A tire’s sidewall provides your vehicle with stability while protecting the tire’s inner components, but it’s often overlooked in terms of maintenance and as a source of valuable information.
We’ve come up with this simplified introduction that lets you in on everything you need to know about tire sidewalls.
What Is A Tire Sidewall?
A tire’s sidewall is the area from the tread to the bead of the tire, the latter being where the rubber connects with the rest of the wheel. It forms the protective shield for the radial cord body or body plies directly underneath it. On a run flat tire, the sidewall is reinforced with steel that allows it to remain rigid so it can support the vehicle for a short distance after it gets a puncture or loses pressure in another way.
To learn everything you need to know about sidewalls, including what information is printed on it, how to read it, and more, read on!
What Is The Function Of a Tire Sidewall?
A sidewall keeps the internal components of the tire such as the belt plies, radial cord body, and liners in place.
Sidewalls also provide lateral stability for the vehicle when the tires are uniformly inflated.
It also contains valuable information about the tire, a function we’ll delve further into below.
Does The Sidewall Of A Tire Matter?
Aside from the protection your sidewall provides for the tire’s internal components, it also significantly affects how your vehicle handles.
Your sidewall’s stiffness determines the smoothness of your ride and how much control you have when driving.
A tire with a hard sidewall is sturdy and therefore easier to control, but it provides a rougher ride because it doesn’t absorb shocks on the road.
Soft sidewalls make your tires harder to control, but they take in the shocks and bumps on the road better, so the ride is smoother.
For this reason, race drivers prefer harder sidewalls for improved control, while everyday drivers prefer softer sidewalls for a comfortable ride.
What Information Is On The Sidewall Of A Tire?
A sidewall contains valuable information about the tire that helps you determine when and where to use it as well as its limits.
It lets you know your tire’s intended use – e.g. passenger (P), light truck (LT), special trailer (ST) – , load capacity (could be in number of passengers or weight in pounds or kilograms depending on the country) size (tread width, aspect ratio, bead diameter), speed rating and the serial number as required by the Department of Transport (DOT).
What Is a Tire Sidewall Rating?
When reading the information on a sidewall, you will see its speed rating, i.e. the highest speed it can sustain under the manufacturer’s recommended load capacity.
These ratings are represented by letters A to Z, where A is the worst rating and Z is the best.
A Z rating means the tire can sustain speeds of more than 149 mph or about 240 km/h.
What Is OWL On Tire Sidewall?
On a tire sidewall, OWL stands for outlined white letters, and it literally means letters printed on the sidewall that are white and outlined.
These letters usually spell out the tire manufacturer’s name, logo, or both, and they’re popular for people who want to show off a custom job because this design isn’t commonly found on stock tires.
What Do The Acronyms On Sidewall Mean?
There are some other common acronyms you should know when reading the sidewall, and some of them are also cosmetic, but others denote functional specifications of the tire.
Apart from the ones mentioned so far, you might come across RWL (raised white letters), ORWL (outlined raised white letters), XL (extra load capacity), XNW (extra narrow white width), REIN (reinforced), and VSB (vertical serrated band).
W, WW, and WSE mean whitewall or white sidewall for a sidewall with a stripe or entire sidewall of white rubber such as the one on classics, while B, BW, BLK, and BSW mean blackwall or black sidewall.
What Is Tire Sidewall Damage?
Sidewall tire damage is exactly what the name suggests: damage to the side or walls of your tires such as missing chunks, abrasions, bulges, gashes, holes, and more.
Can A Tire Sidewall Be Repaired?
You can repair a damaged sidewall using patches, plugs, and sealants.
However, you shouldn’t make a habit out of it i.e. you should try to avoid repairing the sidewall more than once because it’s often difficult to determine whether the internal components have been affected.
What Is Tire Sidewall Height?
A sidewall’s height is the distance from the rim to the tread and can be determined by calculating the difference between the tire’s inner and outer diameters.
What Causes A Tire Sidewall Blowout?
Your sidewall could blow out if you underinflate the tires because they flex more from lack of pressure and heat building up inside them over time.
They can also blow out when you overload the vehicle beyond the manufacturer’s recommended weight capacity as indicated on the sidewall itself.
They can also blow out as a result of prior damage, uneven wear on the tires, or plain manufacturer defects, so you should always get them checked whenever you’re getting any car service.
What Causes A Tire Sidewall To Bubble?
If you notice a bubble on the sidewall of your tire, it means that its inner liner has sustained damage and is leaking air.
This damage could be the result of impact in an accident or manufacturer defects and is very likely to cause a blowout so, again, you should inspect your tires regularly.
To know more about tires, you can also read our posts on cracks in the tire sidewall, why tires are so expensive, and what hydroplaning is.
Your tire’s sidewalls are found between the tread and where the tire connects to the metal part of the wheel.
It provides lateral stability for your vehicle while protecting and holding in place the internal parts like liners and belts.
On run flat tires, the sidewalls are enforced, usually with steel, so that you can drive to a service station in case of a puncture.
There’s a lot of information printed on the sidewall that lets you know about the tire’s specifications, including size, load capacity, speed rating and more.
You need to pay keen attention to this information for proper maintenance and to avoid overworking your tire so it lasts as long as possible.
It could get damaged through impact, wear or manufacturer defects, and the issues could show up as missing chunks, bubbles, gashes, abrasions, loss of pressure and more.
You can fix up a sidewall using a patch, plug or sealant but if you can replace the whole tire, you should do that instead because a breached sidewall is more likely to blow out even if you repair it.
Moreover, it’s easy to determine when the sidewall itself has sustained damage but it’s harder to spot the same in the internal parts so it’s safer to replace the entire thing.
You should have your sidewalls inspected whenever you take your car in for service so you catch these and other issues before they get more serious and pose a greater risk.