valve stem.

    It's not always possible to tell if a tire is underinflated by giving it a quick once over. So, check your PSI levels with a gauge each month and after extreme temperature changes. You'll also want to check your pressure levels when your tires have had time to cool down since air expands within your tires while driving.

    How to Inflate Your Car Tires

    How to Inflate Car Tires at a Gas Station

    Filling your tires with air at a gas station is relatively simple. Bring your tire gauge and some spare change since some are coin-operated and are not always accurate in their pressure readings. Try to make this the first stop if you are running errands so that your tires are still relatively cool from sitting for a few hours. Then, follow these steps:

    1. Park your vehicle close to the air dispenser so that you can comfortably reach each of your tires with the hose.
    2. Remove the valve stem caps from each tire.
    3. Use your tire gauge to check the air pressure in each tire.
    4. If the pressure is low, begin by adding air (one tire at a time) with the hose. 
    5. Stop periodically to ensure you haven't overinflated your tires. If you do overinflate, release some of the air slowly until you reach the proper amount.
    6. Replace tire valve caps once you've gotten them to the appropriate pressure levels.
    7. Enjoy the ride, and continue to monitor your tire pressure regularly.

    How to Inflate Car Tires at Home and On-the-Go

    1. Find a level surface under the shade.
    2. Remove the valve stem caps from each tire.
    3. Use your tire gauge to check the air pressure in each tire before starting. Remember that the tire temperature and air pressure will rise as you drive.
    4. If the air pressure is low and you have access to an air compressor at home, firmly press the air-hose onto your tire valve stem. You should start to hear air entering the tire. If not, confirm that the air hose and your tire’s valve stem are both securely connected.
    5. Try not to overinflate your tires. If you do, slowly release some of the air until you reach the correct amount of air.
    6. Replace the caps.

    Inflate Your Tires with Firestone Complete Auto Care

    Can't find an air filling station near you or just want some help? Head to your local Firestone Complete Auto Care. We'll give you a free tire inspection and refill your tires free of charge. And if you need new tires, we've got you covered there too!

    How to properly inflate a car tire / What to consider?

    Summer tires in Krasnodar at wholesale prices in stock and on order.

    Car tire is responsible for driving safety and comfort. It needs to be kept in working order. This is a prerequisite for long and safe operation. Not all drivers know how to pump up a wheel, we will analyze the nuances of this work in more detail.

    Why is it important to keep the tire pressure correct

    Tire pressure is an important parameter, it is he who is responsible for the main technical characteristics of the wheel. The car manufacturer calculates this parameter in advance and indicates it in the recommendations.

    If a tire is underinflated, this will lead to increased fuel consumption in the first place. This is due to a decrease in the rolling coefficient. Uneven grip with the road surface also occurs, leading to a decrease in traffic safety, this is felt in the form of more difficult driving. Tire wear increases, with a strong drop in pressure, the rim of the disc can cut the sidewall.

    It is also not worth pumping tires. The tire will wear unevenly, the middle part of the tread will suffer. Increased pressure can provoke an explosion and complete destruction of the tire on the road. In addition, the stiffness of the wheel will increase, and the braking efficiency will decrease.

    How often to check tire pressure

    Pressure checks must be carried out at least once a month. If there are sudden changes in temperature outside, it is necessary to check the parameter every two weeks. Be sure to check the pressure before every long trip.

    Visually inspect tires in the morning. If there are doubts about the quality of the pump, it is worth checking the pressure, if necessary, pump up the tire. Checking and pumping should be carried out on all wheels, different tire pressures can lead to loss of vehicle controllability.

    Be sure to check the condition of the spare wheel.

    Where to find the correct tire pressure for your vehicle

    Tire pressure is determined by the car manufacturer, he finds out through tests to what extent the rubber can be inflated. The data must be indicated in the documents for the vehicle.

    For greater simplicity, additionally indicate the parameters on the plate. It can be found on the A-pillar of the car or on the inside of the gas filler flap. In rare cases, a plate with the main technical parameters may be on the door. It remains to find a plate on your car and see to what pressure to pump tires.

    When you can pump the wheels

    There are certain pumping rules. They include not only data on how much air to pump into the tire, but also when to do it. The main requirement is to inflate the tire only after a long parking. The tire heats up while driving. According to physical laws, temperature directly affects gas pressure. Accordingly, immediately after the stop, the indicator will not be accurate.

    It is necessary to wait until the temperature of the air in the tire is equal to the outside. It takes 3-4 hours for this. After waiting so long, you can accurately measure the pressure. It is most convenient to do pressure measurement and pumping in the morning, after overnight parking.

    How to inflate a tire with your own hands

    Inflating a car tire is not difficult, but a beginner may have a few questions. We will analyze the stages of the process, in the end you will know how to properly pump up the wheel. To work, you will need a pump, you can use a foot or compressor. Now there are compressors that run on the cigarette lighter. If the pump does not have a pressure gauge, this device will also be needed.

    Let's walk through how to inflate a tubeless tire step by step.

    • We put the car on the handbrake. It is advisable to choose a flat place.
    • We take out the pump and pressure gauge. If the compressor is electric, we connect it to the power supply. Usually the connection is made through the cigarette lighter, just insert the tip of the cord into the cigarette lighter.
    • Unscrew the protective cap from the nipple of the tire. The cap must be placed carefully to the side so as not to lose.
    • Connect the hose tip to the wheel. To do this, the tip is simply put on the nipple, at the beginning you will hear the sound of escaping air. This is fine. Insert the tip completely.
    • After the handle of the handpiece is turned at an angle of 90°. So we fix the hose on the nipple.
    • Look at the manometer. It shows the pressure in the tire, if it is not enough, turn on the compressor. We are waiting for the pressure gauge to show a normal parameter.
    • Detach the tip. This must be done carefully, but quickly enough.
    • Screw on the previously removed cap.

    Further, all the described procedures are repeated on the remaining wheels, including the spare. Now the car is ready to drive.

    If the pump is foot operated, all steps are the same, except for the power connection. The air supply is carried out by setting the pump piston in motion, this is done by foot.

    Inflating a car tire is a simple job. This can be done by every car owner, even with no experience at all. The main thing is to know the basic rules, they are simple, it will not be difficult to fulfill them. But save time on a trip to a car service.

    About tire pressure - how to properly inflate wheels

    Optimum tire pressure is a guarantee of the safety of car passengers, as well as a guarantee of tire durability.

    Pressure measurement rule:

    The car must be “cold”, that is, before the measurement, the car’s mileage must be less than a couple of hours, the vehicle must travel no more than 2 km.

    When you need to measure the pressure urgently, subtract 0.3 bar from the measurement. The operation should be carried out before every big trip and more often than once every 30 days. It is important not to forget about the spare wheels: they also need to check the pressure level. The optimal level varies, so it’s worth asking the manufacturer for the exact figure, and it wouldn’t hurt to find the instructions for the car and look there. The value can be marked on the body compartment, gas tank and side pillar.

    Optimum pressure level

    It all depends on the weather and operating conditions. The nominal mark varies, for example, on how warm or cold it is outside the car. Drops in winter have a strong effect, so experts recommend adding 0.2 bar to the measurement result to objectively determine the pressure level.

    Why is proper tire inflation so important?

    If the pressure level on the front axle is less than the nominal one, then this will change the handling: the wheels will turn poorly. Incorrect pressure in the rear will cause the car, on the contrary, to move too sharply. Slip on wet pavement appears due to a decrease of 0.5 bar, since the contact of the tire with the road becomes less. A level of 2 atmospheres will lead to full contact. The lower the contact, the greater the risk. Therefore, the pressure affects the quality of the ride.

    In addition, the lower the level of inflation of the wheels, the greater the consumption of gasoline, and this promises financial losses. Too much pressure increases tire wear. Therefore, do not underestimate the importance of maintaining the pressure level set by the manufacturer. This can lead to a car accident.

    The ability of a tire to withstand loads is directly related to pressure. If the pressure is low, do not overload the car. When determining the optimal level, you do not need to focus solely on the tire load index.

    When to overinflate tires

    Raising the level is permissible if it is necessary to increase the carrying capacity of the car. But for most cars, this is dangerous by the rapid destruction of tires. For trucks, special tires are sold that provide an additional degree of protection. They have a special designation: XL, Reinforced or "C".

    The ability to accelerate the car depends on the inflation of the tires. To increase the speed, the pressure is increased. The ZR index on the tire indicates that with such a tire you can reach speeds of up to 245 km per hour. But we advise you to contact the manufacturer for details and clarify this indicator.

    A pressure of 3.2 atmospheres is optimal for tires with a T marker. An increase of this figure by 0.3 atmospheres is suitable for tires marked H, W, V, Y, ZR. Exceeding these figures is dangerous in many ways. Adequate pressure ensures proper weight distribution and longer life.

    Pressure reduction

    When the nominal pressure in the tires is lowered, the wear resistance becomes less because heat begins to be generated. Because of this, overheating and destruction occurs. Pressure below normal leads to a deterioration in indicators such as the ability to maneuver and elasticity.

    Note that tire pressure is an important property that must be monitored. Failure to pay attention to a detail that is so important for safety can lead to damage to the vehicle and to an accident. It should become a good habit for the driver to maintain the correct level.

    Do not try to determine the pressure yourself. Use a manometer. This device will accurately measure the indicator. For a novice car enthusiast, it is not easy to realize the level of pressure by internal sensations, it is important to contact the salons and ask to pump up the tires. A decrease in temperature by 8 degrees entails a decrease in pressure by 0.1 atmospheres.

    Tire care tips

    Don't underestimate the importance of tire condition. The life of people sometimes depends on the strength and wear resistance of wheels. In this regard, it is necessary to properly care for the tires.

    1. Check pressure regularly.

    As already noted, incorrect pressure can cause poor handling and tire damage. Let us remind you once again of the importance of checking the pressure on a car that has traveled no more than 2 km on the day of the control.

    1. Pay attention to appearance.

    Is there a valve cap? If not, then the nipple will be prone to contamination. Check tires for cuts, cracks, holes or bulges. All this speaks of dilapidation. There should be no foreign objects, including wires and glass. Remember that a tire with such damage is not suitable for use. Do not bring to the destruction of the tire on the go.

    1. What tire wear do you have.

    Wear leads to breaks. There is a fear of losing control when driving through puddles. Keep track of the remaining tread height. According to the traffic rules, it is forbidden to use a car whose residual height of the pattern is less than 1.6 mm (for cars), 1 mm (for trucks) and 0.8 mm (for motorcycles).

    For winter tires, the minimum residual tread depth is 3-4 mm. When the tire is used for too long, there is a danger that the handling on the water will be worse.

    1. Change your driving style.

    For motorists with an aggressive style, tires deteriorate much faster. It is also worth taking into account the climate and features of the road surface.


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