The TRA code is an industry rating defining a tyre’s ability to deliver specific characters. It is recognized as an international benchmark and is validated by the following standardization organisations: -

  1. ISO (International Standard Organisation),
  2. ETRTO (European Tyre and Rim Organisation),
  3. TRA (Tyre and Rim Association),
  4. JATMA (Japan Automobile Tyre Manufacturers Association).

Types of OTR tyres

The internationally standardized TRA code can be used to select appropriate OTR tyres for all machines.

There are four types of OTR and industrial tyres - based on their application. The designated category can be found on the sidewall of the tyre. The types are listed below; and are reflected in the first letter(s) of the TRA code:

  • C = Compactor (road-building machines and steam rollers),
  • L = Loader/Dozer,
  • G = Grader,
  • E = Earthmoving (transport; scrapers, articulated and rigid dump trucks),
  • IND = Industrial (port).

The following digit further define the tyres by representing the tread depth: -

  • 2/3 stands for 100% tread depth
  • 4 stands for 150% tread depth
  • 5 stands for 250% tread depth

Finally, if this is followed by another letter, this will say something about the tyre's tread pattern: -

  • T stands for ‘Traction’
    These tyres have a fairly open pattern, which offers very good traction. 
  • R stands for ‘Rock’
    These tyres have a more closed pattern, which means they offer less traction, but are less susceptible to cuts. 
  • S stands for ‘Smooth’
    This means the tyres do not have a pattern (also referred to as slicks). These tyres offer little to no traction, but offer very high resistance against cuts.