Tyre Size – What you should know

Each tyre contains a coding and at a first glance it may look quite confusing. To help you understand what the coding means Event Tyres have produced the following summary.

The tyre size is made up of several parts, the width of the tyre in millimetres, the profile (percentage of the width), the diameter of the inner rim and the load & speed ratings. So in this example;

tyre size guide

225/45 17R 91Y

The width (A) is 225mm
The profile is 45% (B = 101mm)
The diameter (C) is 17 the R stands for Radial. If there is no letter then it is a cross ply tyre.
The 91 is the load rating and the Y is the speed rating

Tyre Speed rating

The speed rating is the maximum speed for the tyre. The table below shows you what each letter represents.

Code mph
K 68
L 75
M 81
N 87
P 94
Q 100
R 106
S 112
T 118
U 124
H 130
V 149
Z Over 149
W 168
(W) Over 168
Y 186
(Y) Over 186