Tyre Size Guide

Each tyre contains a code and at first glance it may be confusing for drivers as to what the collection of numbers and letters mean. To help you understand the coding, we've provided an explanation below which provides all the details that you will need.

What Size Are My Tyres?

A tyre size is made up of several parts and is considered in millimetres. The width, the profile (percentage of the width), the diameter of the inner rim, and the load and speed ratings.

How to Check Tyre Size

To check your tyre size, it’s simply a case of looking at the tyre which is fitted to your vehicle. You’ll find the details along the sidewall of your tyre as a series of numbers and letters.

What do Tyre Sizes Mean?

Below is a typical example for how this is written on the side of a tyre, along with what they mean:

tyre size guide

Example: 225/45 17R 91Y

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

Tyre Speed Rating

The speed rating is the maximum speed for the tyre. The table below displays what each letter represents:

Codemph
A-J62
K68
L75
M81
N87
P94
Q100
R106
S112
T118
U124
H130
V149
ZOver 149
W168
(W)Over 168
Y186
(Y)Over 186

Our Service

If you have any further questions about tyre sizes or would like to book a mobile tyre fitting, please make your order online. You can also get in touch with us on 0800 810 0972.

We’re up to 40% cheaper than the High Street and we’ll drive directly to a location of your choice to provide you with a free fitting.

Book a fitting online now