Are Over-Inflated Tires Safe to Drive On?

When Old Man Winter comes calling, not only does he bring a lousy nip to your nose, but he'll also mess with air pressure in the tires on your car. You might even have the Tire Pressure Monitor System (TPMS) icon appear. That means a discrepancy in tire pressure has been detected. Tap or click here for our guide to understanding TPMS.

So why do you need to worry about tire pressure during winter? The answer is simple. Because when it gets cold outside, the air pressure in your tires shrinks. It's science, which we explain in another post about winter tire pressure.

That post led to other questions regarding tire pressure: How much tire pressure is too much? Is it OK to over inflate tires? And, why would someone want overinflated tires?

What Does It Mean to Over-Inflate Tires?

Over-inflating tires mean you've put more air in than the maximum PSI that is recommended. When discussing over-inflated tires, we're referring to tire pressure measured in pounds per square inch (PSI). 

Tires have a recommended PSI rating, which is the maximum PSI the tire can handle. The PSI is found in your vehicle's owner's manual, on the sticker inside the driver's door, and also on the tires' sidewalls.

So how much tire pressure is too much?

No, your tire isn't going to explode if you add a little more than the recommended amount of air. But you shouldn't go too much over recommended PSI. You can safely over-inflate tires by up to 10%. For example, if your tires have a recommended PSI of 35, you can go up to around 38 PSI without worry. Anything more than that is too much and not recommended. Read on to understand why.

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What Can Happen If You Put Too Much Air in Tires?

Driving with over-inflated tires can lead to several problems. The most problematic is a blowout, as they are more likely to occur with over-inflated tires. A tire blowout puts you and other drivers on the road in danger because it can cause you to lose control of your car.

Furthermore, many safety features on your car, like the anti-lock brake system, are made to function when the tires are inflated according to the manufacturer's specifications. Over-inflated tires may jeopardize some of your car's driver assistance features.

Finally, overinflated tires could void your warranty (as well as underinflated tires). Read the fine print on your tire manufacturer's warranty to understand their requirements for proper inflation. 

How Can You Tell If a Tire Has Too Much Air?

Beyond checking PSI with a tire gauge, there are symptoms of over-inflated tires to watch for, including excessive wear on the tire's center treads, an uncomfortable and bumpy ride, a lack of traction and an oddly behaving vehicle.

What do we mean by an oddly behaving vehicle? We mentioned earlier that some of your car's safety features could be impacted by over-inflated tires. This can also change how your vehicle handles due to its electronic stability control system. It can cause the system to receive incorrect signals from the wheels and try to control your car in strange ways.

Why Would Someone Want to Overinflate a Tire?

Most over-inflated tires are by mistake. However, some people believe that it could improve gas mileage. Who could blame you with gas prices so high?

Because underinflated tires contribute to higher gas mileage, some people believe the opposite to be true: Overinflated tires save gas mileage. This isn't true. Overinflated tires do not improve your gas mileage, at least not enough to make a noticeable difference at the gas pump. 

Another reason could be that all tires lose air over time. The most common causes are osmosis and temperature changes. To prevent having to add air, some might put more in than recommended. Don't do that. Again, risk versus reward.

Because overinflated tires increase your risk of being in an accident, we don't recommend over-inflating tires, for any reason.

What Are the Dangers of Overfilling Tires?

We mentioned safety concerns and car handling issues earlier. But there are more potential issues with over-filling tires, primarily tire damage.

Over-inflated tires are stiffer than they should be. This makes them more susceptible to damage from running into curbs, driving over potholes or other debris. It can also distort the tire's shape, leading to decreased traction and increased wear, especially in the center of the tire.

Will Over-Inflating Tires Void Their Warranty?

The quick answer is yes. To keep a tire warranty valid, you must do a few things. One, you must keep the original receipt from the tire purchase. Next, you must follow regular guidelines, including rotating tires according to the manufacturer's recommendation and keeping the tires properly inflated. Over-inflating them can, in fact, void the tire warranty. So can under-inflating them.

What To Do If You Put Too Much Air in Your Tires

So you've put too much air in your tires. Now what? No worries. It's a simple fix. All you need to do is let some air out of the over-inflated tire. Here's how to reduce tire pressure:

• Rotate the cap counterclockwise to detach it from the stem. A metal pin is located inside the stem's middle.
• Grab a flat-head screwdriver, set the top over the metal pin, and then push it inward. Through the valve stem, the tire will start to release air. You'll be able to hear air leaving the tire.
• After removing the screwdriver, use your gauge to check the tire pressure.
• Repeat the steps until you reach the ideal tire pressure. Once the air pressure is correct, attach the cap back to the valve stem.

Tip: Do this when you're near an air pump, just in case you let too much air out! Don't worry if you let too much air out; you can always add some back in to get to the recommended PSI.