How to read a tyre
The following information, located on the sidewall of the tyre, guarantees that your service provider will deliver the correct tyres for your vehicle.
Size markings indicate the different tyre types, and should be treated the same as any vehicle part number. Ensure that your vehicle is equipped with the precise size markings listed in the vehicle handbook or indicated as an approved alternative.
In accordance with the European regulation ECE-R54, all commercial vehicle tyres are marked with a service description located near to the tyre size marking. This consists of a code indicating load and speed limits and includes a load index for single and dual tyre fitment as well as a speed symbol (e.g. 156/150 L). An additional marking may be used to show the corresponding tyre loads for an alternative higher speed. This marking will be placed in a circle.
|Section width in inches||R-radial in inches||Rim diameter||Load index (single/ dual mounted)||Speed symbol|
|Section witdth in mm||Aspect ratio||R-radial in inches||Rim diameter||Load index (single/ dual mounted)||Speed symbol|
|Section witdth in mm||Aspect ratio||R-radial in inches||Rim diameter||Load index (single mounted)||Speed symbol|
Where the tyre markings are positioned
- Tyre Section width (mm or inches)
- Aspect ratio S.H./S.W.
- Radial construction (R=radial)
- Rim diameter (inches)
- Load index (max. load per tyre – single tyre)
- Load index (max. load per tyre – dual mounted)
- Speed symbol
- Alternative load indices when used with alternative speed
- TWI = tread wear indicator
- ECE homologation number
- Date code (week, year)
- DOT manufacturing code
- Noise number, indicating that the tyre conforms to ECE noise regulations
Safety regulations for USA and Canada
In accordance with the US safety regulation MVSS 109 for car tyres and 119 for truck tyres, the maximum load of the tyre in pounds (LBS) and its corresponding air pressure in pounds per square inch (PSI) must be shown on the tyre. Additionally, the tyre must be marked D.O.T. (Department of Transportation), ensuring that it conforms to all valid regulations in these countries.