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Understanding Tyre Markings

You will find the size of a tyre on its sidewall. With a quick explanation as to what the different numbers mean, you will see that it is very quick and very easy to find out a tyre's size.

Here's our simple guide to explain what some of them mean:

Load Index Conversion Table

The load index is a number indicating the maximum load capacity at which the tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted, and with recommended inflation pressures (Using the above diagram 79 represents a maximum load of 437kg per tyre).

Load index
Load in kg per tyre
Load index
Load in kg per tyre
Load index
Load in kg per tyre
Load index
Load in kg per tyre
Load index
Load in kg per tyre
62
265
75
387
88
560
101
825
114
1180
63
272
76
400
89
580
102
850
115
1215
64
280
77
412
90
600
103
875
116
1250
65
290
78
425
91
615
104
900
117
1285
66
300
79
437
92
630
105
925
118
1320
67
307
80
450
93
650
106
950
119
1360
68
315
81
462
94
670
107
975
120
1400
69
325
82
475
95
690
108
1000
121
1450
70
335
83
487
96
710
109
1030
122
1500
71
345
84
500
97
730
110
1060
123
1550
72
355
85
515
98
750
111
1090
124
1600
73
365
86
530
99
775
112
1120
125
1650
74
375
87
545
100
800
113
1150
126
1700


Speed Symbol Conversion Table

The speed symbol is a symbol indicating the maximum speed at which the tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted, and with recommended inflation pressures (Using the above diagram T represents a maximum speed of 190 km per hour).

Speed Symbol
J
K
L
M
N
P
Q
R
S
T
U
H
V
W
Y
VR
ZR
Speed in km/hr
100
110
120
130
140
150
160
170
180
190
200
210
240
270
300
>210
>240

Consult tyre manufacturer for further details of Z speed category


Treadwear

Uses numbers from 100 to about 700. Theoretically, a tyre rated 150 would have a 50 percent longer lifespan than a tyre rated 100 if used in the same conditions — driver, vehicle and roads. Soft summer tyres tend to have lower treadwear ratings than all-season tyres.


Traction

Uses AA, A, B and C, with AA being the best traction on a wet road. The traction measured is straight-line acceleration and braking. This is not a measure of cornering grip or performance on dry surfaces.


Temperature

Uses letter grades A, B and C, with A representing the best resistance to heat buildup and C the least. The friction of a tyre on pavement generates heat, and too much heat degrades high-speed performance and can accelerate aging and failure. C is the lowest permissible rating.


Production Date

All tyres are produced with a serial Tyre Identification Number (or serial TIN) that shows the date of manufacture of a tyre. The last four digits of the serial TIN indicate the week and year that the tyre was made. For example, if a tyre has a production date 0312 it means the tyre was made in 3rd week of 2012.

Most tyre manufacturer warrant their tyres against manufacturing and material defects for five years from the date of manufacture. Based on their understanding a number of vehicle manufacturers are now advising against the use of tyres that are more than six years old due to the effects of ageing.