Your tires are the unsung heroes of your vehicle - the rubbery guardians that stand between you and the unforgiving pavement. They're the superstar ensemble cast of your car's safety performance, yet they often go unnoticed and unappreciated until they quite literally start to fall apart at the seams, revealing their inner guts or developing unsightly bulges.
Let's face it, a tire that's worn down to the nub is like driving on borrowed time, but a tire with a bulge? That's a ticking time bomb ready to go "pop!" at the most inconvenient moment. And yet, countless drivers continue to roll the dice, cruising around with bulging tires as if they're just another harmless quirk.
Many people assume that a little bulge is no big deal, just a cosmetic blemish that doesn't warrant immediate attention. But don't be fooled! In most cases, a tire bulge is a serious red flag, and you should start looking for solutions before it's too late.
In this article, we'll dive into the wonderful world of tire bulges, exploring what causes them, the risks they pose, and the best course of action for dealing with these pesky rubber protrusions.
But first, let's get serious and peel back the layers of a modern radial pneumatic tire and discover the magic that lies within. It's time to give your tires the attention they deserve!
- What is Inside a Tire?
- What is a Tire Bulge?
- Is it Safe to Drive with a Tire Bulge?
- Can You Fix a Tire Bulge?
- Major Causes of Tire Bulge
- How to Prevent Tire Bulges?
What is Inside a Tire?
The wheel was by far the biggest innovation in mobility. It allowed the first civilizations to move people and goods at very long distances and literally changed the trading landscape.
But the wheels of the past had limitations – they weren't gripping the roads well, were very uncomfortable, couldn't carry very heavy loads, and damaged the roads quite a lot. Even today, we can see wheel marks on roads from Ancient Rome and even some older civilizations.
But the modern pneumatic tire solved all those issues by using pressurized air to carry higher loads, increase wheel-to-road contact, and improve comfort. The innovation quickly changed the automotive industry and allowed for more capable, comfortable, and faster cars. Today, we should thank the modern pneumatic tire for having the ability to travel with our families at very high speeds, in absolute comfort.
However, although many people think the pneumatic tire is just rubber attached to a rim, that's far from the truth. Rubber is a very elastic material that won't be able to carry very heavy loads, even with the help of pressurized air. For that reason, the pneumatic tire also includes several reinforcements to help it cope with the added loads, particularly under acceleration, braking, and turning.
The first reinforcement under the tread of the tire is the belts – usually two, but more on larger tires that need to carry heavier loads. These belts are usually made from steel, but they can be made from other strong materials. The belts help with the tire's structural integrity, provide sharper handling, and resist punctures.
Under the steel belts, you'll find plies (cord carcass) made from polyester, nylon, or rayon, which give the tire strength and flexibility. Thanks to these plies, the tire keeps its shape under heavy loads, like high-speed cornering, braking, and strong acceleration. The plies also help with puncture resistance, run in radially across the tire (radial tires), and also cover the sidewall. In the past, they ran across an angle to create bias-ply tires, but those are today mostly out of use for road cars.
Furthermore, under the steel belts and plies, there is a rubber insert that keeps the pressurized air inside, which along with the sidewalls, keeps the pneumatic tire as a whole.
So, now that you know what's inside a tire, you can imagine what a tire bulge means, right?
What is a Tire Bulge?
A tire bulge (or bubble in tire) is an irregularity on a pneumatic tire that looks like a raised, swollen area. It can appear on the sidewall and the tread of the tire and can happen due to a damaged or compromised internal structure.
For instance, if the belts or plies inside the tire are somehow bent or torn, they will create an area of less resistance for the air to punch through. And since air always wants to go to weak spots, it will start puffing up the rubber compound that encapsulates the whole tire.
Rubber is more elastic than steel belts, and nylon plies and hence will start to bulge under high air pressure, similar to a balloon. This would lower the structural integrity of the tire and make it much more susceptible to changes in load due to high-speed cornering, acceleration, braking, or carrying heavy items.
But is there a difference between a bulge on the tread and a bulge on the sidewall?
1. Bubble in Tire Sidewall
Tire bulges most often appear on the sidewall simply because there is much less material there. Unlike the tread, the sidewall only consists of the cord carcass (plies) coated in rubber, without any steel cords to hold everything together. It's the pressurized air that keeps the structural integrity of the sidewall, so it's crucial to always keep your tires properly inflated.
When a tire bulge shows on the sidewall, it usually means that some of the cord plies in that area were damaged. It's a very dangerous occurrence that requires immediate attention!
2. Bulge on the Tread
Tire bulge appearing on the tread of the tire is a much less common occurrence, but it still happens. The main culprit is a broken belt, which would significantly weaken the construction of the tire, leading to a bulge. Like with a sidewall bulge, you should immediately take action when noticing a tread bulge.
Is it Safe to Drive with a Tire Bulge?
No, it's not safe to drive with a tire bulge. Thus, I strongly recommend replacing your tire with a spare. However, if you are in the middle of nowhere and only have a tire repair kit in the, you could continue driving, but don't exceed 40 mph. Also, refrain from accelerating or braking hard, and only enter corners at very low speeds. You could also underinflate the tire a little to make the bulge smaller.
A tire bulge can be very dangerous as it can cause a sudden blowout, but it mostly happens at higher speeds and loads. Therefore, smooth and slow driving is crucial to keep you safe. Still, driving for too long with a bulge can cause it to expand, and then a blowout could happen even at lower speeds. So, only drive with a tire bulge in case of emergency, i.e., to reach the closest tire repair shop.
Can You Fix a Tire Bulge?
Although some jerry-rig mechanics or tire technicians might suggest you could repair a sidewall bulge, that's sadly not the case. The tire on your car is manufactured using very expensive, state-of-the-art machinery that combines all components into one structurally sound package, and no technician can repair anything inside.
In other words, repairing the tire bulge would require the replacement of the structurally-damaged cord, which is not possible in a tire repair shop. Some heavy-duty truck tires can be retreaded (recapped), but that only replaces the uppermost rubber layer (tread) and not the casing inside. This, even retreading, won't solve a tire bulge.
Major Causes of Tire Bulge
1. Manufacturing defects (usually in cheap tires)
If you notice a tire bulge on your new and shiny tires, it might be due to a manufacturing defect. Now, these don't often happen on high-quality tires from reputable manufacturers but are a common occurrence on cheap tires from companies with no experience in developing and manufacturing tires.
Most often, manufacturing defects happen because of improperly developed tires with sub-par materials that can't carry loads of regular driving. These can cause inconsistencies inside the tire and make it structurally weaker, so even some smaller road imperfections or driving on the highway could create a bubble in a tire.
For that reason, I always recommend purchasing tires from reputable manufacturers. These companies spend time and money to develop their tires, test them for thousands of miles, and use state-of-the-art manufacturing processes that minimize manufacturing defects.
2. Impact damage
Hitting a deep pothole with sharp edges puts a lot of strain on the tire's internal components, but the same is true with curbs and other road hazards. This is especially true for steel belts and cord carcasses, which have a point at which they lose their elasticity, which leads to permanent distortion or even breakage. It could also lead to cord separation, which can also create a tire bulge.
3. Inappropriate tire maintenance
Regularly checking the tire pressure isn't only important to ensure your vehicle performs at its best, but it also keeps the tires from damage. Underinflation, for instance, puts more strain on the internal tire components because there is not enough air to support the tire. As a result, the belts and plies are more susceptible to impact damage, which could lead to tire bulges.
However, overinflated tires can also put more strain on the belts and plies, but this time from the air pressure inside the tire. In this case, even smaller irregularities in these components could yield under pressure. And since air always goes through the path of least resistance, it would create a bulge on the rubber layer.
4. Overloading the vehicle
Much like with overinflation, overloading your vehicle will also put more pressure on the internal components of the tire and lead to tire bulges. Therefore, it's crucial to follow the manufacturer's recommendations for the maximum load capacity of your car, particularly when carrying heavy cargo or towing.
5. Aged or worn-out tires
Using your tires past their intended lifespan can create all sorts of issues, including tire bulges. This is true for tires that don't have enough tread left but especially for tires that are just too old. This is because changes in temperature, air humidity, and the sun's UV rays weaken the tire structure and make it more susceptible to damage from various road impacts.
Therefore, it's crucial to replace your wheels on time. For mileage, it depends on the type of tire – all-season touring tires can usually go for 50,000 to 60,000 miles before there is not enough tread left, but summer performance tires will be worn-out after only 20,000 miles! So, always make sure to have a tread depth gauge on hand or ask your tire technician how much life is left in your tire.
But even if there is enough tread left on your tire, you should use it for a maximum of eight years, but only when stored properly! If your car was facing the sun or was placed in a humid garage, you'll need to replace them even sooner to minimize the chance of tire bulges appearing.
6. Punctures or cuts that damaged the casing
Every puncture weakens your tire as it goes through all internal components. In most cases, punctures can be repaired, and you'll be good to go, as the belts and plies won't be damaged to the point of losing structural integrity.
However, some punctures could cause significant damage to those components and lead to a tire bulge after inflation. Sadly, when that happens, you'll need to replace the tire.
How to Prevent Tire Bulges?
I would say just follow the major causes or tire bulges and act upon them. In other words, inspect the tire regularly for irregularities, like bulges or cords showing. Furthermore, make sure you keep your tires inflated at the correct pressure and rotate them regularly to ensure they last longer.
You'll also want to drive cautiously and avoid road hazards like big potholes, curbs, and various debris, and never overload your car. Finally, replace your worn-out or old tires on time, and purchase new tires from reputable manufacturers!
Tire bulges are a very common occurrence in the automotive landscape and one of the major causes of tire blowouts. According to the U.S. National Highway Traffic Safety Administration (NHTSA), tire-related issues, including blowouts, contribute to approximately 11,000 crashes each year in the United States.
So, take the tire bulge seriously and act upon it immediately. If not, you risk your own safety, but it could also potentially hurt your family, friends, and other traffic participants. By taking care of our tires, we can significantly increase road safety, leading to fewer accidents and deaths.
We might take driving a car for granted, but it's a dangerous process by itself, and that's only exaggerated if it sits on worn-out tires with a tire bulge!
I’m Ivo Gievski, the content writer for Tireer. We built our website with over 15 years of experience and extensive research in the automotive and technology sectors. My dedication to delivering high-quality content is unwavering, and I strive to continuously hone my skills to stay ahead of industry trends and provide readers with informative, engaging, and valuable insights.