Understanding your tyre

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.

The position of the major tyre markings are as shown

1. Tyre Section width (mm or inches)

2. Aspect ratio SH / SD Radial construction

3. (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 - indicates that the tyre conforms to ECE noise regulations

Tyre width

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

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.

Wheel diameter

The diameter (height) of the wheel in inches.

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.

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