Nobody wants to deal with a flat tire, especially when you’re already running late or stuck somewhere unfamiliar. But flats happen, and when they do, most drivers just throw on the spare and start driving without really thinking about whether that’s actually safe or how long they can keep doing it.

So let’s talk about what you actually need to know about spare tires, because there’s more to it than most people realize.

First Things First What Do You Do When You Get a Flat?

The moment you feel that familiar thud and pull, your first move should be getting off the road safely. Turn on your hazard lights immediately. If you’re on a highway, don’t stop on the narrow shoulder if you can avoid it get to an exit or a wider space first. Your safety matters more than your tire.

Once you’re parked somewhere safe, that’s when you deal with the tire. And here’s something a lot of drivers ignore  driving even a short distance on a completely flat tire can wreck your wheel rim. What starts as a $150 tire replacement can turn into a $500 repair if you push it. Get off the road, but do it smart.

Not All Spare Tires Are the Same

This is where most people get confused. They assume a spare is a spare. It isn’t.

The small, narrow tire you’ll find in most car trunks is called a compact spare or donut tire. It’s designed to be lightweight and easy to store. These tires run at around 60 PSI, which is much higher than a regular tire, and they’re genuinely not built to handle highway speeds or long distances. They’re a stopgap  just enough to get you somewhere you can get a real tire fitted.

Larger vehicles like SUVs and pickup trucks often carry a full-size spare. These look and feel much closer to your regular tires, and they give you a bit more flexibility. But even then, they’re not always from the same manufacturer as your other tires, and the tread or construction might be slightly different. You still shouldn’t treat one as a permanent solution.

Then there are run-flat tires, which some newer vehicles come with instead of a spare. These have reinforced sidewalls that let the tire keep its shape even after losing pressure. They’ll get you to a garage, but they have their own distance and speed limits just like any spare.

So How Fast Can You Actually Go?

If you’re on a donut spare, keep it under 50 mph. That’s not a suggestion it’s the limit these tires are built for. Most spare tires have the speed rating printed right on the sidewall if you want to double-check yours.

Driving at 70 mph on a spare that’s rated for 50 isn’t just hard on the tire  it’s genuinely dangerous. These tires are smaller, thinner, and not designed for that kind of stress. The risk of a blowout goes up significantly when you push past the rated speed.

How Far Can You Go Before You Need a Proper Tire?

The general rule most mechanics and manufacturers go by is 50 to 70 miles maximum on a spare. For a donut spare, you really want to stay on the lower end of that range. These tires wear quickly because they’re so much smaller than the other three on your car, and the uneven sizing puts extra strain on your drivetrain and brakes.

A full-size spare gives you a little more room to breathe, but the same thinking applies. Get to a tire shop as soon as you reasonably can. Don’t plan a three-hour road trip on a spare and assume everything will be fine.

A Few Things to Watch Out For While You’re on a Spare

Your car will handle differently on a spare that’s just reality. The braking distance increases, and if your vehicle has an anti-lock braking system, the warning light might come on. Leave more space between yourself and the car ahead. Don’t tailgate, and brake earlier than you normally would.

In wet or slippery conditions, be extra careful. Spare tires have very little tread, which means far less grip than a regular tire. Slow down on wet roads and take corners gently. This isn’t the time to test your car’s handling.

Before you drive anywhere on the spare, check the inflation. A lot of people completely forget this step. An underinflated spare is almost as bad as the flat you just replaced. Donut spares in particular need around 60 PSI check your owner’s manual or the sidewall for the correct number.

What If You Don’t Have a Spare at All?

Quite a few newer cars actually ship without a spare tire. Manufacturers aren’t required to include one, and many models skip it entirely to save weight and trunk space. If you’re not sure whether your car has a spare, check your trunk or under the vehicle some trucks and SUVs store the spare underneath the chassis.

If you don’t have one and want to get one, measure your trunk space first. Compact cars usually can’t fit a full-size spare, so a donut may be your only option. And don’t forget the tools — a spare tire without a jack and a lug wrench is completely useless. Make sure you have both, and that you actually know where they are before you need them.

The Bottom Line

A spare tire is exactly what it sounds like  it’s spare, temporary, a plan B. It’s not meant to replace your regular tire; it’s meant to buy you enough time to get somewhere that can. Keep your speed under 50 mph, don’t try to stretch it past 70 miles, and get a proper replacement fitted as soon as you can.

And while you’re at it check your spare pressure every few months. The last thing you want is to pull out a flat spare when you already have a flat tire.