Tyre Sidewall Explained

SidewallYou will find the size of a tyre on its sidewall. With a quick explanation as to what the different numbers mean, you will see that it is very quick and very easy to find out a tyre's size.

Looking at the following image, you will see the mixture of letters and numbers: "205 55 R16 91 W"

We have broken down each section in the following table, explaining what each number/letter means:

Sidewell Marking Explanation
205 Width of the tyre in millimetres

Height of the tyre sidewall as a percentage of the width. In this case 55% of 205mm. Also know as the aspect ratio.

R Radial Construction

The diameter of the tyre's inner rim in inches


Load Rating of the Tyre. In this case its 615kg


Speed Rating. Indicates the maximum speed for the tyre when at full load. In this case 168 mph.


ECE type approval mark, which demonstrates the tyre has been tested as high quality by the European Regulatory Authorities. All Tyres sold by Blackcircles.com carry this mark.

If you still have questions regarding your tyre size, do not hesitate in calling our team of tyre experts on 0845 620 2000.