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

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. 


Service description

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. 


Size definitions

Section width in inches  R-radial in inchesRim diameterLoad index (single/ dual mounted)Speed symbol
295 /80R22.5152/148M
Section witdth in mmAspect ratioR-radial in inchesRim diameterLoad index (single/ dual mounted)Speed symbol
365 /80R20.0160J
Section witdth in mmAspect ratioR-radial in inchesRim diameterLoad index (single mounted)Speed symbol


Where the tyre markings are positioned


  1. Tyre Section width (mm or inches)
  2. Aspect ratio S.H./S.W.
  3. Radial construction (R=radial)
  4. Rim diameter (inches)
  5. Load index (max. load per tyre – single tyre)
  6. Load index (max. load per tyre – dual mounted)
  7. Speed symbol
  8. Alternative load indices when used with alternative speed
  9. TWI = tread wear indicator
  10. ECE homologation number
  11. Date code (week, year)
  12. DOT manufacturing code
  13. 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.

Fleet First is a service from Goodyear Dunlop