Let's take the tyre size 205/55R16 for example. 205 is the width of the tyre in millimetres – fairly straight forward. However, the 55 is the ratio of the tyre's width to the tyre's height. So it means that the aspect ratio or Tyre Profile is 55% of the 205mm width.
You 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:
|Width of the tyre in millimetres.
Height of the tyre sidewall as a percentage of the width. In this case 55% of 205mm. Also known as the aspect ratio.
|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 270 km/h.