Every commercial vehicle tyre carries a standardised set of markings on its sidewall that communicate important technical information about its dimensions, construction, and performance capabilities. Being able to read and interpret these markings helps fleet managers verify that the correct tyre has been supplied and confirm it is appropriate for the vehicle and its operating conditions.
The primary size designation appears as a group such as 315/80 R22.5. The first number is the tyre section width in millimetres. The second number is the aspect ratio — the sidewall height expressed as a percentage of section width. The letter R indicates radial construction, which is standard for commercial vehicle tyres. The final number is the rim diameter in inches.
Following the size code you will find a load index and speed rating designation. The load index number represents the maximum weight each tyre can carry at rated pressure. The speed rating letter indicates the maximum sustained speed at which the tyre may carry its full rated load. Both values must be appropriate for the vehicle's plated weight and maximum operating speed.
Additional markings indicate suitability for re-grooving (RG), winter capability (M+S marking or the three-peak mountain snowflake symbol), and the tyre's date of manufacture. The production date appears as a four-digit code — for example, 1524 indicates manufacture in the 15th week of 2024. Checking this date is useful when inspecting tyres that have been in storage, as age-related compound degradation can affect safety.
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