You know, spare tires are a severe source of angst amongst new car buyers. You spend $30,000 plus on a brand new car and what do you get with your choice of trim? A spare tire that will barely support a child’s wheelbarrow. It’s called a donut for a reason and honestly, how long can you drive on a spare tire?

As it turns out, roughly 50 miles and at speeds no faster than 50mph. Normally, with a new car purchase or, even a used car purchase, it comes with a donut, which has a much smaller diameter in comparison to your standard tires and is meant for emergencies only.

It kind of makes you rethink your original trim choice, doesn’t it? It may be reassuring to know that the 50-mile distance isn’t necessarily set in stone. Drop your glove box, pull out your owner’s manual, and be sure to check it over. Some spare tires are rated for longer distances.

Why are spare tires so limited?

The idea behind the donut is that it just needs to do enough to get you down the road and to a mechanic. Of course, that doesn’t take into consideration that 97% of the United States is rural. That’s great for a fishing trip and not so great for a flat tire with a limited spare.

According to the “experts” spare tires designed to be small and compact are simply the better option, mostly because they save space.

Pros Cons
Smaller and more compact Severely limited in mileage
Cheaper Severely limits your top speed
Less weight Useless if you’re miles from a stop
Quick and convenient
Temporary solution

If you happen to be caught out in the middle of nowhere, miles away from the nearest shop or home, all you can do is mount the spare donut and pray that it gets you there.

As a manufacturer, it is simply more affordable and has a smaller impact on their bottom line to include a donut with all of their new vehicles. It also saves space and weighs less than a standard spare tire.

In other words, look at all the trunk space you get with the new and improved (insert model here), because it’s always reassuring to know that you have plenty of storage space when you’re stuck out on the side of a highway.

What happens if you drive too far on a spare tire?

At some point in your life, you’re probably going to have a flat tire out in the middle of nowhere, a long way from an appropriate place to stop. So you may be curious as to how much mileage you can get out of a donut before things become dangerous.

Most spare tires are rated for 50 miles, although you will occasionally come across some that have a rating of 70 miles or even 100. However, 100 is the absolute maximum that you can safely expect to get out of a donut spare.

Driving too long on one is not only dangerous for you, it’s dangerous for your vehicle as well, at least in terms of the kind of damage it can do.

  • Exceeding the mileage puts you in danger of a blowout
  • It can damage your suspension system
  • Damage to the transmission is possible as well
  • Your brake system can experience problems
  • Damage to your differential

How in the world can a spare tire damage your transmission? Well, it’s a matter of what we call the “cascade” or “domino” effect, and it all starts with the differential. The differential is designed to keep your wheels spinning at the same rate when you are driving straight.

When you go into turns, the differential adjusts the trie spin for each wheel, individually, for the best traction and comfort on the road. When you have a spare tire on with a smaller diameter, it spins faster than your standard wheels, which throws off your differential and overworks it.

Overworking the differential causes two things: overheating and grinding. The overheating ruins the fluid inside of it and the grinding adjustments create metal shavings that are dispersed into the overused fluid.

Unfortunately, that fluid is the very same fluid that operates within your transmission, cooling and lubricating the moving parts. The domino effect. Driving for too long on a donut has the potential to cause a catastrophe of mechanical failures that will eat your bank account alive.

None of that includes the damage that a donut spare can cause to your suspension system, brakes, and the potential for having another blowout on the side of the road. The important thing is, if you have to use a donut spare, make it as short-term as humanly possible.

Can you drive with a spare tire on the front?

Black jeep Colfax
Photo by JD Weiher / Unsplash

Unless you have one of those weird cars with the engines in the trunk or a 1972 Volkswagen Beetle, you should be very limited and very careful putting a donut spare on the front of your car.

The problem is, the vast majority of the vehicle’s weight is in the front, so that’s a lot to ask of an emergency, temporary tire. That’s not to mention the fact that the front axle is the steering axle, so you have a lot of weight and a lot of precision controls depending on that little booger of a tire to stay strong.

The best part is, you don’t have to do it that way. It’s a far safer option to simply get the spare donut on the rear. It does take a little more work, however, when it comes to you or your family’s safety on the road, a little extra work is more than worth it.

Instead of changing the front flat tire, set your jack close to a rear tire. Remove it and replace it with the donut spare. Then take the back tire to the front, changing them out for one another. This way, you’re not putting all of that weight on a shady donut tire.

If nothing else, it will buy you a little more time on the road, improve your ability to completely control your vehicle, and drastically improve the safety of your vehicle on the road.

Can you drive on a spare tire in the rain?

Driving in the mountains
Photo by Morgan Rovang / Unsplash

Rain waits for no one and it certainly isn’t going to let up on you just because you have a flat tire and are caught out in the open. If that’s the case, then you ultimately have little choice, unless there is a haven where you can park it for a time until the rain passes.

There are understandable situations where you may have to drive in the rain with a donut, however, it’s not advisable to do so if you can help it. Since donut tires are much smaller than your standard tires, that means there is less rubber on the road. Less rubber means less traction.

You also have limited control as well. These two problems are exacerbated in a rainstorm, even if it’s a light sprinkle. What most people don’t understand about rain, is that it is the initial shower that is the most dangerous.

As time goes by, as well as hundreds, if not thousands of vehicles, transmission fluid, oil, brake fluid, power steering fluid, and antifreeze that leak from vehicles old and new, stack up on the highway.

The fresh rain gets these fluids moving again, raising them off of the blacktop like the dangerous head of a snake. Getting caught in a rainstorm, right at the beginning and before the rain washes these fluids from the road, is the most dangerous time, and hydroplaning is more common.

How long do spare tires last?

Occasionally, you may find that a spare tire has remained buried under the plastic flap in the trunk or chained to the bottom of a truck for many, many years. It’s common enough to be concerned over whether or not it’s still safe to use.

The average lifespan of a spare tire is 7 to 10 years. If you happen to have a spare tire that is older than 7 years, you should get it inspected or replaced. If it’s older than 10 years, opt for a replacement altogether.

Even rubber doesn’t last forever, despite its resistance to rot and degradation over time. There is, after all, a big difference between a rubber tire laying on the ground and one that is concealed in the trunk of your vehicle.

Either way, however, it’s always safe to just get a new one or replace it rather than risk using it and having it fail you while you’re traveling 50mph down the road.

Final thoughts

Spare tires are certainly useful and there’s no getting around that. Unfortunately, they aren’t the best of quality when it comes to putting on a spare on the side of a highway, and driving the vehicle where it needs to go.

Just remember to keep it limited to no more than 50mph and no more than 50 miles if it can be helped at all. Once you have your tire fixed, invest in a real spare, as it will save you a lot of headaches and improve the safety of you and your family.