How to read tyre size from the tyre sidewall

If you have ever looked at a tyre, you probably will have noticed that the side wall has a mixture of letters and numbers embossed on it. It can be easy to overlook them, but they are important as they represent all of the vital information about that tyre which is required for when you need to replace it.

Each number and letter relates to an aspect of the tyre itself or its potential performance. For example:

A car has 165/60 R 15 82 T on its side wall.

165 – This is the width of the treaded area in millimetres

60 – This is the percentage height of the sidewall, known as the aspect ratio.

R – Radial construction (All modern tyres are constructed in this way, only tyres for classic cars will not be radial)

15 – The size of the wheel (aka rim) that that the tyre was manufactured to fit in Inches

T – The maximum speed rating (this is part of a standardised chart)

If you were replacing your tyre, then you would need to quote this information to the garage or tyre provider.