Are you looking for the right tyre size for your vehicle? You are on the right page – in this blog, we are explaining all of the unique tyre markings and their meaning, and showing you what do they look like when located on the tyre’s sidewall.
Tyre Sidewall Markings Explained
There are several tyre markings that you can find on each tyre. Even though they look complex, they are fairly easy to understand once you know what each of these markings refers to. For instance, the tyre might be marked with the designation 215/60R16, where:
- “215” refers to the width of the tyre, which in this case is 215 millimeters,
- “60” refers to the nominal aspect ratio of 60%, which is the ratio of the height of the tyre’s sidewall to the tyre width (calculated as the height of the tyre section divided by its width), and
- “R16” where the number is is the rim diameter, determined diagonally from rim edge to rim edge (in inches), and the “R” refers to radial tyres, which are the most common tyres found on the road nowadays. Other examples are “B” for bias-ply tyres and “D” for diagonally constructed tyres.
Next are the indexes, where we have the:
- Load Index, which spans from 75 to 105 on passenger tyres. Here, each numeric value corresponds to a specific load capacity, indicating the maximum load a tyre may be subjected to. Make sure to choose wisely and stay within the load index as it directly impacts the vehicle’s safety.
- Speed Index, which is the maximum permissible speed at which you may drive the car supported by the tyres. This index is a combination of a number followed by a letter. For instance, the index “91V” indicates a maximum speed of 240km/h (based on a table), and the letter “V” is an alphabetical index, by which A indicates the lowest and Y the highest speed class.
- DOT number, which provides information about the manufacturer plant, tyre size, brand, and tyre age. For instance, the marking “DOT 26/21” shows that the tyre was manufactured in the 26th week of year 2021.
Other Tyre Markings
In many cases, there may be are additional tyre markings that show more information about the tyre. For instance, the marking “SSR” means that the tyre is a self-supporting run-flat model, and can continue to be used in the event of pressure loss thanks to its reinforced wall structure.
You can also identify a directional tread designation, which marks tyres with a specific tread and an arrow together with the terms “rotation,” “direction of rotation,” or just “direction,” indicating the direction in which the tyre must be mounted. The rotational direction of tyres is important if you are planning to rotate your tyres, which could maximize their lifespan. Rotating them as per the manufacturer’s advice is essential for the best performance.
Markings like “tubeless” or “TL” indicate that the tyre has no inner tube, while “run-flat” tyres are a special form of tubeless tyres with emergency operation properties (they can still be driven in the event of damage). Many manufacturers use different markings to mark their run-flat tyres, with “SSR” being the most prominent and relating to self-supporting run-flat.
Similarly, “M+S” may describe that the tyre is suitable for mud and snow conditions, and “OE” shows that the tyre is an Original Equipment tyre for specific vehicles. “Alpine” is also common among tyre markings, which is a uniform symbol for all winter tyres manufactured from 1 January 2018.
Lastly, tyres have a wear indicator which is labeled with the letters “TWI” meaning Tread Wear Indicator, a sign that is usually stamped in several places of the tyre, making it easy to see the tread wear and know when too much tread has worn off and the tyre may no longer be driven.
