Your browser's Javascript functionality is turned off. Please turn it on so that you can experience the full capabilities of this site.
One of the greatest risks to your everyday driving safety is the one thing you can’t actually see: your tire pressure. Since inflation levels are invisible to the naked eye (unless your tire is almost flat), it’s important to understand how to find and maintain proper air pressure, and to be aware of the dangers of driving on over and under-inflated tires.
There is a tire pressure marking on the sidewall of your tires, but this isn’t the optimum air pressure for your tires, it’s the maximum.
The words ‘Max. Press. 35 PSI,’ for example, indicates the maximum pounds per square inch pressure needed for your tire to support the weight of its maximum load-carrying capacity. For everyday use, most passenger cars will have a recommended or optimum pressure of 30 or 32 PSI.
The handling characteristics change at max pressure
Since tires inflated to the max can’t give as much on the sidewall, you might see strong cornering performance, but it could be at the risk of your braking threshold. One quick corner and your back end could slide out.
Your tire life decreases at max pressure
When your tires are overinflated, the rubber rounds out at the top of the tire when you’re driving, and the centre will quickly wear out. You’ll also reduce your traction and you could even cause a blowout.
You’ll find the manufacturer’s optimum or recommended tire pressure for your car on a sticker in the door jamb, or in your owner’s manual. Some models even place the stickers on the trunk lid, in the console or on the fuel door.
When you drive with over-inflated tires, you risk:
Your tires can’t give as much on the sidewall, and precise braking could be compromised. You’d also be risking reduced traction.When you drive with under-inflated tires, you risk:
If you’ve been driving with your tires over-inflated or under-inflated, immediately deflate them to the manufacturer’s recommended pressure for your driving safety. If you’re not confident about how to check your tire pressure, follow our handy 5-step Guide to Checking Tire Pressure.
When your tires are consistently inflated to the recommended air pressure, you enjoy greater tire life, performance and safety.
Winter
When the temperature drops, air contracts and as the molecules get closer together, the reduction in volume causes tires to lose their pressure.
Before you know it, your tires are underinflated. Be sure to check your tire pressure regularly during the winter months.
Summer
Just as cold outside air causes the air inside your tires to contract in winter, warm outside air causes the air inside your tires to expand in summer. The rule of thumb (best understood as our American counterparts put it) is that tire pressure will go up approximately one pound per square inch (PSI) for every 10 Fahrenheit increase in temperature. So, let’s say your manufacturer’s recommend inflation level is 35 PSI, on one of those all-time hot August afternoons, your tire pressure could be somewhere near 40 PSI.
It's also important in summer to keep in mind that driving equals friction between the road and your tires, which equals heat, which equals…you guessed it…an increase in tire pressure. For this reason, regardless of the weather, your air pressure can increase about 5 PSI in the first half-hour of driving before stabilizing.
In the sweltering heat of summer asphalt at high speeds for long stretches, that number can rise, and not for the better.
Would you feel better about having expert eyes on your tires’ air pressure?
We can check your tire pressure for you and fill your tires with FREE air!
Find a Store
Was this article helpful?
Click on thumbs up or down to vote.
For many drivers, summer’s warm temperatures are an open invitation to venture down dusty roads, up winding trails, and across the great American highway system. Rising temperatures mean fun road trips with friends and family, but they also mean changes in your vehicle's tire pressure. Watch out for the dangers of over- or underinflated tires and gear up for a safer road trip season with Firestone Complete Auto Care by your side. With your new tire know-how, you may even be able to increase your car's fuel efficiency!
In general, tires lose or gain 1 PSI (pound per square inch) for every 10℉ change in temperature. Theoretically, your tires could gain 2 PSI over the course of the day if the temperature rises 20℉—a real possibility in many parts of the country.
Just look at average temperatures in Texas! In May, the average high sits around 80℉, with an average low in the 60s, reports Weather.com. Things cool off as you move a little north and west, with average highs in the 70s and lows in the 50s from North Carolina to Kansas.
From the hills of Virginia to the plains of Oklahoma, your vehicle is likely to encounter natural forces that will cause your tire pressure to go up and down throughout the day. So, why does it matter?
Proper tire inflation can lead to improved fuel economy, increased handling and safety, more responsive braking, and a smoother ride—all things that make for a great summer road trip.
While tires are designed to handle some fluctuation in temperature and PSI, they perform best when they start at the vehicle's recommended tire pressure. Just like eating a healthy, well-balanced breakfast sets your body up for success, inflating your tires to the recommended pressure sets your vehicle up for success!
When a tire is underinflated, more of its surface area comes in contact with the road. This can cause your car to feel sluggish and slow to respond, and may decrease your fuel economy.
“Under-inflated tires can lower gas mileage by about 0.2% for every 1 PSI drop in the average pressure of all tires,” reports the U.S. Department of Energy.
Underinflated tires can prove costly from a fuel perspective, but also when it comes to buying tires. Underinflation can decrease the lifespan of your tires and make them more vulnerable to damage—all leading to you having to buy more tires, more often.
When a tire is overinflated, less of the tire's surface area comes into contact with the road.
The tire will wear prematurely, possibly unevenly, and cause the car to handle and brake poorly, write the car gurus at CarTalk. The tire can also become rigid and inflexible, making it more prone to damage from potholes and other road debris.
Pro-Tip: Don't count on your electronic tire pressure monitoring system (TPMS) to light up if you have an overinflated tire. The warning light will only come on if a tire's pressure is too low, not too high.
When it comes to your vehicle's recommended tire pressure, there's no reason to guesstimate. Use our handy online tire pressure tool to find it in just a few clicks!
With this number in mind, grab your tire pressure gauge, get down to business, and check your tires. If your recommended pressure is 35 PSI, that means 35 PSI before you start driving, notes CarTalk.
To get the most accurate reading, check your tire pressure in the morning before hitting the road for the day, and adjust your tires based on that reading. Note that in the summertime, your reading may be impacted if the vehicle has been sitting in direct sunlight for a while or parked on hot pavement.
When life gets busy, head to your nearest Firestone Complete Auto for a fast, free vehicle inspection and tire pressure check. Our knowledgeable technicians will check the health of your current tires, inflate them to the recommended PSI, and guide you in buying new tires if yours show an unsafe degree of wear. Schedule an appointment online or stop by today. Our experienced tire technicians are here to set you up for a safe summer driving season!
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.
What should be the pressure in the tires of the car? Does it need to be adjusted and what will happen if the pressure is changed in one direction or another?
- I have a wheel, I have a wheel!
— Absolutely?
— No, only from below…
Humor from the Net
Let's start with platitudes.
The pressure must be as specified by the vehicle manufacturer. And since the average modern driver usually does not have such information, especially for him, a "cheat sheet" with the necessary numbers is hung on the middle pillar on the driver's side or on the gas tank hatch cover.
A relatively rare solution: the "reminder" is located on the gas tank flap.
A relatively rare solution: the "reminder" is located on the gas tank cap.
An important point: pressure should be measured only on cold tires. By the way, especially for pedants: cold tires are those on which the car has been without movement for at least 5 hours.
This "cheat sheet" nestled on the driver's door. An example of how tire pressure recommendations change depending on tire size.
This "cheat sheet" nestled on the driver's door.
An example of how tire pressure recommendations change depending on tire size.
Since car manufacturers allow the use of tires of different sizes, the pressure may also be different. In addition, the pressure in the front and rear tires has the right to both differ and be the same.
And there is no difference in the recommendations: what is in front, what is behind is the same.
And here there is no difference in recommendations: what is in front, what is behind is the same.
Related materials
Seasonal tire change: everything car owners need to know
Reduced pressure leads to an increase in tire deformation, its greater heating during wheel rolling, and accelerated wear of the outer tread tracks. Perhaps even a violation of the integrity of the frame. As a result, fuel consumption increases.
If you hit a hole in the road, the likelihood of damage to both the disk and the tire is higher.
Increased pressure is an overstrain of the cords, increased wear of the middle part of the tread. In addition, when driving on a bad road, the shocks that are transmitted to the suspension and body will become more noticeable for riders. When hit in a pit, the likelihood of a tire burst increases.
Uneven pressure on all four wheels is the worst thing! At the same time, the car, while driving, inevitably leads the wheels with lower pressure to the side - in fact, sideways movement begins.
Tube tires of the past required a weekly check, especially before the advent of butyl tubes. Then the pressure began to be checked less often, and nowadays, as a rule, they are limited to visual inspection.
Tube tires of the past required a weekly inspection, especially before the advent of butyl rubber tubes.
Then the pressure began to be checked less often, and nowadays, as a rule, they are limited to visual inspection.
In a good way, you need to check the tire pressure at least once a month. And before a long journey - just a must.
Related materials
Budget Tire Compressor Test: Wrong Bees
The air pressure in an enclosed space changes by approximately 0.1 bar for every 10 degrees of temperature change. This allows, having installed summer wheels in April, not to worry about the pressure in them until the end of August, when the air temperature begins to drop. Having pumped up the wheels at the end of summer, you can already reach the seasonal shift. But having installed winter tires in October, with the first frosts, you should check the pressure a couple more times: when the temperature drops to minus ten, fifteen, and when it goes over minus twenty. But from the middle of winter until the moment of changing the wheels to summer ones, there is again a period of relaxation.
Electronics are increasingly thinking for us. Now, a tire pressure monitoring system is being installed on parts of production cars. Moreover, some simply read the wheel speeds through the ABS sensors: after all, a flat tire rotates faster, since its radius is smaller than that of inflated wheels. There are also sensors that evaluate the amount of air pressure and send information via radio to the "brains" of the car. Such devices can also be purchased separately: sensors - in the wheels, and the receiver - in the car.
By the way, a lot depends on the road you are going to take.
The owner's manuals supplied with the vehicles indicate that it is recommended to increase the pressure by 0.2-0.3 bar before driving for a long time on expressways. We advise you to follow these recommendations on all cars: it will not get worse.
The operating instructions supplied with the vehicles state that it is recommended to increase the pressure by 0.
2-0.3 bar before driving for a long time on highways. We advise you to follow these recommendations on all cars: it will not get worse.
I don’t want to discuss overload: this, you see, is not the case. But, unfortunately, many deliberately overload the car several times a year, not only stuffing the interior and trunk to the eyeballs, but also attaching a trailer, which additionally loads the rear wheels of the tractor. In such cases, we advise you to increase the pressure in the rear tires by at least 0.2–0.3 bar. Tires will only thank you.
If you doubt the accuracy of your pressure gauge, then we advise you to check it immediately after leaving the tire shop, where you were set the obviously necessary pressure, to measure it with your own measuring device (separate or as part of the compressor). So you determine whether your pressure gauge is "lying" a lot. For the future, right on the dial, you can put a mark of the correct value.
Of course, it is better to have your own, known to be correct pressure gauge, but such a toy is not cheap.
Of course, it is better to have your own, known to be correct pressure gauge, but such a toy is not cheap.
If terrible ice caught you on summer tires, say, in the country, and you need to drive some distance along an absolutely icy road by any means, then you should reduce the tire pressure to approximately 1.6 bar. Is it bad for tires? Yes. But an accident will cost more. In addition, in such a situation, one does not have to wait for high speed, and overheating of tires at near-zero temperatures most likely will not happen.
Everyone knows what caused the excellent maneuverability of Soviet tanks? That's right: wide tracks, that is, low pressure on the ground. We, having an ordinary, non-all-wheel drive car, are also able to provide it with a similar cross-country ability.
If the wheels of the car sink into sand, snow or sticky mud, then it makes sense to lower the tire pressure. And not only driving, but also driven wheels.
We know from experience that it is often possible to get out of the "black spot" by reducing the pressure to 1.2 bar.
We know from experience that it is often possible to get out of the "black hole" by reducing the pressure to 1.2 bar.
In a very critical situation, if you know that you have a fairly narrow disc and a relatively wide tire (such a wheel has a lower chance of self-disassembly), you can reduce the pressure to 1.0 bar.
Stalled on wet grass? Try to relieve pressure.
Stalled on wet grass? Try to relieve pressure.
Pressure reduction is also useful in other cases - for example, to overcome diagonal hanging. If you reduce the pressure in the wheels on which the car rests, their height will decrease and there will be a chance to “hook” on the suspended wheels.
0197 
