How much air should be added to the spare tire?
2 Answers
Spare tires should be inflated to 2.5 bar. Since spare tires are not frequently used, it's best to maintain a higher air pressure to prevent them from losing their emergency function due to insufficient pressure when needed. Effects of low tire pressure: Low tire pressure increases tire body deformation, making the sidewalls prone to cracking while generating flexing movements that lead to excessive heat buildup. This accelerates rubber aging, causes fatigue in the cord ply, and may break the cords. It also increases the tire's contact area with the ground, accelerating shoulder wear. Effects of high tire pressure: Excessive tire pressure overextends and deforms the tire cords, reducing the tire body's elasticity. This increases the load on the vehicle during driving, and impacts may cause internal cracks or blowouts. High pressure also accelerates tread wear and reduces puncture resistance.
Last time I changed to the spare tire, I almost got into trouble because the tire pressure was insufficient. That compact spare tire may look small, but it needs to be fully inflated to be effective. Typically, its pressure requirement is much higher than regular tires, usually around 60 psi (approximately 4.1 bar). The exact specification is printed either in your vehicle's manual or on the small label near the driver's side door frame—never guess the pressure. I remember I casually inflated mine to 40 psi that time, which resulted in a bumpy ride and accelerated tire wear. Luckily, I noticed it early. Since spare tires stored in the trunk gradually lose air over time, it's recommended to check the pressure every three months using a standard tire pressure gauge. When temporarily using a spare tire, never drive too fast—keep it under 80 km/h—and avoid long-distance travel for safety. The proper course of action is to visit a repair shop as soon as possible to switch back to a regular tire.
