The Tire and Rim Association service code is the cross-manufacturer system for describing OTR tyre application. The letter is the machine category. The number is tread depth, intended use, and compound family. Where the same physical tyre appears in two manufacturer databooks, the TRA code is usually the only label that's consistent.
Service codes do not specify the tyre size, load capacity, or compound type. They sit alongside those things. A 26.5R25 L-5 from Bridgestone has the same TRA code as a 26.5R25 L-5 from BKT – the codes match the application, not the maker.
| Code | Name | Description | Typical fitment |
|---|---|---|---|
| E-1 | Rib | Smooth-shoulder ribbed tread for on-highway haul vehicles. | Highway dump trucks, water carts |
| E-2 | Traction | Standard traction tread for general earthmoving. | ADTs, smaller haul trucks |
| E-3 | Rock Regular | Standard tread depth, normal-duty rock applications. | Mid-size haul trucks (90–150t) |
| E-4 | Rock Deep | Extra-deep tread (~1.5× E-3), longer life, cut resistance. | Tier-one Pilbara iron ore haul (CAT 793, Komatsu 830E, 930E) |
| E-5 | Rock Extra Deep | Maximum tread depth, extreme applications. Uncommon. | Severe rock conditions, niche fleet |
| E-7 | Flotation | Wide footprint, low ground pressure. | Soft-ground earthmoving |
| Code | Name | Description | Typical fitment |
|---|---|---|---|
| L-2 | Traction | General traction lug pattern. | Light loader, smaller dozers |
| L-3 | Rock Regular | Standard rock tread, general-purpose loader. | CAT 966–972, Volvo L150 |
| L-4 | Rock Deep | Deeper tread, longer wear, mid-tier mining and quarry. | CAT 980–988, Komatsu WA470–WA500 |
| L-5 | Rock Extra Deep | Extra-deep tread, high cut and heat resistance. The default for hard-rock and abrasive iron ore. | CAT 988–994, Komatsu WA600–WA1200 |
| L-5S | Smooth Extra Deep | Smooth tread, extra deep – underground loader applications. | Underground LHDs, dozers in fine material |
| Code | Name | Description | Typical fitment |
|---|---|---|---|
| G-1 | Rib | Smooth-shoulder ribbed pattern, on-haul road grading. | Civil road graders, highway maintenance |
| G-2 | Traction | General-purpose traction pattern for grader applications. | CAT 14M, 16M, 24M; Komatsu GD-series |
| G-3 | Rock | Deeper tread for off-road grading. | Quarry graders, rough-ground civil |
| Code | Name | Description | Typical fitment |
|---|---|---|---|
| C-1 | Smooth | Smooth tread for landfill and waste compactors. | Landfill compactors, RTLT |
| C-2 | Lug | Deep lug pattern, traction-focused compaction. | Waste compactor, soil compaction |
| Code | Description | Typical fitment |
|---|---|---|
| SLM | Smooth multi-purpose for material handlers and port equipment. | Container handlers, RTGs, reach stackers |
| SKS | Standard pattern for skid-steer and small wheel loader applications. | Skid-steer, mini-loader |
| SDT | Solid drive tyre, port and industrial. | Port handlers, ferry decks |
The TRA code is one input when matching a tyre to a machine. The other inputs that matter just as much: load index, speed symbol, TKPH rating (heat capacity), compound type (heat- or cut-resistant), and star rating. The right tyre passes all of these – not just the code.
OTR tyres use two main naming systems: the older inch-based system (e.g. 33.00R51) and the metric / aspect-ratio system (e.g. 45/65R45). They look different but describe the same kind of thing: cross-section width, construction type, and rim diameter.
| Component | Means |
|---|---|
| 33.00 | Section width: 33 inches at the widest point of the tyre at correct inflation. |
| R | Construction: R = radial. The alternative is bias (no letter, or "-" between numbers, e.g. 33.00-51). |
| 51 | Rim diameter: 51 inches. The wheel rim this tyre fits. |
| Component | Means |
|---|---|
| 45 | Section width in inches (or sometimes a coded width – Bridgestone uses 45 for ~45" width). |
| 65 | Aspect ratio (section height as percentage of section width). 65 means height = 65% of width. |
| R | Construction: R = radial. |
| 45 | Rim diameter in inches. |
On the sidewall, after the size, you'll typically see a load index number (e.g. 200) and a speed symbol (e.g. A2, A5, B). The load index converts to a maximum load via a lookup table. The speed symbol indicates the maximum speed at which the load index applies.
The star rating (★, ★★, ★★★) indicates a reserve load capacity above the published load index. Five-star ratings exist but are rare. Each star adds a load capacity increment. A three-star tyre allows higher loads at the same speed – or the same load at higher speeds – than a one-star equivalent.
Pattern codes are manufacturer-specific. Bridgestone uses VRDP, VSDL+, VRPS, etc. Michelin uses XDR, XHA2, XLD D2. There's no cross-manufacturer standard for pattern code – only for the TRA service code that the pattern fits within.
Tyre mixing on OTR machines sits in AS4457 territory – the Australian standard for OTR wheel and tyre maintenance and safety. Manufacturer guidance from Bridgestone, Michelin, Goodyear, Yokohama and Continental is consistent on the principles, though specific limits vary.
Mixing rules exist because mis-matched tyres cause real failures. Heat separation. Bead damage. Uneven contact patch leading to handling loss. On a haul truck this is a fatal-incident risk. When in doubt, don't mix – replace the set.
If you're forced into a mixed configuration because the right tyre is on a 14-week lead time and the machine has to run – document the decision, run the machine at a reduced operating envelope (lower speed, lower load), and replace to a consistent setup at the first opportunity. For sourcing the right tyre fast: Jewell Tyres – independent traders move tyres the OEM channel can't.
Forty common terms that come up in OTR tyre conversations. Definitions are practical, not academic – what the term means and when you'd actually hear it used.
Off-the-road tyres fail in patterns. Understanding the patterns helps with the diagnosis after the fact and the prevention before. Eight common modes – what they look like, what causes them, what to do.
Tread sections lifting away from the casing. Sometimes a visible bulge before the tread leaves. Often catastrophic on a haul truck – full tread strip departure.
Heat exceeded the bond strength between tread and casing. Usually because the tyre ran above its TKPH rating – too much load, too much speed, too much ambient temperature, or all three.
Tyre is scrap. Reassess the haul cycle: recalculate required TKPH, upgrade the tyre rating, slow the cycle, or split the load. Repeats indicate a systemic mismatch.
A cut through the tread that exposes the underlying steel belt or fabric ply. Often from a hit by a large rock or sharp object. May be repairable depending on size and location.
Single high-energy impact, typically from haul road rock or a poorly placed bench at the pit. May indicate haul road condition needs attention.
Small cuts (<25 mm, away from sidewall): section repair viable. Larger cuts, sidewall cuts, or cuts through to the bead: scrap. Investigate haul road condition.
Tread separation at the edge where the tread meets the sidewall. Often visible as a bulge or split running circumferentially around the tyre.
Shoulder area runs hotter than the centre of the tread under most loads. Persistent under-inflation accelerates this. Heavy side-loading (cornering) contributes.
Tyre is scrap. Audit inflation pressure management. If the machine corners hard, consider whether the tyre's load index includes adequate sidewall reserve.
Visible damage to the bead – the reinforced inner edge that seats on the rim. Can be cuts, distortion, or visible wire from the bead bundle.
Improper mounting (forcing the tyre over the rim), rim damage transferring to the bead, or extreme overload. Sometimes from running flat.
Tyre is scrap. Inspect the rim – a damaged rim will repeat the failure on the next tyre. Review mounting procedure with the fitter team.
The wheel rim itself is bent, cracked, or has a damaged flange. Often visible only when the tyre comes off. May cause repeat bead damage on successive tyres.
Impact (kerb strike, rock hit, ramp drop), heat from a flat run, or fatigue cracking. Sometimes from misuse during demount.
Don't fit a new tyre to a damaged rim. Inspect, refurbish or replace the rim. AS4457 specifies rim inspection cycles for high-cost OTR rims.
A bulge or weakness in the sidewall, often with internal fibre damage visible after demount. May progress to a sudden blowout.
Sustained under-inflation flexing the sidewall beyond its design envelope, generating heat. Sometimes from running on a kerb or against fixed objects.
Tyre is scrap. Audit the inflation management programme – daily or per-shift pressure checks are standard practice on tier-one mining contracts.
Internal layers (ply) breaking down, often invisible from outside until a bulge appears or air leaks through the casing. Sometimes evident only post-failure when the tyre is dissected.
Sustained overload, age, water ingress through unrepaired cuts, or manufacturing defect.
Tyre is scrap. If a pattern emerges across multiple tyres of the same age and brand, raise with the supplier – could be a batch quality issue.
Chunks of tread rubber breaking away from the surface. Distinct from cuts – this is the rubber itself fragmenting, not being sliced.
Compound mis-match – cut-resistant compound used in heavy heat-stress duty, or vice versa. Sometimes from rapid wear at the end of a tyre's life.
If early in tyre life: review compound selection. If late: normal end-of-life behaviour – plan replacement.
One tyre failing is an incident. Three tyres failing the same way in the same fleet position is a systemic problem. Track failures by mode, position, brand, batch and operator. Patterns will appear before catastrophic events do.
AS4457:2019 – full title Earth-moving machinery – Off-the-road wheels and tyres – Maintenance and safety – is the Australian Standard that governs OTR tyre handling on Australian mine and civil sites. Tier-one mining contracts require compliance. Insurance, work-health-and-safety regulators, and procurement teams all reference it.
This is a summary in plain language. The actual standard is the authoritative document – purchase from SAI Global or Standards Australia if you need the formal text.
Jewell Tyres trades within AS4457 compliance: tyres sold include documented condition assessment, age, and provenance where known. Tyres that don't meet AS4457 standards aren't sold – they're scrapped through compliant disposal channels. More on the Jewell Tyres safety position →