
The normal tire pressure for a spare tire is between 2.2 and 2.5 bar, and it may vary depending on the brand and model of the vehicle. Strictly speaking, tire pressure refers to the air pressure inside the tire. There is a standard tire pressure chart printed on the rear end of the driver's side door, which indicates the pressure when the tire is cold. A tire is a circular elastic rubber product mounted on various vehicles or machinery to roll on the ground. Tires are often used under complex and demanding conditions, enduring various deformations, loads, forces, and high and low temperatures during operation. Therefore, they must have high load-bearing capacity, traction performance, and cushioning performance. A spare tire is a backup tire prepared for a car. In case of a flat tire or any issue with a wheel, the spare tire can promptly replace it, preventing the car from breaking down midway.

The tire pressure for a spare tire depends on its specific type. For regular family cars equipped with a full-size spare tire, the pressure is usually the same as the normal tires, around 2.3-2.5 bar, which is clearly indicated on the door frame label. However, compact temporary spare tires are different—many small cars I've seen require these to be inflated to 4.2-4.8 bar, nearly double the pressure of regular tires. This high pressure is mainly because temporary tires are smaller in size and need more air to support the vehicle's weight. Last time I helped my neighbor check his spare tire, his SUV's temporary tire was labeled at 60 psi, equivalent to about 4.1 bar. Regardless of the type, spare tires tend to lose air over time, so it's advisable to check the pressure every quarter or before long trips to avoid issues when you need it most. Remember, after installing a spare tire, don't exceed 80 km/h—it's not meant for long-term use.

The tire pressure of a spare tire depends on the situation. If you have a full-size spare tire in the trunk, the required pressure is generally the same as that of the regular wheels. For sedans, it's typically around 2.4 bar, but you should check the sticker on the door for specifics. Nowadays, many cars come with a compact folding spare tire, which requires higher pressure, usually between 60-70 psi (equivalent to 4.1-4.8 bar), because such a small tire has to bear the weight of the entire vehicle. During routine car maintenance, I always remind fellow drivers to check the condition of their spare tires, especially the compact ones with plastic wheel covers, as they are most prone to slow leaks. Never use a spare tire for an extended period—its sidewalls are very thin, and exceeding 80 km/h can be dangerous. Use it only for emergencies, covering a few dozen kilometers at most, and then promptly switch back to a proper tire.

The spare tire pressure is usually higher than that of regular tires. For a compact emergency spare, it should be inflated to approximately 4.2-4.8 bar to meet the standard. This high-pressure design is necessary because the smaller spare tire cannot support the vehicle's weight without sufficient air pressure. Full-size spare tires, however, maintain the same pressure as regular tires, typically within the 2.3-2.5 bar range. Checking your vehicle's standard is simple: lift the trunk mat to see the markings on the spare tire's sidewall or refer to the owner's manual. Once before a road trip, I checked my spare and found it was only at 1.8 bar—fortunately, I inflated it to the specified value in advance, and it came in handy on the road. Remember, spare tires are for emergency use only and should not exceed 100 kilometers or speeds of 80 km/h.

Spare tire pressure depends on the type. For full-size spare tires, follow the vehicle's standard pressure, usually between 2.2-2.6 bar. Compact temporary spares are special, typically requiring at least 60 psi (~4.1 bar), with some brands specifying up to 70 psi. Many drivers don't realize spare tires need separate pressure checks. The yellow label on the tire sidewall shows the exact value - some indicate standards like 420 kPa. Use a digital gauge to check monthly; if pressure drops 20% below specification, refill immediately. Rubber naturally loses air - a spare left unused for six months may go flat.


