TRA code and Star rating

According to the internationally standardised TRA codes, a TRA code always consists of a letter that is followed by a number, although this number is sometimes also followed by another letter. The first letter indicates for which type of machine the tyre can be used. The next digit indicates the tyre's tread depth. If this is followed by a third digit, it will say something about the tyre's pattern and the purpose for which the tyre is best suited.

The TRA code is recognised as an international benchmark and is validated by the ISO (International Standard Organisation), the ETRTO (European Tyre and Rim Organisation), the TRA (Tyre and Rim Association) and the JATMA (Japan Automobile Tyre Manufacturers Association). These organisations have defined four types of OTR tyres - based on their purpose - and industrial tyres. The designated category can be found on the side of the tyre. The types in question are found 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 represents 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 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.

Differences between E and L tyres E and L tyres have a different load/speed index. This is something you should bear in mind when making your choice. In addition, L tyres cannot exceed a cycle of e.g. 200 metres, otherwise too much heat is generated and they become way too hot. In contrast, E tyres are often heat resistant and can deal with heat more effectively. Some tyres in the OTR segment feature an E code as well as an L code (e.g. E3/L3). They are also referred to as ‘multi-star tyres’ and are ideal for loading and transport vehicles. This means graders have their own specific tyres, but can also feature both E and L tyres.

When should you use each tread depth? You can opt for E3 or E4 tyres when performing transport activities. E5 tyres do not exist because this tread depth and high speed would cause a lot of heat to be produced, which would become too much for the tyre to deal with. When performing loading activities, you can choose between L3, L4 and L5 tyres. The area in which tyres are used determines the tread depth you should be using. For example, if you are using a dump truck in a quarry, we recommend an E4 pattern for extra protection. If you use L tyres, but the cycle is too long for an L5 tyre, you should use an L4 tyre so a longer cycle is possible. The surface also plays a major role in the type of tyre you should choose. For example, tyres with 100% tread depth, and a traction pattern, are used for sand and asphalt surfaces. However, if the surface is more aggressive (stones/rocks), people often prefer tyres with 150% or 250% tread, and a more closed pattern.

Overview of TRA codes Code Profile Use

C1 Smooth Compactor

E1 Ribbed Earthmover, transport

E2 Traction Earthmover, transport

E3 Rock Earthmover, transport

E4 Rock (deep tread) Earthmover, transport

E7 Flotation Earthmover, transport

G1 Ribbed Grader

G2 Traction Grader

G3 Rock Grader

G4 Rock (deep tread) Grader

G5 Rock (very deep tread) Grader

L2 Traction Loader, dozer

L3 Rock Loader, dozer

L4 Rock (deep tread) Loader, dozer

L5 Rock (very deep tread) Loader, dozer

L3S Smooth Loader, dozer

L4S Smooth (deep tread) Loader, dozer

L5S Smooth (very deep tread) Loader, dozer

Star rating indicates load capacity The number of stars on an OTR tyre indicates the tyre's load capacity. This is also linked to the TRA code. Both these factors jointly determine the purpose for which tyres can be used. Stars Machine/purpose

1* / 2* / 3* (strength) Loader and bulldozer (L)

2* / 4* (speed) Transport (E)

3* (combination) High speed/Industry (IND)

1* / 2* (strength) Grader (G)