In order to find the right tyre for your car, it is necessary to know the four values that make up the tyre size.
Width – it is a key value which is at the beginning of the sequence of characters and is expressed in millimetres (e.g. 155/, 165/, 175/). The tyre width is the distance from the extreme point of the outer sidewall and the furthest point of the inner sidewall.
The profile of a tyre is given as a percentage and indicates the height, i.e. the percentage ratio of the height of the tyre sidewall to its width (e.g. 155/80 means that 80 is 80% of 155).
The letters R or D indicate the tyre type – radial or diagonal.
13 - the last value given is the diameter of the rim given in inches.