What to Keep in Your Car When a Tire Fails

What you need in your car for a flat tire

A spare tire, jack, and lug wrench are the three things that let you change a tire yourself on the roadside. Most cars come with at least a compact spare (sometimes called a "donut"), a scissor jack, and a wrench built into the trunk or under the floor mat. Check your owner's manual to find where yours are stored — they are often in places you would not think to look.

If your car did not come with these items, or if you have lost them, you can buy them separately at auto parts stores. A full-size spare costs more than a compact spare but lasts longer and handles better at highway speeds. A compact spare is lighter, takes up less room, and costs less, but you should not drive more than 70 miles on one or go faster than 50 miles per hour.

Beyond the basic three, a few other items make the job safer and easier: a flashlight or headlamp (so you can see what you are doing if it is dark), work gloves (to keep your hands clean and protect them from sharp edges), and a tire pressure gauge (to check that your spare has enough air). Wheel wedges or heavy rocks also help keep your car from rolling while you work.

Key Takeaways

• Your car should have a spare tire, jack, and lug wrench; check your owner's manual to find where they are stored.
• A compact spare is lighter and cheaper but should only be driven up to 70 miles at speeds under 50 mph.
• A full-size spare costs more but can be driven like a regular tire until you reach a repair shop.
• A flashlight, work gloves, and tire pressure gauge make changing a tire safer and less messy.
• Keep your spare tire inflated to the pressure listed on your driver's door jamb, not the pressure on the tire itself.

Checking that your spare is ready to use

A spare tire that is flat or nearly flat will not help you. Every month or two, use a tire pressure gauge to check the air pressure in your spare. The correct pressure is printed on a sticker inside your driver's door jamb — it is usually different from the pressure printed on the tire itself. If your spare is low, add air at a gas station or tire shop.

Also look at the spare itself for cracks, bulges, or dry rot (a grainy, cracked appearance on the rubber). If you see any of these, the tire is unsafe and should be replaced before you need it. A spare that has been in your trunk for years may have dry rot even if it looks mostly normal, so inspect it closely.

The difference between a compact spare and a full-size spare

A compact spare (or "donut") is smaller and lighter than a regular tire. It takes up less space in your trunk and weighs less, which is why most manufacturers include one. The trade-off is that it is not meant for long-term use. You should not drive more than 70 miles on a compact spare, and you should stay under 50 miles per hour. If you get a flat far from a repair shop, a compact spare gets you to one safely, but you cannot use it as a permanent replacement.

A full-size spare is the same size as your other tires and can be driven like any other tire. It costs more and takes up more trunk space, but if you get a flat, you can drive to a shop at normal speeds without worrying about distance limits. Some people keep a full-size spare in their trunk instead of a compact one for this reason. If you buy a full-size spare, make sure it matches the size and load rating of your other tires — your owner's manual lists the correct size.

What to do if your spare is flat or missing

If you discover your spare is flat when you need it, or if it is missing from your car, you have a few options. You can call a towing service to take your car to a repair shop. You can also call a roadside assistance program like AAA if you are a member. Many car insurance policies include roadside assistance, so check your policy before you pay out of pocket.

If you are on a highway or in an unsafe location, do not attempt to change a tire yourself. Turn on your hazard lights, move as far from traffic as you can, and call for help. If you are in a safe spot and want to change the tire yourself but have no spare, some tire shops will deliver a spare to your location, though this usually costs more than having your car towed.

Tools and supplies beyond the basic three

The jack and lug wrench that come with your car are usually enough to change a tire, but a few additions make the job easier and safer. A flashlight or headlamp is essential if you are changing a tire in the dark — you need to see what you are doing. A battery-powered headlamp leaves both hands free. Work gloves protect your hands from dirt, sharp metal edges, and hot brake components. Wheel wedges or heavy rocks placed behind the wheels opposite the flat tire keep your car from rolling while you work.

A tire pressure gauge lets you check that your spare has enough air before you need it. A tire plug kit or tire patch kit can temporarily seal a small puncture in the tread, though this is not a permanent fix and you should still drive to a shop to have the tire properly repaired. A breaker bar (a longer wrench) makes it easier to loosen lug nuts that are very tight. Keep these items in a small bag or box in your trunk so they stay together.

Where to buy a spare tire and tools

Auto parts stores like AutoZone, O'Reilly, Advance Auto Parts, and NAPA carry spare tires, jacks, lug wrenches, and all the tools mentioned above. Tire shops like Discount Tire, Firestone, and Goodyear also sell spares and can install them if you want. Big-box retailers like Walmart and Costco carry some of these items at lower prices, though selection varies by location.

When you buy a spare tire, bring your car's year, make, and model, or take a photo of the tire size from your driver's door jamb. The person at the store can then tell you which spares fit your car. If you are not sure what size to buy, your owner's manual lists the correct spare tire size. Prices for compact spares usually range from $50 to $150, while full-size spares typically cost $100 to $300 or more, depending on the brand and tire quality.

Storing your spare tire safely

Most cars have a designated space for the spare — under the trunk floor, mounted on the back of the car, or in a wheel well. Keep your spare in this space so it is protected from weather and does not roll around while you drive. If you buy a full-size spare and your car does not have room for it in the trunk, you can store it in a garage at home and keep a compact spare in your car for emergencies.

Check your spare every few months to make sure it is still there and still has air pressure. Spares stored in trunks can lose air over time, especially in hot weather. If you live in a very hot climate, your spare may lose pressure faster, so check it more often. A spare that is properly stored and maintained will be ready when you need it.

Frequently Asked Questions

Can I drive on a compact spare tire for a long distance?

No. A compact spare is designed only for short trips to a repair shop. Driving more than 70 miles or faster than 50 mph on a compact spare can damage it and make your car harder to control. If you are far from a shop, call a towing service instead of driving on the spare.

How often should I check my spare tire's air pressure?

Check your spare every month or two using a tire pressure gauge. The correct pressure is on the sticker inside your driver's door jamb. Spares lose air over time, especially in hot weather, so regular checks keep it ready when you need it.

What if my car did not come with a spare tire?

Some newer cars come with tire repair kits instead of spares. If your car has neither, you can buy a compact or full-size spare at an auto parts store or tire shop. Bring your car's year, make, and model so the store can sell you the correct size.

Is a full-size spare worth the extra cost and trunk space?

A full-size spare costs more and takes up more room, but you can drive it at normal speeds without distance limits. If you often drive far from repair shops or want peace of mind, a full-size spare may be worth it. If you mostly drive in the city, a compact spare is usually enough.

What should I do if my spare tire has dry rot?

Dry rot means the rubber is cracking and breaking down, making the tire unsafe. Replace it before you need it. A spare with dry rot can fail suddenly, leaving you stranded. Check your spare every few months for cracks, bulges, or a grainy appearance.