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Tyre Size Guide

There are six main pieces of information that dictate the specification of a tyre. This information is clearly marked on the side of each tyre. It is not recommended to have tyres with a lower speed rating or load capacity than the manufacturers recommended specification which can usually be found in your vehicle handbook.

tyre-identification

Tyre Width
This is the nominal sectional width of the tyre. In the above diagram this would be 205mm

Tyre profile
Stated as an aspect ratio representing the height of the sidewall as a percentage of the sectional width. In the above diagram this would be 55%

Radial Construction
This denotes the construction type of the tyre. Most tyres today are Radial (R) construction. Less common types are Bias Belt (B) and Diagonal (D).

Tyre size
This is the diameter of the tyre's inner rim in inches. In the diagram above the tyre size is 16".

Load Rating
The load rating is a numerical code which denotes the maximum load a tyre can carry at the speed indicated by its speed symbol. It is not recommended to have tyres with a lower load capacity than the manufacturers recommended specification which can usually be found in your vehicle handbook. For a chart of tyre load rating values, see our Tyre Load Chart.

Speed Rating
The speed symbol is an alphabetical code which indicates the speed at which the tyre can carry the load corresponding with its load index. It is not recommended to have tyres with a lower speed rating than the manufacturers recommended specification which can usually be found in your vehicle handbook. For a chart of tyre speed rating values, see our Tyre Speed Chart.