TyreFinder Tyre Reference Guide

Everything you need to understand tyre specifications, ratings and selection for passenger, commercial and OTR applications.

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Speed Index

The speed index indicates the maximum speed a tyre can safely sustain under its rated load. It applies to passenger vehicles, SUVs, light commercial vehicles, trucks, buses and industrial/ OTR tyres.

Speed Index Table

Speed Index Maximum Speed (km/h)
A1 5
A2 10
A3 15
A4 20
A5 25
A6 30
A7 35
A8 40
B 50
C 60
D 65
E 70
F 80
G 90
H 210
J 100
K 110
L 120
M 130
N 140
P 150
Q 160
R 170
S 180
T 190
U 200
V 240
W 270
Y 300

Load Index

The load index indicates the maximum load a tyre can carry at a specified pressure. It applies to passenger vehicles, SUVs, light commercial vehicles, trucks, buses and industrial/ OTR tyres.

Load Index Table

Load Index Maximum Load (kg)
70 335
71 345
72 355
73 365
74 375
75 387
76 400
77 412
78 425
79 437
80 450
81 462
82 475
83 487
84 500
85 515
86 530
87 545
88 560
89 580
90 600
91 615
92 630
93 650
94 670
95 690
96 710
97 730
98 750
99 775
100 800
101 825
102 850
103 875
104 900
105 925

TRA Codes

The TRA system, developed by the Tire and Rim Association (TRA), classifies off-the-road tyres based on application and tread depth.

Application Codes & Tread Depth

Code Application / Meaning Details
E – Earthmover E2, E3, E4, E5 E2 = Traction
E3 = Standard / Rock
E4 = Deep Tread
E5 = Extra Deep
L – Loader / Dozer L2, L3, L4, L5 L2 = Traction
L3 = Standard
L4 = Deep Tread
L5 = Extra Deep
G – Grader G2, G3 G2 = Traction
G3 = Rock
C – Compactor C1, C2 C1 = Smooth
C2 = Light Tread
LS – Log Skidder Forestry Applications Used for logging and skidder operations

Tread Depth Meaning

Depth Code Meaning
2 Traction – Soft Ground
3 Standard – General Use
4 Deep – Longer Wear
5 Extra Deep – Severe Conditions

Tyre Compound

  • Balanced Compound: General use, even performance across conditions.
  • Heat-Resistant Compound: Long haul distances, high speeds, reduces overheating.
  • Cut-Resistant Compound: Harsh, rocky terrain, resists damage, generates more heat.

TKPH

TKPH (Ton-Kilometres Per Hour) measures a tyre's working capacity. It represents the relationship between load, distance, and speed. High TKPH increases heat, which is the primary cause of tyre failure.

Tyre Size

  • Passenger & Light Vehicle Example – 245/70R16: 245 = width in mm, 70 = aspect ratio, R = radial, 16 = rim diameter in inches.
  • OTR Example – 46/90R57: 46 = width in inches, 90 = aspect ratio, R = radial, 57 = rim diameter in inches.

Application Guide

  • Mining: E3 / E4 tyres – focus on heat and load.
  • Quarry: L4 / L5 tyres – focus on cut resistance.
  • Construction: Mixed applications – balanced compounds.
  • Agriculture: Low ground pressure – traction-focused tyres.

Cost Per Hour

  • Cheap tyre – shorter life.
  • Premium tyre – longer life.

Lower cost per hour = better value for commercial operations.