Why Does Tire Pressure Increase?

[VonLola]

Tire pressure increases primarily due to temperature effects causing thermal expansion and contraction of gases. Friction between the tire and the road surface, as well as among various tire components, generates heat, leading to higher internal tire pressure, which is a normal phenomenon. Below is relevant information about tire pressure: Tire pressure requires regular maintenance: Tire pressure is significantly influenced by seasonal factors. In summer, high temperatures cause tires to heat up during driving, and excessive pressure can lead to blowouts, so tire pressure should be slightly lower. In winter, tire pressure should be slightly higher than in summer due to thermal contraction and expansion. Generally, a car's tire pressure can be increased by 0.1-0.2 bar in winter. Effects of improper tire pressure: Incorrect tire pressure reduces friction and adhesion, affecting braking performance and ride comfort. It also accelerates uneven wear on the central tread pattern, shortening the tire's lifespan.

[LaPhoebe]

I specifically checked the tire pressure when washing my car the other day, but after sitting in the sun all afternoon, the pressure shot up. The reason is simple—air expands when heated. In summer, parking in an open lot for two hours can increase tire pressure by 0.3 bar. It was even more noticeable on the highway last time; after just an hour of driving, the tire pressure monitoring alarm started beeping. The most frustrating part is when the cold tire pressure in the morning is normal, but by noon, the sun causes it to exceed the limit. A mechanic advised me to keep summer tire pressure 0.1-0.2 bar below the standard to allow for expansion, but never release air yourself—it’s best to have it adjusted professionally with a temperature-compensated tire pressure gauge.

[TylerLynn]

Over the years in auto repair, I've seen many cases of abnormal tire pressure, with overinflation being the most common. Many car owners find frequent inflation troublesome and directly pump their tires to 0.5bar above the standard value, resulting in the middle of the tread wearing flat. Last week, there was an even more outrageous case with a modified car—21-inch low-profile tires inflated to 3.0bar when the manufacturer's recommendation was only 2.3bar. High tire pressure not only makes the ride bumpy but also caused the rims to deform when going over speed bumps. A reminder to everyone: don't exceed the upper limit of tire pressure, especially if you've switched to non-OEM specification tires. It's best to consult a professional organization to recalculate the appropriate tire pressure.

[MacFinn]

Long-haul drivers are well aware of the patterns in tire pressure changes. At 6 AM when the temperature is 18°C, the tire pressure is 2.5 bar, but by noon when the road temperature hits 50°C, the pressure can shoot up to 2.9 bar. Once, when I was rushing to deliver seafood, overloaded by half a ton and driving in 38°C heat, the tire pressure alarm was blaring like an ambulance. The lesson learned is to always carry an electric air pump, release excess pressure during rest stops, let the tires cool for half an hour, and then adjust back to around 2.6 bar. Metal rims dissipate heat slowly, so tire pressure takes much longer to drop than you might think.