Air Bubble in Tire Sidewall (7 Causes)

Although common, tire bulging or air bubbles on the sidewalls is not normal. If anything, it indicates that something — your tire skeleton, sidewall cords, or inner layer (to name a few) — is damaged or about to come loose inside your tires. What causes bubbles in tires in the first place?

Here are the top causes of a bubble in your tire sidewall:

1. Driving with a flat tire
2. Underinflation
3. Low temperatures
4. Impact damage
5. Overloading
6. Manufacturing defect
7. Lack of caution

If you have experienced tire bulges, you may already be adept at resolving some of these culprits. Otherwise, the above list should be a good enough reference.

Continue reading and learn more about a tire’s anatomy, causes and fixes of tire bubbles, frequently asked questions about the topic, and more.

The Anatomy of a Tire

Even without extensive knowledge of different tire brands and rubber compounds, any vehicle owner would know that tire damage is the main culprit behind a bulging tire.

Air pressure is supposed to be contained inside the tire. So unless the sidewall has sustained some form of damage, only then will there be gaps for air to travel through and fill.

That said, getting acquainted with the composition of an average tire is crucial to better understanding tire bubble causes and how to prevent them. For starters, let us take pneumatic tires as an example.

Solid and Air-Filled

Pneumatic tires fall under two types — solid and air-filled. Solid pneumatics are tires made predominantly of rubber, increasing their resistance to puncture. On the other hand, air pneumatics are either tubed or tubeless tires filled with air. For this article, we will delve into the composition of the latter.

As defined by Tire Rack, “pneumatic tires are made of specialized rubber compounds reinforced by plies of fabric cords and metal wires.”

The cords and wires give the tire its shape, while the rubber compound dictates its stretchability and determines how much cold-tire pressure it can contain. Functionally, these components are inversely proportionate and only held together by rubber and strong adhesive.

These tire components should hold together until the tire reaches its service limit. However, this is often not the case.

Tires (especially pneumatic ones) are susceptible to premature wear and damage, given that they are utilized for outdoor applications most of the time. When this happens, you would see cracks or tire bulges on its surface.

It is worth noting, too, that a tire’s profile contributes immensely to its susceptibility to bubbles or bulges in the tire sidewall. Tires with taller profiles, for instance, would be able to withstand more severe impacts from deeper potholes and sharper curbs before giving out.

Low-profile tires on large-diameter rims are more likely to develop tire sidewall bubbles sooner since their rubber compounds are more thinly spread out.

Sidewall Separation or Air Bubble in Tires

These telltale signs usually manifest within the first six months of a tire’s life cycle or during a period when they are still quite negligible and not yet a considerable detriment to tire strength. But because they can be easy to ignore, they continue to grow in size and escalate into other complications leading to ultimate tire failure.

Given this scenario, spotting bubbles on tires early on and identifying the cause behind tire bulging has become increasingly significant. And what better way to enhance this necessary skill than by familiarizing oneself with its many causes!

What Causes Bubbles in Tires?

1. Driving With a Flat Tire

Many of us are guilty of this act at least once. Some may be drawn to pushing their tires to the limit, while others may have done so out of necessity. Whichever the case, driving with flat knobbies is not without repercussions.

If done repeatedly, this behavior causes your tires to come in contact with foreign objects. Additionally, the grooves on the tire shoulder are rendered ineffective in absorbing bumps.

The rim can also press against the tire material, aggravating damage to the tire’s internal lining and resulting in tire bulging.

Having a tire pressure gauge (view on Amazon) ready in your trunk is one way to temporarily resolve this problem. Plugging the puncture and inflating the tire to spec should buy you enough time to get home or arrive at your local auto shop.

However, I recommend doing these steps only as a last resort. You will be better off swapping your busted knobbies with your spare tire — to ensure you get to safety.

2. Underinflation

Underinflated tires are not as bad as driving with flat tires. However, they are not less dangerous. Not inflating your wheels to spec still causes the production of excessive heat, which is detrimental to the bonding adhesive used to hold the different tire materials together. Once this intermediate bonding weakens, air bubbles emerge faster.

If done deliberately, all that is required to rectify the situation is to inflate your tires to spec. Otherwise, consider a possible air leak. If so, it would be best to find the source of the leakage and address it immediately before taking your car out for another drive.

3. Low Temperatures

Car owners in colder regions are more prone to experiencing earlier episodes of air bubbles or tire bulges, even if they are stringent with tire maintenance.

Low ambient temperature — or even a temperature drop — is enough to reduce tire pressure. This can be easy to ignore in colder climates. When left unattended, the drop in cold-tire pressure will soon cause air bubbles in the tire walls.

4. Impact Damage

Curbs, potholes, and other road hazards are well-known causes of bubbles in the tire sidewall. Other contributors to impact damage are as follows:

• Debris
• Heavily damaged or dilapidated roads
• Railroad crossings
• Road construction areas
• Severely uneven surfaces
• Speed bumps

These roadblocks pinch the tire or sidewall material “between the rim and the road.” The incident could cause a tear or hole inside the tire liner layer, sidewall separation, or damage to the sidewall cords. All these outcomes weaken the tire, resulting in breakage or air bubble formation.

A workaround to this situation is to traverse an alternate route with better terrain conditions. However, the chances that all drivers have this option are slim to none.

The only other way to avoid impact damage to your knobbies is to be more cautious while driving — especially if you have low-profile tires like Nitto Motivo Radials – 225/45R17 94Z XL (view on Amazon).

5. Overloading

Going beyond the maximum load limit of your car is never a good idea because it wreaks havoc on at least two components of your vehicle. One, your drivetrain and transmission suffer. And two, your tires wear out or get damaged prematurely.

Continually ignoring your vehicle’s payload limit can result in bubbles in the tire sidewall. This will eventually translate into unnecessary expenses as you would have no choice but to replace your tire, as well as on-road safety risks.

Thankfully, staying within your four-wheeler’s capacities is 100% controllable and entails just a bit of discipline. Refer to your owner’s manual for your car’s payload limit and keep within that threshold.

Also, remember that wheel size has no real positive effect on payload capacity. That said, using wider or larger tires would be futile to increase your vehicle’s maximum weight limit.

6. Manufacturing Defect

Bubbles in tire sidewalls can result from internal tire defects or a detached sidewall layer, not just from collision or driver negligence. However, these are one-off situations that only come to light after thoroughly inspecting a brand-new set of tires.

Contamination or incomplete bonding is typically the problem, with symptoms appearing within the first six months of the tire’s life cycle.

Because a tire is composed of several materials with differing properties, an OEM would need to use a strong adhesive to bind them together.

Suppose a manufacturer suddenly decides to cut down on the quality of adhesives used or the timing of hardening and curing the tire layers. In that case, sidewall separation and tire bulging will likely be outcomes.

Sadly, damage to the shoulder or sidewall cannot be repaired, meaning that sidewall separation can only be resolved by tire replacement. And in most cases, drivers replace all four tires to ensure even wear, balance, and alignment.

7. Lack of Caution

Recklessness is an underlying factor in all items listed in this section, except those beyond the vehicle’s owner’s control. Some drivers get a kick out of driving like “The Fast and the Furious” cast members. But to do so while throwing caution to the winds is folly.

In the case of speed bumps, air bubbles could be easily prevented if people only took the time to drive over them at moderate speeds. The same goes for driving over on-road objects at the right angle. But because we often drive in haste, we neglect to pay attention to these things — at the expense of a damaged tire.

This is not to say that our lack of caution is always deliberate. Sometimes, it stems from non-familiarity with a particular route. Drivers tend to approach these unfamiliar roads aggressively (sometimes inadvertently).

The only solution to this is becoming an intentional driver. Sure, you would not always know the conditions of a new route beforehand. But if you do, it is best to approach these thoroughfares with restraint.

Frequently Asked Questions

Are Tire Sidewall Bubbles Covered Under Warranty?

Warranty covers tire sidewall bubbles but not entirely. The only time you can hold a manufacturer completely responsible for replacing your knobbies cost-free is if an OEM defect has been proven.

Note, however, that warranty claims are time-sensitive. Even if the air bubbles were the manufacturer’s fault, you would only be able to demand free replacement if you do so promptly.

Tire Sidewall Bulge Fix Cost

Unfortunately, no amount of patchwork or adhesive can fix tire bulging and air bubbles. The only way to go about the problem is by completely replacing the affected tire.

Depending on your tire type, you may shell out between $200 and $650 per tire. These figures can go up if there are other complications associated with the tire sidewall bulging — for instance, warped wheels resulting from impact damage.

If only one tire is affected, merely replacing it with a new one will likely delineate the rest of your knobbies. The best course of action to prevent this from happening is to replace all four tires. Hopefully, you have road hazard insurance to help offset your expenses.

Is It Safe to Drive with Tire Bubbles?

The answer is no. Although you would still be able to if you tried, driving despite knowing that your tires are impaired is counter-intuitive. Even if these bubbles appear small on the surface, they indicate a compromised tire.

Tire sidewall bulges signify that your tires are on borrowed time, and continuing to drive on them can only mean an impending accident.

How Long Can You Drive on a Bubble Tire?

I believe the more appropriate question is, “How should you drive on bubble tires?” as it is not safe for anyone to continue driving with bubbles showing on the tire sidewall. But if the situation cannot be helped, then heed the suggestions below:

• Do not exceed speeds of 35 mph (56 km/h)
• Stay away from potholes and other road irregularities
• Avoid hard acceleration and braking

Again, drive only if you need to get to safety. Once you have reached your destination, prioritize resolving your tire bubble issue and replace affected tires as needed.

How to Fix Air Bubble in Tire Sidewalls

There is no actual fix to air bubbles. When tire bulges become visible, the internal damage to tire components is far gone.

The best route to take is prevention. And car owners can effectively do this by practicing the following behaviors:

• Driving cautiously and diligently
• Ensuring tire pressure is always up to spec
• Avoid sharp objects and other road obstructions
• Never drive with a flat tire
• Keeping within the vehicle’s payload capacity
• Inspecting the condition of tires regularly
• Regular vehicle servicing

Conclusion – Air Bubble in Tire Sidewall

To recap, here are the most common causes of air bubbles in tire sidewalls:

1. Driving with a flat tire
2. Underinflation
3. Low temperatures
4. Impact damage
5. Overloading
6. Manufacturing defect
7. Lack of caution

Except for OEM defects, every other item in this list is preventable. But sadly, they are not paid mind to. This behavior is largely due to not understanding the nature of the problem and the dangers it poses when left unaddressed.

Hopefully, the information in today’s article changes this mindset. Bulges and other visible deformities on car tires should never be normalized.

Preventive measures should be taken to keep these occurrences at bay. But if the problem already exists, prompt resolution and tire replacement should be the next steps.