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What Are The Main Causes Of Bubbles On A Tire’s Sidewall?

Tires are made of layers of rubber that keep the air inside the tire, as well as polyester cords called piles that provide the tire with strength and shape. The layers within the tire are bound to one another using various bonding materials.

How Bubbles Occur

Due to manufacturing defects, driving on damaged roads (for example, hitting a pothole or crossing railroad tracks or other rough patches on the road at high speed), or general long-term wear and tear, the different layers of a tire can lose strength, resulting in a separation of the layers. Once any two layers separate, air can pass through them, forming a bubble in the sidewall or tread of the tire. Bubbles can also form in defective tires if a driver drives on tires that are underinflated.

These bubbles generally form slowly and may not appear overnight. This poses serious driving risks as the driver of the vehicle may be unaware that he or she is driving on a damaged tire.

More information on the age of your tires and other important tire specs can be found in the Florida Department of Highway Safety and Motor Vehicles (FLHSMV)’s tire safety guide. 

Risks

Bubbles in a tire are essentially indicative of a structural failure of the tire. Once one section of a tire is damaged, if the damage goes unnoticed, the damage can spread, with more and more air finding its way to different parts of the tire, forming more – and larger- bubbles along the way.

If the structural damage to your tire – and the resultant bubbles – are large enough, they can result in a clean tire blowout at an unexpected time. Bubbles can also affect your vehicle’s grip on the road, as well as your braking ability.

Precautions and Remedies

Tire bubbles appear more frequently on the sidewall of the tire as opposed to the tread since the rubber and layering of a tire is thinner in the sidewall. Regularly check your tire for bubbles, at least every time you check your tire pressure or fill your tires with air.

Rotating your tires can also help even out the wear and tear that your front and back tires undergo. Tire rotations also provide you with an opportunity to have your tires looked at from up close when they are being switched from front to back or vice versa.

Depending on the cause that is identified for your tire bubbles, you may be eligible for a free replacement or a quick fix by your local tire shop. Speak with your tire dealer for details on available promotions or options.

What you should never do, however, is drive on a tire that has bubbles. You can never predict when a tire bubble will burst, and even seemingly small bubbles can unexpectedly give way and form larger bubbles and cause more internal damage to your tire, all unbeknownst to you. Stay safe, regularly check your tires for structural damage, know where to look for bubbles, and do your best to avoid potholes and other road debris while driving to extend the lifetime of your tires.

For further reading, see the National Highway Traffic Safety Administration (NHTSA) TireWise report, which is a publication that provides useful tire usage guidelines for vehicles of different types.