Spare Tire Talk: Answers to FAQs About Spare Tires

You may have noticed that many new cars are coming without the spare tire that’s traditionally housed in the back of the trunk. While this is a small contribution to the ultimate decision of whether or not to buy a car, it’s worth knowing what you’ll be missing out on. For those of us with spare tires stored in our cars, this article will serve as a refresher for spare tire purpose, use, and maintenance.

What Is a Spare Tire?

It is an extra tire that you store in your car in case of an emergency like experiencing a blowout or puncture while on the road. Rather than have your vehicle towed, you can quickly switch out your damaged tire with your spare and get back on the road. 

Traditionally comes in a compact, lightweight model meant to get you that extra few miles in case one of your tires blows out. These are referred to as “donut spares.” It’s compact and stored in your trunk while not weighing your car down. However, due to its small size, it’s usually only rated for around 50 miles per hour and only 50-60 miles. It’s a temporary, quick fix.

Full-size spares are an option, but you’ll need to have the space on your vehicle for a whole extra tire. Many Jeeps have full-sized spares mounted on the door to the trunk, for example. 

Are Spare Tires Universal?

Spare tires are not universal. The spare tire just has to fit that wheel, meaning it must be compatible with the specific size and type of wheel on your vehicle. Matching full-sized tires are the closest option to a universal spare tire, but even these can vary. A donut or temporary spare will maximize the vehicle's trunk space while providing a solution in case of a flat, but it's crucial to check if it fits your car model.

How Long Does a Spare Tire Last in Your Trunk?

We are often asked how long a spare tire will last, how long you can drive on a spare tire and what the speed limit is for a replacement tire. The industry standard is you drive no more than 50 miles and no faster than 50 miles per hour on a spare tire.

A donut tire, also known as a compact spare tire, is smaller, lighter, and designed for temporary use, typically allowing for speeds up to 50 miles per hour and a limited distance of 50-60 miles, whereas a regular tire is full-sized, durable, and intended for normal, long-term driving conditions.

A donut spare can last around 6-10 years in storage. How long an unused spare tire lasts depends on how well you care for it, just like your everyday tires. A spare tire should be checked when you would check your normal tires for wear, pressure, and other damage. Even in storage, the tire rubber can decay over time, rendering the tire too brittle to use. 

Do You Need to Check Tire Pressure in Your Spare?

Yes, you’ll need to make sure your spare tire is at the correct pressure, but also check for punctures or cracks from extended storage. Keep in mind that the donut spare needs much higher air pressure than your normal tires – spare tire PSI will be indicated on the sidewall. 

Is a Spare Tire the Same Size as Regular Tires?

A full-sized spare should be the exact size as your normal tires and can even be used in your normal tire rotation schedule. However, a donut spare will be much slimmer than your normal tires for easier storage. This doesn’t mean that you can use just any donut spare, though. This more compact tire will still need to be designed for the correct specification and size of your vehicle. If your car does not come with a donut spare, you’ll need to consult a tire specialist on purchasing one that will work with your vehicle. 

What Is a Self-Sealing Tire?

A self-sealing tire is coated inside with a sealant. When your tire experiences a puncture from a nail or other sharp object, the sealer inside is designed to surround and fill in the hole to stop a loss in tire pressure. This allows you to keep driving and head to a repair shop without needing to stop. Self-sealing tires have a limited puncture size they’ll be able to handle and won’t work on punctures into the side of the tire. They can also be expensive and difficult to repair.

Continental ContiSport Contact 5 with ContiSeal is an example of a self-sealing tire.

What Is a Run Flat? 

A run-flat tire is designed to maintain safety and steering in the event of a tire blowout. They achieve this by having a strong, reinforced sidewall and internal support ring that will still be able to handle around the same distance and speed as a donut spare when damaged. Keep in mind that in the event of a loss in tire pressure, driving a run-flat for even a small distance can completely ruin the tire. This means you’ll have to replace, rather than patch, the tire. They also can be expensive and uncomfortable to drive with. Learn more about run-flat tires.

Why Are Some Spares Called Space-Saver Tires?

A space saver tire is another term referring to the smaller, slim donut tire. They have limited range and speed, usually only around 50 miles at 50 miles per hour, but are much cheaper and easier to store than some other options. You do, however, need to know how to change a tire.

What Is a Folding Tire?

A folding tire is the ultimate space-efficient tire. This tire will be deflated in the back of your vehicle until it’s needed. It will require a bit more setup, and you’ll need a tire pump, but there’s no other spare tire out there that will take up less space. These are also usually rated for even lower mileage and ranges than donut spares.

Are Wheels For Spare Tires the Same as Ground Tires?

If you have a full-size matching spare tire, the tire should be the same size and dimensions as the other tires on your car. However, many types of spares will have lighter or slimmer wheels to save space in storage. 

Full-sized, for example, will have entirely different wheels than your other tires. They’ll have the same height as your other tires, but will have much less width for easier storage. This will mean less traction on the road compared to your other tires. 

Donut tires will be uniquely made for your specific vehicle, and will not have the same wheels at all. Because of the size difference between donut and regular tires, you won’t be able to drive very fast. 

There’s not much standardization when it comes to tires and spares are no exception. You won’t be able to easily swap out spare tires between cars. All the more reason to make sure you have a spare tire in the back of your car for the worst-case scenario.

What Kind of Spare Do You Need?

The type of spare depends much on your skill set, vehicle, and driving patterns. Spare tires are not universal; your spare should match the size of your regular (ground) tires. 

If you have a larger vehicle with extra storage space, you can get a full-sized spare that you can work into your regular tire rotation to extend the tread life of all tires.

If you have a smaller car and are on a budget, a donut spare is probably the best option for you.

If you’re uncomfortable with changing a tire, or often drive in situations where you can’t easily stop and change a tire, a run-flat tire could be the perfect option.

Take stock of what your specific needs are and how much you’re willing to spend preparing for emergencies.

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