Not sure what the sidewall on your tyre actually does? This quick guide explains what the tyre sidewall is, how to understand its markings, and how to recognise early signs of damage. Learn how these simple checks can keep your tyres performing safely and extend their lifespan.
We don’t need to tell UK drivers that vehicle maintenance can be a bit of a minefield. From keeping fuel topped up, checking tyre tread, and ensuring that your tyres are well suited to both the season and the road surface you’re driving on, vehicle maintenance is critical for both safety on the road and optimum efficiency and comfort.
Of course, when it comes to tyre maintenance in particular, there are several parts and areas of the tyre that you need to be familiar with. One of the parts of a tyre is the sidewall – the stretch of rubber between the outside edge and the beading which connects the rubber with the wheel rim.
But what exactly does the sidewall do? In this blog, our team of tyre experts explain the purpose of the sidewall and how to interpret the various markings on the surface.
What is the Tyre Sidewall?
The tyre sidewall is the flat section of the tyre which stretches from the outer edge of the wheel rim right out to the tread of the tyre.
When you kneel down and position yourself so that your head is level with the tyre, the sidewall is the bit you see most clearly – covered with markings, letters and numbers. These markings are what drivers use to ensure they have the right tyre to match the vehicle in terms of size and season, with more on the markings in the next section.
But the sidewall doesn’t just translate important information about the tyre itself.
The sidewall is also one of the first places to check if you are worried about tyre damage. Cracks, bulges, and cuts are all clearly visible on the sidewall of a tyre and can be indicators that something is wrong with the tyre and its structure. If you can see signs of damage on the sidewall, the chances are that the structural integrity of the tyre has been compromised – making the tyre unpredictable and subject to potential tyre failure or a lack of control over the vehicle.
Tyre Sidewall Markings: Interpreting the Various Markings
Before we look at tyre sidewall damage, let’s look at some of the markings and equations which cover the surface of the sidewall.
The sidewall is where you will find information about the tyre size, load rating, speed rating, manufacturing, seasonal design, and more. The tyre size equation is the marking that drivers need to be most at ease and familiar with, as it’s this that enables you to ensure any future tyres you buy will fit the vehicle.
Tyre Size Example
215 \ 55 \ R16 97V
Each set of numbers on this example relates to a different specification for that tyre…
- 215 – Tyre Width. This is width of the tyre, as measured in millimetres.
- 55 – Tyre Profile. This is the height of the sidewall as a percentage of the width.
- R – Construction. This tells you that the tyre is made of Radial construction.
- 16 – Tyre Diameter. The inside rim of the tyre in inches.
- 97 – Load Rating. How much load and vehicle weight the tyre is designed to take.
- V – Speed Rating. This is the maximum speed rating for the tyre.
This gives you some idea as to how to read the main equation you’ll see on a tyre sidewall. Using this information, you can ensure that all future tyre purchases are suitable for your vehicle, facilitating fuel efficiency, a smooth drive, and maximum road safety.
Diagnosing Tyre Sidewall Damage
Damage is something we mentioned earlier in this blog, but what we haven’t covered is what to do when you see signs of cracking, bulging, bubbling, or splitting in the tyre sidewall.
When you notice damage on the exterior of the tyre sidewall, this means that damage has occurred, and the tyre needs to be replaced. Though there may be no imminent or immediate danger in terms of loss of control or tyre failure, it’s important to note that once damage has occurred, this will only continue to worsen.
Something as small as hitting a pothole or driving over an obstacle on the road surface can cause undue damage to a tyre which is already compromised – meaning that once you spot the signs of damage outlined above, you should replace the tyre before the damage gets worse.
