When it comes to driving safety, tire pressure is always one of the hottest topics. Why does tire pressure matter? What the heck is that little annoying symbol on my dashboard? Should I under-inflate my tire during the winter? How often should I check my tire pressure?
We got tons of questions like this from our community, so for today, let's dive deep into the world of tire pressure, put our geeky glasses on and figure out everything you need to know about your tires.
1. What's The Recommended Tire Pressure For My Car?
The recommended tire pressure varies based on the vehicle makes determined by the manufacturer after thousands of tests and calculations. For most vehicles, you can find the ideal tire pressure on the sticker/card inside the driver’s door for newer cars. If there’s no sticker, you can usually find the info in the owner’s manual. Normal tire pressure is usually between 32~40 psi(pounds per square inch) when they are cold.
So make sure you check your tire pressure after a long stay and usually, you can do it in the early morning.
2. How To Check The Tire Pressure?
After knowing the proper tire pressure of your vehicle recommended by the manufacturer, you should check your tire pressure regularly to make sure that you are in good shape.
You can check your tire pressure in auto part stores, the mechanics, gas stations, and at home. To check tire pressure at home, you need:
As tire pressure changes with the temperature a lot, and recommended tire pressures are cold inflation pressure, you should start with cold tires if possible. We mostly check the tire pressure after one night's rest to avoid the heat from the friction of the last drive, and before the temperature goes up.
Unscrew the valve cap and press the tire gauge onto the valve stem hard enough until the hissing sound disappears.
There should be a reading as long as the gauge is well connected to the tire.
You can then note down the tire pressure of each tire, and compare them with the ideal psi you read from inside your driver’s door or in the owner’s manual. Make sure you read in detail, as for some vehicles, front and rear tires have different recommended psi.
If you find a tire underinflated, use the air compressor to fill your tires. You can either buy an air compressor in the auto parts store or use one in a gas station. Remember to rest your tires for at least half an hour to make sure they’re cold and the reading is accurate. If you have to fill your tires when the tires are hot, inflate them 3~4 psi above the recommended psi, and check again with your gauge when they are cold. It’s ok to overinflate a bit when filling the tires, as you can let the air out with the gauge.
After filling the tires, use your tire pressure gauge to check the tire pressure again and make sure they are in a good range.
Let the air out a bit if they are over-inflated by pressing the gauge harder on the valve stem.
3. How To Maintain Proper Tire Inflation?
Tire maintenance is essential for the overall performance of your vehicle, and we highly recommend that you check your tire pressure every time you inflate your tire, each 10°F (5.6 °C) temperature change, and every 30 days.
Be mindful that don’t wait until the TPMS(Tire Pressure Monitoring System) light come on before you check the tire pressure, as the normal TPMS may:
For more information about the tire pressure monitoring system, please check our post about TPMS: What is TPMS and Why Does it Matter?
Thus, we highly recommend that you check your tire pressure regularly, especially before a long drive or heavy load driving.
Also, temperature affects the tire pressure a lot, and we will explain it in the next section.
4. How Does Temperature Affect Tire Pressure?
First of all, the rule of thumb is for each 10°F (5.6 °C) decrease in temperature, the tire pressure will drop by one psi for most passenger vehicles. When it comes to commercial truck tires, which are often inflated to over 80 psi (twice as much as a passenger vehicle tires), the change of tire pressure according to temperature is doubled to 2 psi for every 10°F.
For the non-nerdy readers, just remember this rule of thumb and keep in mind that you will need to monitor your tire pressure during different seasons or a sudden temperature change. For those who want a deeper dive into how psi's are determined, here's the science behind it.
The equation we use to calculate the relationship between tire pressure and the temperature is called the
Ideal Gas Law. It is a good approximation of the behavior of many gases under many conditions.
(Appx1) It works well for most low-pressure gases. When applied to tire pressure calculation, the error is less than 1%.
First, we take the Ideal Gas Law equation and apply it to our circumstance:
where,
P = absolute pressure
V = gas volume in the tire
n = the number of molecules of gas in the tire
R = universal gas constant
T = temperature
Since we are trying to examine the pressure change according to the temperature, let's assume two tire pressures P1 & P2 at their set temperatures T1 & T2.
Given the n and R are both constants, and the gas volume in the tire is also a constant, we can take those constants out of the equation, and suddenly we get this straightforward one:
Let's say the temperature drops from 100°F to 50°F, the tire pressure at 100°F is 35 psi, so what's the tire pressure now at 50°F?
(the metric system is getting in the way, huh?)
Absolute Pressure = tire pressure + sea level air pressure (14.
7 psi). So,
Put all that into the equation,
So a 50°F drop in temperature lowers the air pressure by 4.5 psi, which is pretty much the same according to our rule of thumb.
5. How Does Tire Pressure Affect Driving
Both overinflation and underinflation affect your tire performance a lot, and serious problems might occur. According to NHTSA(National Highway Traffic Safety Administration), driving on underinflated tires increases a driver's chance of being in a serious accident by 300%. So how will a bad tire pressure affect driving safety? We will explain in detail below.
How tire pressure affects gripThe grip is mostly associated with the size of the contact patch between the tire and the road. An over-inflated tire radically decreases the contact patch while an under-inflated tire does the opposite.
A larger contact patch gives you more grip, and this is the exact reason why lots of racers will intentionally decrease their tire pressures to create a larger contact patch on a dry race track.
However, despite the fact that an under-inflated tire will cause more fuel consumption and improper tear and wear of the tires, for most daily commuters, it might cause an even scarier problem, which is hydroplaning.
Hydroplaning is a hazardous event when a layer of water builds between the wheels and the road surface, leading to a loss of traction that prevents the vehicle from responding to control inputs. (Appx2)
Hydroplaning occurs when the pressure of the tire pushing on the ground is equal to the water pushing back up on that tire. The size of the contact patch, given the force or the weight of the tire, is the same, directly affects the average pressure the tire's putting down on the road. The larger the contact patch (by deflating the tires), the less pressure it puts on that same area. So there's a causal relationship between your tire pressure and the possibility of a hydroplaning event.
Here's a more visual explanation of what is happening between a properly-inflated tire and an underinflated tire when driving on a wet road.
To avoid a hydroplaning event, ALWAYS inflate your tires properly. Also, check your tires' treads, which make the water flow around the tires more efficiently, and of course, driving slow is always a big plus.
How tire pressure affects tire wearThe contact patch directly decides the pattern of the tire's wear and tear. You don't want your tires to wear out prematurely just because you have an over or under-inflated tire.
How tire pressure affects fuel economyImagine you are a ball rolling on the ice, there's no friction between the two surfaces, how much extra force do you need to apply to keep the ball moving? Zero (Thanks, Newton). The same applies to your fuel consumption when it comes to driving on the road. The rolling resistance between your tires and the road significantly affects fuel economy, and by now we should all know the logic behind this, lower tire pressure leads to a larger contact patch, which causes higher rolling resistance, and thus, poor fuel economy.
A Michelin study showed that your tire is accountable for at least 1/5 of your total fuel consumption and a 1-bar of pressure drop (14.5 psi) would increase your fuel consumption by 3-5%.
6. Special Conditions For Tire Pressure Manipulation
There are of course circumstances where you want to manipulate your tire pressure to meet specific requirements. Like the aforementioned track race, or if you are driving on sand, mud, etc. However, as a daily commuter, we strongly suggest you regularly check your tire pressure, preferably once a week and anytime you might take a long road trip, and always keep the tires properly inflated!
Conclusion
Tire pressure is always a hot topic regarding driving safety, and it's important to keep an eye on the tire pressure to maximize fuel efficiency and safety.
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Appendix 1 - Ideal gas law - Wikipedia.
Appendix 2 - Aquaplaning - Wikipedia.
The recommended tire pressure is the pressure established by the manufacturer of your car as the optimal air pressure for your tires. Running your tires at the correct pressure is important because it keeps you safe, cuts down your gas bill, and makes your tires last longer. Each vehicle has its own specifications for tire pressure, but most fall between 28 and 36 PSI (pounds per square inch).
Be careful not to confuse the recommended pressure with the maximum pressure.
The recommended pressure is the one you should use when filling your tires, and, as explained above, you can find on your doorjamb or in your owner’s manual. The maximum pressure, on the other hand, is usually stated on the sidewall of the tire itself in small print near the tire’s bead (where the rubber abuts the rim). This measurement is provided by the tire manufacturer rather than the car manufacturer and is the maximum amount of pressure the tire can safely withstand.
Your tires’ max PSI almost always exceeds the recommended pressure. It isn’t advisable to fill your tire to this pressure for everyday driving. At max PSI, your car does not handle as well, braking is impaired, and you could risk dangerous blowouts. Over-inflation can also cause the center of your tire’s tread to wear out prematurely and reduce the lifespan of your tires. You may want to use the max pressure on a temporary basis if you are hauling especially heavy load or towing something.
Most manufacturers do not state a minimum tire pressure, per se. The recommended value is the amount of air that a tire needs for a car to handle properly and safely, and anything under that value is not recommended, so functionally the optimal value is also the minimum. Under U.S. law, vehicles are required to be equipped with tire pressure monitoring systems (TPMS) that warn the driver when tire pressure falls below 25 percent of the recommended PSI. This is considered severe under-inflation, but less drastic pressure drops are still considered moderate or mild under-inflation, and they and can still have negative consequences.
If your tires are inflated to a pressure that is below the recommended PSI (as shown in the manual or on the driver’s side doorjamb), your car will not operate safely. Under-inflation can cause the tire to heat up excessively, which can make the tread pull away from the body of the tire.
If this happens on the highway, it could lead to a blowout and a serious accident. There are also financial reasons for making sure your tires aren’t under-inflated. A low tire has more rolling resistance, which means the car has to work harder to move down the highway and consumes more fuel. Well-inflated tires are going to save you money at the pumps. Low tires also wear more quickly and unevenly, so you will have to replace them more often.
A tire pressure monitoring system (TPMS) uses either a direct sensor inside your valve stem or a combination of both software and other existing sensors in your vehicle to let you know when your tire pressure is outside of a safe range of pressures. If the pressure falls below the legally specified limit (25% of recommended pressure) an indicator light shaped like the letter U with an exclamation point inside it (representing the cross-section of a tire) will light up on the dashboard.
When you see this TPMS light on you should immediately check your tire pressure and make any necessary adjustments.
If you have further questions about tire pressure or any other aspects of your tires, find your nearest tire dealer to get some advice.
Photo: Shutterstock
adv.rbc.ru
See also
Tires are the only vehicle element that is in constant contact with the road. One of the main indicators of their serviceability is pressure. It affects not only fuel efficiency, but also safety.
As a rule, car manufacturers recommend maintaining tire pressures between 2.0 and 2.8 bar. But in practice there are situations when it is necessary to deviate from this norm.
adv.rbc.ru
Tire pressure should be checked at least once a month, there are several ways to do this. We understand why it is so important to observe the optimal pressure indicator and what it affects.
In this story:
Tire pressure is the resistance with which air "presses" on the inner area of the rubber. Properly inflated tires will last longer, give you better ride quality and improve your driving safety. If the pressure in the tires is too low or they are pumped over, then the car owner runs the risk of facing a number of problems: from buying new tires to the threat of an accident.
Properly inflated tires will last longer (Photo: Global Look Press)
Under-inflated tires are tires that are below the recommended pressure.
In this case, the contact patch of rubber with the road increases, which leads to increased friction or rolling resistance. A worn out outer edge of the tread can visually give out such a problem.
Increased friction with the road can cause the tire to overheat, slip and even burst. In addition, low tire pressure leads to:
When tires are over-inflated, that is, above the manufacturer's recommended rate, the contact patch decreases. As a result, the main friction with the road is taken over by the central part of the tire.
Excessive tire pressure leads to excessive sensitivity to road irregularities and the risk of tire damage, even destruction. Overinflated tires also cause the following:
Tatyana Eliseeva, an auto expert, master of sports of international class in motorsport, comments
For flat tires:
For overinflated tires:
Excessive tire pressure leads to excessive sensitivity to road irregularities and the risk of tire damage (Photo: Shutterstock)
For each car model, the manufacturer sets its own optimal tire pressure.
This indicator depends on the mass of the car, the speed of operation, the number of passengers (partial or full boarding), as well as the load on the trunk [1].
The recommended tire pressure can be found in the vehicle owner's manual or on one of the plates/stickers in the passenger compartment. They can be:
Tire pressure is measured in several units. In Russia, they usually indicate in kg / cm 2 (or atmospheres) and bars (bar). These two indicators are almost equal, which is why they are often used as synonyms:
Foreign models often use pounds per square inch (pound per square inch), or psi:
For convenience, car manufacturers can indicate pressure in two units at once - bar and psi.
Thus, the need to independently calculate according to the formulas disappears. Otherwise, you can do this in one of the online calculators or check the table of popular values.
| 2.0 bar | 2.1 bar | 2.2 bar | 2.3 bar | 2.4 bar | 2.5 bar | 2.6 bar | 2.7 bar | 2.8 bar |
| 29psi | 30psi | 32 psi | 33 psi | 35 psi | 36 psi | 38 psi | 39 psi | 41 psi |
Temperature has a significant effect on tire pressure: when it drops, the pressure in the wheels decreases with it. When the temperature drops by 10 °C, the tire deflates by an average of 0.
07–0.14 bar or 1 to 2 psi [2].
Temperature has a significant effect on tire pressure (Photo: Shutterstock)
Summer tires typically use manufacturer's recommended readings. But in winter, it is advised to add about 0.2 bar to these figures [3].
Experts also recommend checking and correcting tire pressure at outside temperature. In the cold season, swapping is best done not in a warm garage, but on the street. In summer, before such a manipulation, you should make sure that some of the wheels of the car were not under the scorching sun, while others were in the shade.
Sometimes the tire pressure needs to be adjusted according to the situation. For example, when the machine is fully loaded or a trailer is towed. For such cases, automakers, as a rule, separately indicate the optimal pressure.
But there are moments that fall into the category of extreme and non-standard (especially if before that the car most often drove around the city).
Automotive expert Tatyana Eliseeva analyzed the most common of them.
Leads to heating of the wheels, especially in summer, and therefore it is necessary to follow the manufacturer's recommendations before such a trip. We do not know what we will meet: patched road repairs or heavy rain. After all, for each of these situations, the recommendations will be opposite. Athletes can play with pressure when track conditions are known and engineers can always change the settings. For a long journey, the layman just needs to choose the average.
Tires must be bled off, especially on sand. The question is for how much? You can bleed up to 0.7 atm, but a not very experienced motorist can slip the wheels with an inaccurate movement, and if the driver turns the steering wheel sharply (for example, trying to catch on the edge of the track), then the tire can come off the disk. And such cases occur regularly.
At near-zero temperatures on packed snow, ice or sludge for new wheels (velcro or studded) it is better to pump the wheels a little so that water and sludge are squeezed out of the central zone of the contact patch and the tread is better have worked.
The wheel must be cleared for the tread to work. When it is clogged with snow, the braking distance and traction deteriorate greatly.
If the car has worn wheels, but with an acceptable tread depth for winter tires (4 mm), then you should not hope for the correct operation of the tread. Such a low checker no longer pushes the snow. In this case, it is necessary to reduce the pressure in the wheel, thereby increasing the same contact patch.
Photo: Global Look Press
On a country road, the weight of the machine will be an important factor. In this case, we select the pressure according to the load - specific indicators must be viewed on the central pillar of the body. There you will see something like the following recommendation: the more the car is loaded, the higher the pressure in the rear wheels should be.
But a badly broken road can lead to herniations, ruptures and tire damage. Therefore, if we increase the pressure, then we drive on a bad road as calmly and measuredly as possible.
Or we slightly deviate from the manufacturer's recommendations and raise the pressure not as much as the manufacturer recommends.
The main factor in changing the behavior of the wheel is not the pressure drop at altitude, but the presence of a large number of sharp turns and long braking. The tire will heat up not only from the loads, but also from the operation of the brake mechanisms. Therefore, the idea that due to low pressure it is necessary to increase the pressure in the tires is wrong, because the temperature of the wheel has a much greater influence in this case.
The recommended pressure is always given when the tires are cold. This means that the vehicle has not been driven for three hours or has traveled less than 1 mile (or one mile).
There are two ways to check tire pressure: on your own or at a workshop. In the first case, it is enough to use a public pump at a gas station or purchase a pressure gauge.
This tire pressure measuring device comes in three types:
Another option is to install special pressure control caps on each nipple. Such a gadget works as follows: the upper part of the cap is transparent and, depending on the level of pressure, an indicator of three colors appears in it. Green - the pressure is normal, yellow - the tire is flat, red - the pressure has exceeded the norm.
Photo: Shutterstock
The easiest way to monitor tire pressure is with the automatic TPMS (Tire Pressure Monitor System). Today it is installed on almost all models, and in some countries its presence is a prerequisite for releasing a car from the assembly line.
In these systems, the electronics automatically detect changes in the tire, and if the pressure drops below the recommended value, a warning signal lights up on the on-board computer screen.
There are two types of TPMS:
Car manufacturers recommend checking tire pressure every two weeks, but at least once a month. Indeed, even under ideal conditions (for example, the car is idle for a long time), the wheels lose approximately 0.069bar, or 1 psi, per month [4].
The pressure should be monitored before and after a long trip, during a sudden change in temperature (for example, during the first frost or warming), and also after changing tires or driving with a load.
Also, don't forget the spare wheel. Automakers advise servicing it at least as often as the main wheels. As a rule, it has its own optimum pressure values, which can be found in the operating brochure or information table.
| Make and model | Standard load front pressure | Rear pressure at standard load |
| Lada Granta (standard version) | 2.0 bar | 2.0 bar |
| Lada Vesta | 2.2 bar | 2.2. bar |
| Kia Rio | 2.3 bar | 2.3 bar |
| Hyundai Creta | 2.3 bar | 2.3 bar |
| Renault Duster | 2.0 bar | 2.0 bar |
Car tires TD KAMA of Russia 1. Car and tire manufacturer's recommendations for tire pressure
2. Pressure unit correspondence table
3. Why are deviations in tire pressure dangerous?
- Risks of insufficient tire pressure
- Risks of high tire pressure
4. How does tire pressure affect driving comfort and safety?
- Strength increase due to pressure
- Tire pressure for driving on the highway
- Off-road pressure
- Pressure and fuel economy
5. How does tire pressure depend on the season?
- Winter tire pressure
- Tire pressure in summer
6.
How to check tire pressure?
7. How often should blood pressure be measured?
Headed out on the road? Check tire pressure. Permanent advice, which, alas, is often forgotten. In the meantime, properly inflated tires make driving comfortable, driving safer, and tire life longer. What should be the pressure? What are the dangers of over-inflated or under-inflated tires? We have collected answers to all questions, as well as useful tips, in one article. Everything written below will help you not only make your trip safe, but also save your budget. How? Read and level up.
What should be the pressure?
Vehicle and tire manufacturers recommendations
So, let's start with the banal. Each car manufacturer has standards and recommendations for the level of inflation pressure in tires. It's always best to stick with them. You can find the numbers you need:
* In the vehicle owner's manual
* On a special sticker inside the car (usually on the car door, B-pillar or gas cap)
* In the form of a QR code (relevant for the latest models, especially premium ones; the sticker with the code is located in the same places)
These cheat sheets contain all the information you need.
The manufacturer stipulates not only the optimal level of internal tire pressure, but also the limits to which it can be increased or decreased relative to the norm. The amount of pressure depends on the size of the tires, on some cars the recommended pressure for the rear and front wheels differs. To summarize, for most passenger cars, the recommended constant tire pressure ranges from 2-2.5 atmospheres. This is the norm not only for a comfortable and safe ride, but also for fuel economy.
Tire manufacturers also indicate pressure on the label. But there is an important point here! The number on the sidewall of the tire is not the norm to strive for, but an indicator of the maximum pressure that the tire can withstand and not burst.
Correspondence table for pressure measurements
Tire pressure is measured in two units: atmospheres (or bars) and psi. Bars are the most common, it is in them that the pressure is measured in gauges in tire shops and gas stations.
However, in some countries it is psi that is used - pounds per square inch. To avoid confusion, it is worth remembering that one psi corresponds to 0.068 bars.
Why are deviations in tire pressure dangerous?
Tire pressure affects how long tires last and how quickly they wear out. And not only. If the tires are over-inflated or, conversely, under-inflated, then their critical properties such as traction, vehicle directional stability when driving, handling (especially when cornering and on uneven surfaces), braking distance and resistance to aquaplaning will change.
Why is this happening? To answer this question, elementary knowledge of physics is enough. With the right gas pressure from the inside to the tire, the tire retains exactly the shape that was intended by the manufacturer. The contact patch of the tire with the road is also optimal, because the tread at optimal pressure also retains its shape and the necessary degree of flatness so that its pattern moves along the surface as it should (see figure).
The most dangerous situation is when there are different pressures in different wheels of a car. Yes, some manufacturers allow different pressures in the front and rear wheels, but in pairs, tires on the wheels of the same car axle must still match. If the pressure is not the same everywhere, then the car, when driving, will roll towards the “sagging” wheel - that is, the one where the pressure indicator is the lowest. Such a situation is a reason for technical inspection. If one of the tires loses pressure, it may be damaged. A change in pressure can also be the result of a misaligned wheel rim or a defective spool causing air to leak.
- Risks of insufficient tire pressure
Tires with low internal pressure or, in simple terms, under-inflated tires lose their shape when driving. They become softer, more pliable, and the weight of the car, especially at speed and when cornering, makes them literally sag and sag. What does it threaten?
Uneven wear.
The side treads wear out faster than the middle tread because the tire has more contact with the road due to tire deformation.
Rolling resistance increases, which causes the tire to heat up more.
Acceleration time is increased.
Increased fuel consumption.
Threatening the integrity of the tire carcass and its rubber, especially in the side parts, which can lead to sidewall rupture. This can be warned by a worn strip that appears around the entire circumference of the tire - this is evidence of chafing of the cord threads.
Risk of tire dismantling. An under-inflated tire may come off the disc seat.
Tires deformed by long-term use at low inflation pressure become unsuitable for further use. Even if the pressure in them is brought to normal, the risk of rupture in the weakened parts remains. If you want to avoid unnecessary expenses - do not strain the tires.
- Risks of high tire pressure
With increased tire pressure, the part of the tread that should be flat and provide reliable traction becomes convex, literally swells up like a ball. As a result, the contact patch of the tire with the road is much smaller than planned by the manufacturer. Why is it dangerous?
The tread wears unevenly, faster in the middle than on the sides.
Decreased grip and handling.
Due to the reduction in the area of contact between the tire and the road, the braking distance increases.
If the tire pressure is too high, the tire runs the risk of exploding.
Long driving on tires with high pressure overstresses the cords, such a tire will last much less.
The deformed contact patch of the tire with the road interferes with the effective removal of water, as a result, hydroplaning can occur on a wet surface.
How does tire pressure affect driving safety and comfort?
Sometimes the pressure in the tires still needs to be lowered or increased. It depends on certain driving conditions or the quality of the surface. For a short period of time, this will improve the driving characteristics of the car and driving safety. Of course, everything is within the manufacturer's recommendations, however, even small changes can greatly affect driving comfort.
- Increasing tire strength due to pressure
A slight increase in pressure can slightly raise the "tensile strength" of tires under excessive loads. Yes, overloading the car is bad, but sometimes you have to, especially when the summer season is on the nose. This is especially true for a car with an attached trailer, which increases the load on the rear wheels. Tires at least on the rear axle in this case, it is better to additionally pump up 0.2-0.3 bar. From the additional load, they still “sag” a little.
- Tire pressure for highway driving
Long and high-speed races on highways for tires are a strong test. Therefore, even the manufacturers of many cars advise in the operating instructions: before a long trip on a flat road (more than an hour at a speed of 115 km / h), it is better to slightly increase the tire pressure. The increase should be small - 0.2 atmospheres (bar). This recommendation also takes into account the fact that the pressure in the tire itself will increase from the heating of the tire.
- Off-road pressure
Tire pressure adjustment can help you get through difficult terrain. Driving on sand, snow, mud and wet grass will be easier if you lower the tire pressure a little. This maneuver will increase the contact patch of the tire with the surface, increase grip, and the car will be less likely to get stuck and skid. The main thing is to keep a low speed, and when the difficult section is left behind, restore the correct tire pressure again.
- Pressure and fuel economy
There is a myth that when the tire pressure is higher than normal, fuel consumption decreases. It really goes down, but it's not worth it. The savings will be only less than 5%, but driving comfort will drop significantly. The fact is that the tire becomes stiffer under excessive pressure, so that you and your passengers will feel all the bumps and bumps in the road. The point in saving on fuel is also lost because with constant driving on overinflated tires, the tires themselves wear out faster and more likely to require replacement costs.
How does tire pressure depend on temperature?
In winter and summer, the pressure in car tires may differ. This directly depends on the physical properties of the gas with which the tires are inflated. We all remember from school that at high temperatures, gas tends to expand, and at low temperatures, on the contrary, it contracts. Therefore, even if the tires were inflated recently, with temperature changes, this very pressure will change, and noticeably.
On average, for every 10ºC, the air pressure in the tires changes by 0.1 bar.
- Tire pressure in winter
It is especially difficult to maintain constant tire pressure during cold snaps. Therefore, in the fall, changing summer tires to winter tires, checks must be approached carefully. It should be checked during the first frost and after the temperature drops well below zero. Most likely, the tires will need additional pumping. Keep in mind: in a warm garage or in a closed parking lot, it is difficult to catch the pressure drop in the tires. It will happen when you go out into the cold. Therefore, it is better to check and inflate tires after parking in the open air.
- Tire pressure in summer
Summer tire inflation is recommended to be carried out in a warm spring with a margin for the summer and at the end of summer before changing seasonal tires. However, this does not exempt from checks. The fact is that the warmer it is, the more the air in the tires expands - and the sooner it “comes out” through the chambers.
In addition, pressure can drop with even microscopic tire damage, and in summer this happens even faster.
How to check tire pressure?
1. The pressure gauge is your best and indispensable friend in this matter. It can be either portable, up to the size of a key fob, or stationary, installed at a gas station, in a tire fitting room or other specialized car service facilities.
You can buy your own car pressure gauge at any auto parts and accessories store. They are pointer, mechanical or electronic. Not only its price, but also its accuracy depends on the class of the pressure gauge. The pressure gauge is mandatory installed on the compressor for pumping wheels - it is he who allows you to adjust the pumping process and the required amount of air supplied to the tire. But it can also be used separately to determine the existing pressure.
It is easy to check the accuracy of the manometer. Use it immediately after the tire fitting, where you will adjust the inflation pressure in the tire to the desired value, and just check the readings.
2. Automatic tire pressure monitoring systems. For example, premium cars are equipped with direct pressure sensors that are installed directly into the wheel rim. Sensors measure tire pressure and temperature, and the information is sent to the on-board computer. When pressure indicators change, a warning signal is received, or information is displayed on the computer panel in digital and alphabetic form. Similar direct control devices can be purchased and installed separately: pressure control sensors are installed in the wheels, and the receiving device is installed in the passenger compartment.
A similar system is part of the anti-lock braking system (ABS), but it works differently. The ABS system does not measure tire pressure, but wheel speed, and draws conclusions. The fact is that when the pressure decreases, the diameter of the tire changes, and the wheel starts spinning faster in order to “catch up” with the rest. The system captures these changes, checks them against valid values stored in memory, and informs you of the mismatch.
3. Indicator caps are screwed onto the tire valves. These pressure sensors are transparent on top, and this part serves as an indicator: the change in color indicates the current state of the wheels. The obvious disadvantages of such a control system are that it is impossible to evaluate the change in tire pressure during movement with its help; a stop and a visual inspection are necessary.
How often should the tire pressure be checked?
Manufacturers recommend checking tire pressure once a month. But this is the minimum. Of course, under extreme operating conditions and sudden changes in temperature, it is not worth the risk and you need to check more often. And before a long journey or planned loads, checking the internal pressure in the tire is completely mandatory, even if it is extraordinary.
Important: pressure measurement is carried out only on cold tires - that is, those that have remained without movement for at least 5 hours.
5 most important findings
1. Tire pressure affects ride comfort, vehicle handling and your own safety.
2. Under-inflated tires wear out faster, can burst at the side and heat up much faster when driving. With prolonged use of tires with reduced pressure, tires are completely deformed so that they can no longer be restored.
3. Overinflated tires lose reliable grip, and the car loses controllability. In addition, when driving on overinflated tires, the braking distance is greatly increased, and each bump becomes more noticeable.
4. Check tire pressure at least once a month, and definitely before every long trip. A pressure gauge or automatic tire pressure monitoring systems will help with this. The pressure check is carried out on "cold" tires that have not been on the move for at least 5 hours. Temperature fluctuations, frosts, long trips in the summer and overheating of tires are an extra and important reason to double-check tire pressure.
