Why Does Car Tire Pressure Decrease?
3 Answers
The gradual decrease in tire pressure may be caused by a leaking valve stem, or it could be due to wheel rim deformation, which prevents a tight seal between the rim and the tire, leading to slow air leakage during use. Hazards of Overinflated Tires: Reduced tire friction and adhesion, affecting braking performance; causes steering wheel vibration and misalignment, reducing driving comfort; accelerates wear on the central tread pattern, shortening tire lifespan; increases vehicle vibration, indirectly affecting the lifespan of other components; overextends tire cords, reducing elasticity and increasing the load on the vehicle during driving; decreases puncture resistance. When encountering sharp objects like nails or glass on the road, the tire is more prone to punctures, leading to internal cracks or blowouts. Hazards of Underinflated Tires: Increases friction with the road surface, raising fuel consumption; makes the steering wheel heavy and prone to misalignment, compromising driving safety; increases movement in various parts of the tire, causing abnormal heat due to excessive rolling; reduces the functionality of cords and rubber, leading to delamination or cord breakage, and excessive friction with the rim, damaging the bead area and causing abnormal wear; multiplies friction with the ground, rapidly increasing tire temperature, softening the tire, and drastically reducing strength. High-speed driving may result in blowouts; increases tire deformation, making the sidewalls prone to cracks and causing flexing, leading to excessive heat, rubber aging, cord fatigue, and breakage, while also increasing the tire's contact area with the ground, accelerating shoulder wear.
Having driven for decades, low tire pressure is all too common. As tire rubber naturally ages, it loosens, allowing air to slowly seep out; in cold weather, tire pressure drops noticeably faster. Sometimes, a small nail puncture or tiny hole on the road can lead to a complete loss of air. I've even experienced air leakage due to an improperly tightened valve cap after long, bumpy trips. Over time, wheel rims may deform and fail to seal properly, especially if frequently driven on rough roads. Remember to check with a tire pressure gauge monthly, maintaining the manufacturer's recommended level—don’t wait until safety is compromised.
Before every long trip, I always check the tire pressure and often find it alarmingly low. The primary reason is that air gradually seeps through the tire walls—from a physics perspective, rubber materials have microscopic pores. Temperature fluctuations also play a role; for example, in summer, heat causes tire pressure to rise, making it seem normal after driving for a while. But when autumn suddenly brings colder weather, contraction leads to a sharp drop in pressure. Damaged valve cores or poor wheel rim seals are also common issues in older cars. These problems not only affect driving stability but also increase fuel consumption. I’ve made it a habit to use a spare tire pressure gauge for quick checks and timely inflation to ensure safe driving.
