Understanding your tyre

27/09/2023

Reading your tyre

A truck tyre’s sidewall markings tell everything about that tyre. They describe exactly the size of the tyre, its construction and its performance limits. Much of this is statutory information and has to meet international requirements.

 

In Europe, it is the European ECE-R54 regulations which are relevant and all tyres for commercial vehicles operating within a speed range of 80 – 130 km/h carry a ‘Service Description’ which is placed close to the tyre size marking.

 

Goodyear trailer tyres produced for the Europe, Middle East and Africa carry the “FRT” marking on their sidewalls. “FRT” stands for “Free Rolling Tyre” and is a legal marking according to the UNECE Regulation No. 54, which indicates that the tyre is specifically designed and intended for the equipment of trailer axles and axles of motor vehicles other than front steering and all drive axles.

Reading and understanding tyre markings

The position of the major tyre markings are as shown

  1. 1. Tyre Section width (mm or inches)
  2. 2. Aspect ratio SH / SD Radial construction
  3. 3. (R=Radial)
  4. 4. Rim Diameter (inches)
  5. 5. Load Index (Max. load per tyre - single tyre)
  6. 6. Load Index (Max. load per tyre - dual mounted)
  7. 7. Speed Symbol
  8. 8. Alternative load indices when used with alternative speed
  9. 9. TWI - Tread Wear Indicator
  10. 10. ECE Homologation number
  11. 11. Date code (week, year)
  12. 12. DOT Manufacturing Code
  13. 13. Noise number - indicates that the tyre conforms to ECE noise regulations
Goodyear tyre width marking

Tyre width

The width of your tyre, in millimeters, measured from sidewall to sidewall.

Goodyear tyre aspect ratio

Aspect ratio

This is the ratio of the tyre’s cross-section to its width, expressed as a percentage. An aspect ratio of 70, for example, indicates that the tyre’s height is 70% of its width.

Goodyear tyre wheel diameter

Wheel diameter

The diameter (height) of the wheel in inches.

Goodyear tyre load index

Load index

Your tyre’s load index tells you its maximum carrying capacity. It’s important to choose a replacement tyre that fits with your manufacturer’s recommendations.

Load ratings and speed ratings should be looked at together when you choose a tyre. You’ll find the load rating of your current tyre on the sidewall, just beside the diameter.

We aim for our publications to be as accurate as possible, but they do not constitute legal or technical or professional advice. Please seek professional advice before taking any action. 

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