Understand Your Tyre Markings

03 October 2019 / Lindleys Autocentres

Understanding your tyre markings can be a difficult task, especially if you are new to the road. But don’t worry, whatever stage of driving you are at - old or new - we have put together a useful guide on how to read your tyre markings. 

In this blog post we will cover:

  • Reading your tyre markings

  • Tyre speed rating

Reading your tyre markings

The markings on the tyre include words, letters, symbols and brand name. These also refer to the tyre size.  Each attribute has its own purpose, providing information regarding the tyre width, sidewall height, diameter, tread pattern, local index and speed rating. These are discussed individually below:

Tyre Markings

  • 235 - This is the tyre width in mm. In this example, the tyre width would be 235mm

  • 55 -  The aspect ratio of the tyre - the aspect ration of the sidewall expressed as a percentage

  • R -  ‘R’ indicates it is a ‘radial’ construction

  • 17 - The inside diameter of the tyre. In this example, this would be 17”

  • 99 - Load index

  • W - speed rating

Tyre speed rating

A tyre speed rating refers to the maximum speed that the tyre is legally approved for. This information can be found on the side of tyre like the example image showed above. The tyre speed rating can be found at the end of the tyre represented by a letter and followed by a number.  On the example provided above, this is 99W. 


It is important to be aware of your tyres speed rating as this will determine the maximum speed your tyre is capable of safely reaching. 


When choosing tyres, it is important that your tyre speed rating matches the official top speed of your car. Fitting lower-speed-rated tyres could affect your car insurance.  


To find the correct tyres, with the correct speed rating for your car, use our vehicle registration number tyre finder on our website which will automatically choose the correct tyres for your car.  Alternatively, contact a friendly member of our team who will be happy to help you choose the correct tyres for your vehicle. 

Further reading:

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