Why is There a Bubble on My Tire?

Tire bubbles or bulges are easy to miss—and they can cause accidents and damage your vehicle if left untreated. These egg-shaped bubbles usually form on the sides of your tires due to air leakages within the tire.

But what causes these tire bubbles and how can you fix them? Read on.

Why Do I Have a Bubble in My Tire’s Sidewall?

A bubble in your tire means that its inner layers have been damaged.

Your tire is made of several layers. The inner lining maintains the air pressure inside the tire. Usually, this layer has no extra material to reinforce it like the outer layers of the tire, but it’s made of a strong type of rubber that helps keep it airtight.

However, even if the inner lining is made of strong materials, it can still rupture and leak air if it’s damaged in any way. At first, air can leak out in small amounts. These small pockets of air eventually gather to form larger and more noticeable bubbles due to excessive pressure and other forces.

Once air leaks out from the inner lining, it makes its way to the outer layers. The air collects at a weak spot in the tire where the rubber has been worn and weakened, such as the sidewall.

The sidewall is the smooth side of your tire between the tread to the wheel rim. This part of your tire is made of strong rubber, but it’s also prone to wearing and bulging since it’s thinner than the tread and doesn’t have any cord reinforcements.

The tread area of the tire can be compromised in a similar fashion that may be difficult to spot with a simple visual inspection unless you spin the tire while inspecting it, but you’ll typically hear or feel it when you have tread separation.

What Causes Bubbles in Tires?

An air bubble in your tire means that its inner lining has ruptured and air has leaked out. Most of the time, the bubbles result from impact damage. The weak spot in the tire can inflate as the tire is pinched between the wheel and the road or a curb.

Air leakage can also be caused by driving over bad roads and other external factors that result in impact damage.

Below is a list of road conditions and other factors that can contribute to the formation of a bubble in your tire’s sidewall:

• Crossing large potholes, railroad crossings, and speedbumps
• Repeatedly running the sidewalls against curbs during turns or at the drive-thru
• Driving through construction areas
• Driving over speed bumps at high speeds
• Driving over debris or any kind of material that can damage tires internally
• Driving with a flat tire
• Hitting a road median
• Hauling a load that’s too heavy for your tires
• Driving your vehicle with worn-out or damaged tires

Tire bubbles can also form because of a manufacturing defect, but these are very rare. In these cases, the tire manufacturer may offer a free replacement after careful inspection of the tire bubble and the tire itself.

How to Fix a Bubble in Your Tire

Unfortunately, a tire with a bubble cannot be repaired. Tires simply cannot be fixed once bubbles appear because their layers are already damaged.

Unlike flat tires, tires with bubbles cannot be patched. The sidewall doesn’t have any cord reinforcements like the other layers, so when a bubble or a bulge appears on the sidewall, you can’t repair it because the patch wouldn’t have anything to hold on to.

Once you spot bubbles in your tire/s while you’re on the road, the only course of action is to replace that tire with a spare. Of course, while you’re driving you probably won’t spot them. You’re more likely to see them at the gas pump. The best thing to do is to drive to a repair facility and immediately have the damaged tire replaced.

You can also try to contact the tire manufacturer or the shop where you bought your tires to inquire about warranties.

What to Do if You Decide to Change a Tire with a Bubble

If you decide to change the tire and the problem tire is on a drive wheel on a front wheel drive car, and your spare is one of those space-saving “donut” spares, a non-bubbled tire should be moved from one of the rear wheels to the drive wheel, and the donut should be installed on a rear wheel because on front wheel drive cars, those aren’t connected to the differential.

Driving a long way with the donut on a drive wheel can destroy the differential in the transaxle because the donut is typically smaller in diameter than the other wheels. This isn’t as much of a problem on rear wheel drive vehicles, which typically have more robust differentials, but it still puts those gears through a serious workout than can burn them out if you drive a long way with a donut on one side.

This is a difficult thing sometimes, because about a third of new cars today do not come with a spare tire. Some are equipped with a compressor and sealant kit to temporarily fix a flat tire, which doesn’t help at all if you’re concerned about a bubble in the sidewall. Some spare-less cars are built with run-flat tires designed to operate for a limited distance after losing air from a typical puncture.

But even if you do have a spare, spares can be very annoying to access unless they’re mounted on the tailgate, like on an SUV. And you may be dressed in very nice clothing or you may not be physically able to change the tire. You may have to call road service to handle it if the bubble is severe.

Is It Safe to Drive with an Air Bubble in My Tire?

No, it’s never safe to drive with a damaged tire. However, you may not always have a choice. It also depends on the size of the sidewall bubble. A small sidewall bubble shouldn’t be ignored but might not make it necessary to immediately install the spare.

Furthermore, it is safer to drive on a tire with a bubble than it is to get out of the car in a bad neighborhood or by the road in a heavy traffic area. But in extreme circumstances, the bubble in your tire can burst due to pressure and cause a tire blowout, although that doesn’t usually happen. But with a tire bubble, you need to drive slower than you ordinarily would. It’s especially dangerous if you’re driving at really high speeds, through inclement weather, or on busy roads.

How to Prevent Air Bubbles From Forming on Your Tires

Preventive maintenance is one way to prevent air bubbles from forming inside your tires, but there are other things you can do as well.

Below are some tips to protect your tires from damage and keep them in top shape for longer:

Avoid large potholes and speed bumps

Driving over potholes and speed bumps is one of the main causes of tire bubbles. When you drive over these obstacles, especially at higher speeds, the resulting impact will cause a lot of stress on your tires⁠—which can eventually lead to sidewall bubbles. Also, while turning or entering the drive-thru, be careful to steer clear of curbs and other obstructions that can damage tire sidewalls.

Drive safely

Don’t drive too fast over speed bumps, railroads, and other obstacles. Park carefully and avoid bumping into curbs, sidewalks, and medians.

Also, keep the car moving as you turn your steering wheel in one direction.

Perform regular vehicle checks

Always include your tires when you’re doing a general vehicle check. Check the air pressure often and don’t ignore tire pressure warning lights or messages.

It’s best to spot irregularities in your tires before they get worse. Check out our comprehensive tire inspection guide if you’d like to do this yourself.

Also, remember to always use your owner’s manual or repair manual as references and perform maintenance work according to the recommended intervals.