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This information is presented as tyre signs and symbols – which can be confusing if you don’t know what you’re looking for! Take a look at this helpful introduction to tyre markings and learn what your tyre is telling you.
The side of your tyres provide a good amount of information about their size, specification, use and safety standards. Numbers, signs and symbols may appear confusing at first but are easy to understand once you know the 'code'. Here's some info' to help you understand what you have, and what you may need.
TYRE LABELLING
Tyre Size
On our example you can see a string of numbers (255/55 R16), which most people are familiar with if they've ever ordered tyres before. These tell you about the size of your tyre. It is important that you fit the correct size tyre to you car, so it's always a good idea to check your handbook to make sure what you currently have fitted is right for your vehicle.
255 • Width of the Tyre
In our example the number '255' tells you the width of the tyre, in millimetres, from one side wall to the other
55 • The Tyre's Aspect Ratio
This number relates to the height of the tyre wall. Rather than being measured in mm it is expressed as a percentage of the tyre's width. So on our example we can see the height of the tyre wall is 55% of its width.
R • Type of Tyre Construction
You will typical see an 'R' here, this tells you that the tyre is of a radial construction, which is how most tyres are made. Other letters you could see include ‘B’ which stands for bias belt construction and ‘D’ which is for a diagonal construction.
16 • Diameter of the Wheel
Now a measurement in inches! This next number relates to the size of the wheel rim that the tyre is to be fitted to.
OTHER SYMBOLS
The Load Index
The load index informs you of the maximum load a tyre can carry. Our example shows a load index of '105' If you look for this in the table you'll see it translates to a maximum load for this tyre of 925Kg.
The Speed Rating
Every tyre has a maximum speed for which it is suitable; relating to the maximum speed it can travel under its' maximum rated load. The speed rating of the tyre is expressed as a letter, in our example 'V'.
In the table below you can see that 'V' indicates the maximum speed for this tyre is 149 mph or 240 km/h.
WHAT ELSE?
There can be a lot of other marks and codes on a tyre. Six of the most common and useful marks are listed here.
Brand Name
Manufacturers love to put a big logo on the side! You'll always find the brand and often a tyre model number.
Pattern Name
There are a number of different patterns of tyre which will be noted on the side. Treads themselves are designed for different road conditions and driving styles. Typically they fall into one of four categories: directional, symmetrical, asymmetrical, and directional/asymmetrical (see 'Types of Tread').
Brand Name
Manufacturers love to put a big logo on the side! You'll always find the brand and often a tyre model number.
Pattern Name
There are a number of different patterns of tyre which will be noted on the side. Treads themselves are designed for different road conditions and driving styles. Typically they fall into one of four categories: directional, symmetrical, asymmetrical, and directional/asymmetrical
Country of Manufacture
The country of manufacture will be written on the sidewall
European ECE Type Approval
This indicates that the tyre has been tested and passed European safety standards. Country of manufacture and testing are not always the same. The digit following the E in the code identifies the country where the test was passed, in the case '11' is the UK.
Tread Wear Indicators
Tread wear indicators are situated in the grooves of the tyre and may be in the form of letters ‘TWI’, a logo, a solid bar or some other marking. These will only be visible when the tyre tread is close to approaching the legal minimum of 1.6mm. Not all tyres have tread wear indicators so always check yours, try the 20p test.
Date of Manufacture Code
This is a series of letters and numbers something like DOT********2020. The last four digits are the date code, this example the tyre was manufactured in the 20th week of 2020.
Country of Manufacture
The country of manufacture will be written on the sidewall
European ECE Type Approval
This indicates that the tyre has been tested and passed European safety standards. Country of manufacture and testing are not always the same. The digit following the E in the code identifies the country where the test was passed, in the case '11' is the UK. Checkout the table below if you are looking for a tyre's ECE approval code.
Types of Tread
1. Directional (unidirectional)
Directional tread is designed to move in one direction which is indicated by an arrow. The design allows for water to be displaced from the tire to avoid hydroplaning. Directional tires should be rotated front to back from the side that they are in since each tire is designed and angled to perform best on their specific side.
2. Symmetrical
Symmetrical tire tread has the same pattern across the whole tire. This type of tire is the most common and found on most non-high-performance passenger cars because it is typically quiet and long-lasting. They can be rotated in many different ways, which helps to prolong the life of the tires and makes them more versatile.
3. Asymmetrical
Asymmetrical tire tread, most commonly found on sports cars, is a bit of hybrid in that it combines a variety of tread patterns for maximum grip on both wet and dry roads. Usually, the inside and middle parts of the tire will be designed for wet and/or winter traction while the outside of the tire will have large tread blocks for maximum cornering capability on dry surfaces. To ensure that the tires are positioned correctly on the car (to maximize handling capabilities), the sidewalls are marked "outside only" and "inside only." Many different rotation patterns can be used for tires with asymmetrical tread patterns.
4. Combined: Directional/Asymmetrical
Directional/asymmetrical tire tread is the best of both worlds – it features the V-shaped pattern of the directional tread for discharging water away from the tire and the dry weather traction of the asymmetrical tread. You should follow the same rules as directional tires when it comes to rotation patterns. Vehicles equipped with different size tires on the front and rear (staggered), prohibit the ability to rotate directional/asymmetrical tires unless they are remounted.