Imagine this, you’re leisurely driving down the road, and suddenly feel something wrong with the tires. You get out, and immediately spot a puncture, front-and-center on the sidewall! Has this ever happened to you?
Considering the cost of a brand-new tire, it is tempting to simply patch the damage and keep driving. But, is this legal, or would it land you a free stay in jail? This is what we’ll be diving into today.
Simply put, the answer to “Is it legal to patch a tire on the sidewall” is a big, fat “No!” If the sidewalls are damaged, that’s the end of the journey for any tire. Avoid committing this mistake if you want to remain on good terms with the police.
Parts of A Tire
Before diving into the legal side of sidewall damage repair, let us take a look at the overall structure of a car tire.
You may think of a tire as a single piece of circular rubber, but its complexities go far beyond that. Similar to a vehicle, tires are also made up of multiple components, which play different roles to keep you safely attached to the road.
The main components of a tire are:
- Tire Beads
- Bead Filler
- Radial Cord Body
- Inner Tire Liner
- Tire Tread
Tire Beads
The tires have to be attached to the rim to support the weight of your car, This is where the tire beads come in. They are the innermost part of the tire, and keep the tire from sliding off while in motion. Tire beads are made out of wounded high tensile steel wires coated in either brass, copper, or bronze, which are then encapsulated in a rubber coating.
Bead Filler
Bead filler keeps the tire’s sidewalls stable with its dense and stiff construction. As the name suggests, bead filler takes the form of a rubber compound, which is filled into the tire’s beads. Bead filler also has an impact on overall tire performance.
Radial Cord Body
Did you know that the weight of cars keeps going up year by year? The average weight of a car in 2023 exceeds 4000 pounds. To support all this weight, modern tires have to be stronger than ever.
Providing this strength is one main responsibility of the radial cord body. It’s made up of body piles, which are rubber-coated polyester fabric cords.
In addition to strengthening the tires, the radial cord body also transfers cornering forces from the tire tread to the wheels, which ensures the safety of the passengers as well as tire longevity.
We can categorize tires into different types depending on how the cords are laid. Some common types include radials, belted bias tires, and bias ply tires.
Inner Tire Liner
In the olden days, tires had tubes inside which kept them inflated. Nowadays, these have been replaced by the inner liner. The inner liner works in conjunction with the tire beads and bead filler to keep the air from escaping to the outside.
Tire Tread
Apart from the sidewalls, which we’ll take a look at in the next section, the tread is perhaps one of the most important parts of a tire. The tread directly comes into contact with the road surface and should provide sufficient grip, be it on asphalt, mud, sand, or snow.
Now that we have all the bases covered let us focus our attention on the sidewalls.
Importance of the Tire Sidewall
The tire sidewalls span from the tread to the bead, acting as a shield for the radial cord body, which makes up the tire’s internals. It is safe to say that the sidewall keeps all the components of a tire in place. The sidewalls also prevent debris from impacting the tire’s internals, which can result in punctures.
The sidewalls also display all the important details about a tire, like the tire size, rating, size, and the brand name of the manufacturer. They use a combination of numbers and letters to convey this information.
Let’s take P235/40/R16 70P as an example.
- Starting from the beginning, the letter P identifies the metric of the tire. In this case, it shows that the tire is a passenger tire.
- Now, let’s move on to 235. This number sequence conveys the sidewall-to-sidewall width of the tire, otherwise known as the tire section width. Frankly, this measurement tells how big the tires are. Here, the tires are 235 mm wide.
- Next is the tire profile, or aspect ratio. It compares the tire section height with the section width and is indicated as a percentage. In this example, the tire’s section height is 40% of its width.
- R stands for “Radial”, giving a hint at its construction. Depending on the type of tire, you’ll find other letters like B and D here too.
- Can you guess what the 16 stands for? If you guessed “wheel diameter”, pat yourself on the back. The bigger the wheel-and-tire setup you go for, the bigger this number will be.
- Finally, let’s look into what 70P stands for. This combination at the end indicates the load index and speed rating of the tire. The load index shows the maximum weight a tire can support when inflated, while the speed rating shows how fast it can go. Pay close attention to both these details, as they can save you from dangerous situations which will arise if you exceed these limitations.
After considering all these factors, you can understand the important role tire sidewalls play when it comes to safety. So, is it legal to patch them when some damage happens? Follow along and find out!
The Legality of Patching Tires On The Sidewall
As we mentioned earlier, modern-day tires are more durable than ever. They can take considerable damage before eventually giving way. How strong your tires may be, we never advise driving with a damaged tire, even at low speeds. A damaged tire can lose air or burst at any time, which is a huge risk to your health and safety.
However, some punctures can be patched if they are at the center of the tread. So, does this mean you should go ahead and patch that puncture on your sidewall?
Simply put, you should never try to patch any damage if it is in the center region of the sidewall. Doing so may result in a blowout, spelling disaster for you and your vehicle. In addition, this can get in trouble with law enforcement as well.
It is a good idea to refrain from patching damage which is closer than 12 mm (0.5 inches) to the sidewalls. However, we recommend checking documentation from the tire’s manufacturer before doing so, as this limit may vary between tire manufacturers.
Preventive Maintenance Tips To Avoid Tire Sidewall Damage
Sidewall damage pretty much spells the end, even for a brand-new tire. So, it is important to take care of them on every occasion.
Here are some tips to ensure sidewall longevity.
- Take Care When Parking
- Inflate Tires Properly
- Avoid Potholes
- Regular Maintenance
Take Care When Parking
Brushing against curbs when parking is one of the most common ways people ruin their sidewalls. Frequent damages like this take a toll on the sidewalls as well as the other components of the tire. So, we recommend brushing up on your parallel parking skills if you want to make your tires last for a while.
Inflate Tires Properly
For tires to serve reliably throughout their service life, adequate air pressure is a must. Ideally, the air pressure inside each tire should be between 32 – 35 psi.
When the tires are over or under-inflated, it puts pressure on the sidewalls, which results in excessive wear and damage. We recommend checking the tire pressure once a month to prevent this.
Avoid Potholes
Potholes are well-known killers of tire sidewalls. In addition to ruining the tires, hitting potholes lead to a vast array of other issues, such as bent wheels, suspension damage, steering problems, and even engine damage.
Make sure to keep an eye out for these nasty holes, especially if you regularly commute on country roads. The extra vigilance will reward you with long tire life, as well as less overall wear and tear on your vehicle.
Regular Maintenance
Just like the rest of your car, the tires also need some TLC from time to time. Dirt, debris, and oil on the tires may result in damage to the overall structure as well as the sidewalls. Keep this in mind the next time you drive over an oil patch on the highway.
There you have it, a comprehensive look at the legality of patching tires on the sidewalls. Being stranded on the side of the highway with some sidewall damage is not something we wish upon even our worst enemies. So, make sure to follow the aforementioned tips the next time you head out for a drive.
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