
Spare tires are categorized into full-size spare tires and compact spare tires. For compact spare tires, the total mileage should not exceed 50 kilometers. Full-size spare tires are identical in size to regular tires and have no mileage restrictions, but they must be driven at lower speeds. Full-size spare tires have the exact same specifications as the other four tires on the vehicle and can replace any temporarily or permanently unusable tire. Compact spare tires have slightly smaller diameters and widths compared to the other four tires and are only intended for temporary use. They should only be used on non-driving wheels, and the maximum speed should not exceed 80 kilometers per hour.

I just changed a spare tire recently, and I know exactly how it feels. A spare tire is just for emergencies, whether it's full-size or compact, and it's recommended not to exceed 80 km/h. After I replaced the spare on my SUV, the mechanic pointed out that the tread was worn, reducing grip, especially in rainy conditions when it's prone to slipping. Don't speed—my dashboard alarms if I go over 80. Once, I saw someone driving 120 km/h on a spare tire on the highway, and it really made me nervous. Spare tires also have a shelf life—when I lifted the trunk floor, I found my spare had aged after seven years from manufacture, covered in fine cracks. Oh, and if you've patched a tire, get it replaced ASAP. My colleague drove 300 km on a patched tire, and the sidewall ended up bulging. The first thing after changing to a spare is to head to the nearest repair shop—don't push your luck.

Last month I had a flat tire in the suburbs and used the spare tire. First-hand experience confirms that compact temporary spares are extremely difficult to drive with. These emergency tires can barely manage 50km at most, with a design speed limit of 80km/h. The car's system immediately popped up warnings, and the steering felt dangerously loose - my heart was in my mouth during turns. The mechanic said these spares are 30% narrower than regular tires, causing uneven force distribution that damages the suspension. Later I checked the manual and discovered spare tires require 9.0bar pressure, nearly double normal tires. The worst part? Some modern cars don't even include physical spares - my neighbor's EV just came with tire sealant, that sticky stuff is completely useless for sidewall damage. For frequent long-distance drivers, I recommend keeping an air compressor in the trunk. Once I slowly leaked air from a nail puncture and used the compressor to reach the repair shop - much easier than changing to a spare tire.

The limits of a spare tire depend on its type. A full-size spare can theoretically be used normally, but I've seen five-year-old spares with oxidized rims—using such tires for long trips is practically suicidal. Compact spares are even riskier, with sidewalls as thin as paper. My mother-in-law's car came with one, and the manual explicitly states a 200 km limit. The key factors are speed and road conditions—slow city driving buys more time, but continuous highway use risks overheating and blowouts. During my last maintenance check, the mechanic measured my spare's tread depth at just 1.6mm with calipers, warning it couldn't handle rainy conditions. Modern cars' tire repair kits are actually more reliable than spares—automatic inflation + sealant gets the job done in five minutes without dirtying the trunk with tire changes.

Having handled over a thousand vehicle cases, spare tire issues need to be addressed at three levels. First, material lifespan: rubber deteriorates automatically after six years of inactivity, and a spare tire with sidewall cracks is dangerous even for 50 kilometers. Second, type differences: a full-size spare can run 500 kilometers without issue, but a compact spare is like putting small shoes on your car—forcing 100 kilometers may damage the axle. Most critically, tire pressure: last week, an owner didn’t know the spare required 4.2 bar pressure, resulting in a ruined tire after just 10 kilometers of low-pressure driving. Also, watch the wheel size—a friend borrowed a car with a 17-inch spare on 19-inch wheels, triggering ABS errors. After installing a spare, immediately disable ESP and cruise control, then navigate to the nearest tire shop. Don’t trust distant 'authorized repair points' listed 30 kilometers away.


