Why Does It Still Show Low Tire Pressure After Changing to the Spare Tire?
2 Answers
After changing to the spare tire, the reason it still shows low tire pressure is that the spare tire itself has insufficient air pressure. Tire pressure refers to the air pressure inside the tire. Air pressure is crucial for tires, as both overinflation and underinflation can shorten the tire's lifespan. Below are potential issues caused by improper tire pressure: 1. Overinflation: Excessive air pressure can overstretch the tire cords, reducing the elasticity of the tire body and increasing the load on the car while driving. This may lead to internal cracks or blowouts upon impact. Overinflation also accelerates tread wear and reduces puncture resistance. 2. Underinflation: Low air pressure increases tire body deformation, making the sidewalls prone to cracks and causing excessive flexing. This generates excessive heat, promoting rubber aging, fatigue in the cord layers, and cord breakage. It also increases the tire's contact area with the ground, accelerating shoulder wear.
Last time after I changed to the spare tire, the warning light was still on, which puzzled me. The spare tire is usually a temporary donut tire with higher pressure settings than normal tires, typically designed to be inflated to around 60 psi, while normal tires might be 32-35 psi. However, after prolonged storage, it may leak to below 50 psi, and the dashboard showing low pressure is actually reminding you to check the actual value. Another key point is that the Tire Pressure Monitoring System (TPMS) wasn't reset. The sensors might not have automatically connected to the new wheel during the replacement, so you need to actively go to the car's menu or button to learn the new position. Every time, I first manually check the spare tire with a reliable pressure gauge. If the reading is normal, I then refer to the owner's manual to reset the TPMS to avoid false alarms that could distract me while driving. Remember, spare tires are only for low-speed, short-distance use. Drive to the repair shop to check the entire system for safety.
