Basic Tyre Information

Basic Tyre Information

Variety of tyre – Categories of the tyre types

Image:Passenger car tyres

Passenger car tyres

Passenger car tyres meet the needs of the various driving scenarios, including tyres for sports cars, luxury sedans, sport utility vehicle(SUV) and winter tyre for each vehicle.

Image:User information

Off-the-Road tires

Off-the-road tyres are utilized for large-scale machinery at construction and mining and other sites with no roads.
These tyres support machinery used at various civil engineering sites with excellent durability and head resistance.

Functions of Tyres – 4 Important Functions of Tyres

Image:Supporting the weight of your vehicle

Supporting the weight of your vehicle

Image:Absorbing road shocks

Absorbing road shocks

Image:Providing traction and braking

Providing traction and braking

Image:Changing and Maintaining direction of travel

Changing and Maintaining direction of travel

Tyre construction

Image:Tyre construction

  • Tread
  • Shoulder
  • Belt
  • Bead filler
  • Bead wire
  • Inner liner
  • Carcass
  • Bead
  • Side wall

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Tread
The tread is the part of a tyre that contacts the road surface.
the tread consist of a layer of rubber, compounded to suit the application purpose of the tyre, and the thickness serves to protect the belt and carcass. Depending on application a suitable tread pattern is moulded at the time of curing. The tread pattern serves the purpose of improving water drainage, providing traction, braking and cornering characteristics and aiding in NVH performance.
Shoulder
The shoulder on each side of the tread is designed to protect the belt and carcass of the tyre and to disspate heat generated during running to the atmosphere.
Belt
The belt is a reinforcement layer extending around the outer circumference of the carcass under the tread. It acts like an iron hoop in improving the stiffness of the tread area.
Bead filler
This is a reinforcement rubber that has a triangular cross-section and which is used to increase the stiffness of the bead.
Bead wire
A ring-shaped reinforcement material that is made by bundling together several steel wires.
Inner liner
The inner liner is a layer of special rubber that has high resistance to air migration.
Carcass
The carcass is the load-bearing framework that forms the body of the tyre. It is composed of rubber coated fabric laid in a radial direction. The carcass contains the inflation pressure aiding in supporting the load and absorbing impact.
Bead
The bead area supports the extremities of the carcass on each side of the tyre. This is the part of the tire that anchors the tyre to the wheel.
Side wall
The sidewall on each side of the tyre, between the shoulder and the bead is the section that deflects most during running. The rubber coating serves to protect the carcass.
Tyre dimensions

The picture shows where the tyre is measured for the tyre size code.

Image:Tyre dimensions

  • Total width
  • Section width(W)
  • Section height(H)
  • Inside diameter (Rim diameter)
  • Outside diameter

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Total width
The exterior measurement of a tyre’s width from inner to outer sidewall (including protective ribs and decorations) when properly mounted and inflated.
Section width(W)
The exterior measurement of a tyre’s width from sidewall to sidewall (excluding protective ribs or decorations) when properly mounted and inflated, but with no load placed upon the tyre.
Section height(H)
The measurement of the vertical distance between the tyre’s bead seat and outer tread surface when properly mounted and inflated, but with no load placed on the tire.
Inside diameter (Rim diameter)
The linear distance between bead seats measured at the widest point. This measurement may be in inches or millimeters.
Outside diameter
The linear distance between the tyre’s tread surfaces measured at the widest point. This measurement is taken with the tire mounted on the measuring rim and no load applied.


Tyre dimensions

Image:Tyre dimensions

  • Section width(mm)
  • Aspect ratio(%)
  • Radial construction
  • Rim diameter(inch)
  • Load index
  • Speed symbol
Load Index(LI)

The capacity of each tire in withstanding the load is referred to as the load capacity. The load index is a numerical code associated with the maximum load a tire can support.

LI Kg LI Kg
61 257 86 530
62 265 87 545
63 272 88 560
64 280 89 580
65 290 90 600
66 300 91 615
67 307 92 630
68 315 93 650
69 325 94 670
70 335 95 690
71 345 96 710
72 355 97 730
73 365 98 750
74 375 99 775
75 387 100 800
76 400 101 825
77 412 102 850
78 425 103 875
79 437 104 900
80 450 105 925
81 462 106 950
82 475 107 975
83 487 108 1000
84 500 109 1030
85 515 110 1060
LI Kg LI Kg
111 1090 136 2240
112 1120 137 2300
113 1150 138 2360
114 1180 139 2430
115 1215 140 2500
116 1250 141 2575
117 1285 142 2650
118 1320 143 2725
119 1360 144 2800
120 1400 145 2900
121 1450 146 3000
122 1500 147 3075
123 1550 148 3150
124 1600 149 3250
125 1650 150 3350
126 1700 151 3450
127 1750 152 3550
128 1800 153 3650
129 1850 154 3750
130 1900 155 3875
131 1950 156 4000
132 2000 157 4125
133 2060 158 4250
134 2120 159 4375
135 2180 160 4500
Speed Symbol

The SPEED SYMBOL indicates the maximum speed at which the tyre can carry a load corresponding to its Load Index under service conditions specified by the tyre manufacturer. (except for speeds above 210km/h, see the above section, “Load capacities and speed limits” respectively for Passenger Cars)

Scroll to the right
Speed Symbol F G J K L M N P Q R S T U H V W Y (Y) ZR
Speed (km/h) 80 90 100 110 120 130 140 150 160 170 180 190 200 210 240 270 300 Over300 Over240
Aspect Ratio

Aspect ratio is the section height expressed as a percentage
of the section width (e.x. 70, 65, 60, etc.).

Image:Aspect Ratio

Image:Aspect Ratio

  • Aspect Ratio(%)
  • H(Section height)
  • W(Section width)
  • ×100
  • Example
  • Overall diameter 205/65R15
  • 205×0.65×2
  • 15 inch×25.4
  • 648mm
  • Section height
  • Rim dia
  • 1inch=25.4mm
  • (A) Section width(W)
  • (B) Section height(H)