Find out what the car tyre markings mean Ever notice those numbers on the sidewall of your tyres? Have you wondered what they mean? In this post we’ll tell you what those car tyre markings mean and their importance. All tyres will have the name of the manufacturer in bold such as Apollo, JK Tyre, Yokohama, MRF followed by the tyre name which can be actual words such as “A Drive” in case of Yokohama or “Wanderer” or just alphabets such as “ZVT” on a MRF. What you will also see is a string of alphabets and numbers such as the one in the picture below. This is of importance to us. Let’s decode this.
Here’s a pic of a Yokohama A Drive tyre
A – Section Width 175 – This is the section width of the tyre in millimeters. It’s the measurement for the tyre’s width from the inner sidewall to the outer sidewall. This is measured without placing any load on the tyre and after it’s been mounted on the appropriate rim and has been inflated as per specifications. The specs for maximum tyre pressure will also be mentioned on the tyre.
B – Aspect Ratio 65 – Measured in percentage, this is section height of the tyre with respect to the section width. In this example, it means that the section height is 65% of section width of 175 which is approximately 114 mm. A higher aspect ratio means that the tyre is best suited for bad roads.
C – Construction R – Stands for Construction Type which in this case is Radial. Some tyres will have a B which stands for Bias Belted or Cross Ply. Here’s the difference
Source: www.bridgestone.co.in In a radial tyre plycords run from bead to bead in a radial manner and are protected with dual steel belts, which makes tread very stiff. But in bias tyre plycords run diagonally and are protected with nylon breakers.
D – Rim Diameter 14 – is the diameter of the inner rim in inches.
E – Load Index 82 – This indicates the amount of weight this tyre can carry safely at maximum speed. The index normally ranges from 70 to 110. The table below shows the load index and the maximum weight per tyre. The tyre in the picture can carry 475 kgs per tyre. SUV and MUV will have a higher load index than sedans or hatchbacks. You will also see the actual Max Load mentioned in one of the markings on the sidewall. Load Index and Maximum Load per Individual Tyre Load Index
Load (kg)
Load Index
Load (kg)
Load Index
Load (kg)
Load Index
Load (kg)
70
335
81
462
92
630
103
875
71
345
82
475
93
650
104
900
72
355
83
487
94
670
105
925
73
365
84
500
95
690
106
950
74
375
85
515
96
710
107
975
75
387
86
530
97
730
108
1000
76
400
87
545
98
750
109
1030
77
412
88
560
99
775
110
1060
78
425
89
580
100
800
79
437
90
600
101
825
80
450
91
615
102
850
F – Speed Rating T – This code indicates the speed rating for the tyre at maximum load. This will vary on tyres depending on the maximum permitted speed. Take a look at the table below. In the above example the max speed allowed is 190 km/hr. Do not get too carried away with the speed indicator. Always follow traffic rules and drive within specified limits. Replacing your tyre with a higher speed rating will not help in altering the speed or performance of your car. Speed Symbol Speed Km/Hr Q
160
R
170
S
180
T
190
U
200
H
210
V
240
W
270
Y
300
Other Markings / Indicators •
There will be additional markings such as “Tubeless” and “Radial” which are self-explanatory
•
Date of manufacture – 1113 in the below picture means that it was manufactured in the 11th week of 2013
Source: www.yokohamatire.ph
•
Maximum load and tyre pressure in Pounds per Square Inch (PSI). In the picture below the max load
allowed is 670 kg @ 340 kPa (Kilo Pascal – a pressure measurement unit) or 50 psi. Over inflated tyres are bad for fuel economy and could also cause tyre explosion. Please refer your owner’s manual for the optimum pressure.
So urce: blog.cochran.com
•
Tyre Tread Wear Indicator – You will see triangular symbols placed around the circumference of the tyre
indicating where the indicators are located. You will find the indicators placed between the tread groves and they are 1.6 mm in height. When your tyre tread depth reaches this level, you must replace the tyres immediately.
Source: www.falkentyre.in
Hope this post has helped in understanding the sidewall markings. The next time you are tyre shopping, you will know how to read them! We recommend you also read about the difference between wheel alignment and wheel balancing to help maintain your car in top condition.
Drive Safe. Happy Driving!
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