Why Do Spare Tires Get Hot?

Why Do Spare Tires Get Hot? (Discover the Unexpected Causes and Solutions)

You’re halfway through that summer road trip, your car humming along to the rhythm of the open road. You’re practically feeling the soft sand between your toes at your beach destination. But wait, you’re not quite there yet. There’s one small nuisance you need to understand: why do spare tires get hot? You know how to drive, but how well do you understand the quirks of your vehicle?

Last summer, I embarked on a cross-country trip, covering countless miles under the scorching sun. On one of my pit stops, I noticed my spare tire was hot, much hotter than I initially thought it would be. I had one mystery left unsolved, and I was determined not to let it ruin my journey. So, I put on my detective hat and got to work.

Here’s what I learned, the steps I took, and how I discovered answers to a question that had been heating me up more than the summer sun: Why do spare tires get hot? It turns out, it’s not just about the weather or the car’s speed. Let’s figure this out together, shall we?

Why do spare tires get hot?

Have you ever wondered why your spare tire feels hot to the touch? Well, you’re not alone. Spare tires, like all other tires, have a tendency to heat up, especially after a long drive. This phenomenon isn’t just unique to spare tires; it’s a common occurrence in all types of tires. But why exactly does it happen? Let’s delve into it.

Understanding Heat Absorption in Spare Tires

Let’s start by understanding how heat is absorbed in spare tires. When you’re driving, your tires are constantly in motion, rolling against the rough asphalt. This action results in friction, which in turn, generates heat. Now, imagine this happening over and over again during your drive. Even though the spare tire isn’t in direct contact with the road, it still absorbs some of this heat through the car’s chassis.

The material of the tires also plays a crucial role. Tires are usually made of rubber, a substance known for its heat absorption capabilities. It’s not the color of the rubber that matters but how the rubber itself reacts to heat. As I’ve observed from my experience, rubber creates friction and grip, which leads to the generation and absorption of heat.

The Science Behind Temperature Rise in Tires

Now, let’s get a bit scientific. You see, all materials, including rubber, have something called viscoelastic properties. This means the material can exhibit both viscous and elastic characteristics when undergoing deformation. In simple terms, tires store more energy during compression (as they roll) than they release. This excess energy is then dissipated as heat, causing a rise in tire temperature.

Think of it this way: every time the tire rotates and deforms, it’s like it’s doing an intense workout, and just like when you workout, your body (or in this case, your tire) heats up. This process of heat building up due to energy dissipation and deformations is what’s happening each and every time you hit the road.

Thermal Expansion: A Key Factor in Tire Temperature

On the topic of tire temperature, we can’t overlook the concept of thermal expansion. From my experiences, higher temperatures lead to greater tire pressure, and this can potentially cause overinflation. Contrarily, lower temperatures lead to lower pressure. This is why you should regularly check your tire pressure, especially before going on a long journey.

Did you know? Tires can lose or gain 1 PSI for every 10℉ change in temperature. That’s why it’s critical to monitor your tires as the weather changes.

The Risk of Tire Overheating

Moving on, let’s discuss the risks associated with tire overheating. Just like any other part of your vehicle, consistent high temperatures can cause damage to your spare tire. This risk increases if the tire is overinflated, as the increased pressure can lead to tread separation and in worst cases, blowouts.

How Overheating Can Affect Spare Tires

Overheating can have detrimental effects on your spare tires. One of the primary concerns is the degradation of the rubber due to oxidation. This can be attributed to prolonged exposure to oxygen and warm temperatures, which can change the tire’s properties. Remember, degraded rubber can cause sidewall rupture or tread separation while driving, which could lead to severe accidents.

Preventing the Risk of Spare Tire Overheating

Preventing your spare tire from overheating should be part of your regular car maintenance. Some simple steps can help reduce the risk significantly. For instance, before embarking on a long journey, ensure you’ve checked the air pressure in your spare tire. Having the correct pressure not only reduces overheating risk but also prepares your spare tire for use in case of an emergency.

Another tip I’ve found useful is to turn off your air conditioner and open your windows when the car starts to overheat. This reduces the engine load and subsequently the overall heat generated by the vehicle. And of course, always park your car in the shade whenever possible to prevent direct sunlight from contributing to the overheating of your spare tire.


Now, let’s cover some frequently asked questions about spare tires and heat. These are questions I’ve encountered numerous times in my years of experience, and I believe the answers will provide you with a clearer understanding of the subject.

Is it Normal for Spare Tires to Get Hot?

Yes, it is normal for spare tires to get hot, especially after a long drive. As I’ve mentioned before, spare tires absorb heat from the car’s chassis, and this leads to an increase in their temperature. However, if you notice your spare tire getting too hot or heating up when you haven’t been driving, that could be a sign of a problem, and you should have it checked out.

Why Spare Tire Looks Flat: Myths and Facts

One common myth is that your spare tire is flat because it’s smaller than the rest of your tires. However, this is not the case. Spare tires, especially the ‘donut’ type, are designed to be smaller and thinner to save space and weight. They’re not meant to replace your regular tires for a long-term basis; they’re a temporary solution to get you to a service station.

Remember, spare tires are prone to slow air loss and temperature fluctuations, which require regular air pressure checks. It’s a myth that you can drive normally on a smaller-sized spare tire. As a matter of fact, manufacturers recommend not driving more than 50-70 miles and at speeds no faster than 50 mph on a donut spare tire.

Effects of Hot Spare Tires on Vehicle Performance

While spare tires may not seem to directly affect your vehicle’s performance, they can cause issues if not properly maintained.

Hot Spare Tire: A Potential Car Problem?

A hot spare tire can indeed lead to potential car problems. For instance, if a spare tire becomes too hot, it might cause a blowout when you eventually need to use it. This is why it’s crucial to regularly inspect your spare tire and replace it as necessary. According to CR’s tire program manager, it’s recommended to replace your spare tire every 10 years for safety purposes.

In conclusion, a little knowledge can go a long way, and knowing why your spare tire gets hot can save you from potential car problems. Always remember to check and maintain your spare tire regularly, and you’ll be prepared for any situation on the road. After all, it’s always better to be safe than sorry.