In order to find the right tyre for your car, it is necessary to know the 4 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. 255/35 means that 35 is 35% of 255).
The letters R or D indicate the tyre type – radial or diagonal. The diameter of the wheel in inches is given last.