Rick's Free Auto Repair Advice

How long can you drive on a spare tire?

Quickly replace a donut spare tire

What is a space saver spare tire?

In an effort to cut manufacturing costs and reduce vehicle weight and save space, car makers switched from a full size spare tire to a smaller “limited use,” “space-saver,” “donut,” or “compact spare tire.” These smaller tires typically weight about 10-15-lbs less than a full size replacement spare. They’re designed to get you back on the road and to a repair shop so you can replace or repair the flat tire. That’s it!. They’re NOT designed for long term use.

What’s different about a space saver spare tire?

In most cases, a temporary compact spare tire is smaller than the rest of the tires on the vehicle. That’s done to save weight and space. The spare tire’s sidewalls aren’t as beefy as a traditional tire in order to save weight. To compensate for using less rubber on the tire’s shoulder and sidewall, the tires must be run at a much higher inflation pressure, either 60-psi or even 80-psi.

Donut spare tires also have far less tread depth in order to save weight. They don’t need full 11/32-in tread depth because they’re only designed to run for 50 to 70-miles, just long enough to get you to a repair facility.

spare tire

Differences between a full size tire and space saver donut spare tire

Because these spare tires have far less tread depth and width, they have far less traction and stopping power, so they must be driven at a maximum speed of 50-MPH. Drive even slower on wet, snow or ice. The shallow tread depth simply can’t provide the same traction in snow as a regular tire and can’t move water off the road as quickly as a regular tire. As a result, you’re far more likely to hydroplane in wet roads with a compact spare tire.

Compact tires also have a smaller circumference compared to your regular tires. That’s another reason why they’re limited to a maximum driving distance of 50 to 70 miles, especially if they’re mounted on a drive wheel. Driving beyond that limit with the spare on a driven wheel can cause substantial and costly damage to your final drive (differential).

How to care for a spare tire?

Spare tires lose air pressure like every other tire on your vehicle. Since they need 60 to 80-psi to operate, chances are the tire inflatorspare will be low on air when you need it most. Rather than constantly refill the spare tire, your best bet is to carry an inexpensive tire inflator and pump it up to recommended pressure when you need it.

How to mount a compact spare tire

If your vehicle has alloy wheels, chances are your spare tire came with different lug nuts designed for steel wheels. If so, it’s critical that you use the lug nuts that came with the spare and not the lug nuts from your alloy wheels. Using the wrong lug nuts on a steel wheel can cause the wheel to come off during use and result in serious injury or death.

spare tire lug nuts

Using the wrong lug nuts can cause the wheel to come off and cause serious injury or death

How long does a space saver spare tire last?

Donut spares are designed to last 7 to 10 years if stored according to the tire makers recommendations. Exposure to sunlight and high heat reduces the tire’s life.

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat


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