You have probably heard more than once that tire pressure is somehow dependent on the outside temperature. In fact, the temperature has a lot to do with the entire operation of the vehicle, and not just with the tires. You probably remember how long it takes to warm up your car in the winter until the whole system can function properly. Not to mention that the TPMS sensors indicate pressure deviations when you actually have just adjusted the tire pressure.
Well, the temperature really plays tricks on our vehicle. And I'm here to explain how the Celsius degrees impact our tires. Believe me, once you understand the principle of operation, it will be much easier for you to understand your car.
The WHYs behind the temperature and tire connection
Let's better understand how temperature affects the tires. The explanation can be found in the physics lesson that you probably missed when you were in college. You probably thought that physics lessons would not help you in life. But now the moment has come those lessons indeed have value.
So why does temperature matter to your tires? Let us remember that gases have the physical property of contracting and expanding depending on the temperature around them. This means that as the temperature rises, the air particles in the tires detach from each other, expanding the coverage area. As a result, they take up more volume. The same is true for the opposite scenario - the air particles contract, attaching to each other and covering less space. Thus, the air in the tires is reduced.
Let's exemplify this idea. Imagine a large room with many people in it. If it's cold in the room, people will try to hug each other to warm up. So everyone will gather in a corner while the space of the room will remain partially empty. If the temperature starts to increase, people will try to separate themselves from each other. They will prefer to sit further from each other to have enough air and somehow be cooler. Respectively, they will spread over the entire surface of the room. Starting from this premise, it becomes clear what physical process takes place in the tires during a cold day and a warm day. The TPMS sensors do nothing else than react in a panic to the changes inside the tires.
Does this mean temperature only affects tire pressure?
Many of us think that tire pressure is the only effect that temperature generates. Tire pressure is indeed the most impacted, but it is certainly not the only aspect impacted by temperature. In this context, remember how tires don't perform well when they are not intended for the right season.
For example, if you have winter tires in the warm season, you will suddenly feel how the car performs poorly as it undergoes traction issues. This effect does not only occur due to inappropriate treads but also due to the inappropriate temperature. Tire manufacturers take into account the temperatures for which they are intended. Respectively, they add components and structures to deal with the temperatures for which they are designed. If the tires are used in other environments, they can expand or contract at the structural level, leading to improper traction.
For this reason, one of the most suitable types of tires for areas with fluctuating temperatures is all-season tires. As long as they are not exposed to extreme temperatures, they perfectly cope with temperature fluctuations without severely affecting their structure.
In conclusion, the temperature impacts not only the pressure inside the tire but also its performance. It is true that it is not a direct impact, but rather a secondary one. However, the most correct thing is to follow the manufacturers' recommendations regarding the type of tires we wear, so that they coincide with the temperatures for which they were designed.
How much does temperature affect tire pressure?
You have to take into account the fact that the pressure can decrease or increase due to other factors, not only the temperature. For this reason, it is difficult to estimate exactly how much the pressure will suffer as a result of temperature changes. Experts have concluded that the pressure changes by 1-2 PSI with the increase or decrease in temperature by 10 degrees Fahrenheit. These indexes can vary if there are complementary reasons that influence tire pressure.
How do my tires lose pressure in winter?
As you already know, various criteria influence tire pressure, not just temperature. So the pressure fluctuations in winter can only be estimated, not at all confirmed.
Let's take an example. Let's say you adjusted the tire pressure up to 32 PSI at a temperature of about 30 degrees Celsius on a summer day. If you maintain this standard until winter, when the temperature reaches about one degree Celsius, you will reach a pressure of about 23-25 PSI. That would be a bit low for your vehicle, so you should adjust the pressure again to the limit recommended by the manufacturer.
Does this mean that you have to over-inflate the tires in cold weather?
As you saw in the previous example, the pressure will drop in the tires once the temperature also drops. With this in mind, adjusting the pressure is a must. As for over-inflating, of course, you have to put more pressure to compensate for the loss due to the temperature change. But you have to be very careful with the meaning of "over-inflating". Manufacturers usually propose recommendations regarding the pressure limit during the winter. They suggest that adding no more than 3-5 PSI in cold weather is more than enough. This reserve would be enough for a fluctuation of around 10 degrees Celsius. However, you would do your vehicle a favor if you followed the recommendations of your manufacturer because each of them comes with a specific set of specifications for each set of tires.
Another important aspect is not to make these pressure fluctuations suddenly. Try to feel your car and understand the way it behaves with temperature changes. Sometimes, adding only 1-2 PSI is more than enough to cope with the changes in degrees.
How does pressure change with increasing temperature?
You already know that as the temperature increases, the pressure in the tires will also get higher. But to what limit does it increase with the transition from cold to warm? In fact, the rule in cold temperatures does not differ much from that in high temperatures. Tire pressure tends to increase by about 1-2 PSI for every 10 degrees Fahrenheit.
This means that if you have about 32 PSi in your tires on 1° Celsius cold days, these will become 37-42 PSI at 30° degrees Celsius. The calculations are approximate, of course, but this is how the changes take place more or less.
Why do manufacturers indicate the maximum PSI on tires?
Many drivers wonder if it is necessary to inflate the tires to the limit that the manufacturers indicate on the tire sidewall. My answer, and that of many experts, is no, it is not suitable for optimal tire pressure. The pressure that the manufacturers indicate on the tire sidewalls tells you about the limit that you should never cross. Otherwise, you risk running into catastrophic outcomes.
Instead, what you need is to find the information on the doorjamb of your vehicle. This information contains the RECOMMENDED pressure, which is usually different from the maximum one. With the recommended pressure, you have more stable safety on the road, regardless of the outside temperature.
Your tires need regular inspection, especially with temperature changes
I think it is unnecessary to reiterate that the pressure in your tires is not constant at all. Many factors influence it and temperature changes are just one of them. For this reason, it is not difficult for me to repeat for the 10th time that you must check the tire pressure once a month or when necessary (but not less often than once a month). The consequences of improper tire pressure are far too risky for the vehicle and the driver's safety.