Tyre Clinic
Bridgestone Tyre Clinic

2. Basic Tyre Information

  • a. What are the four major functions of a tyre?
    • - Although most vehicle-users do not place much attention to their tyres, the humble tyre has a very important and crucial job in allowing people to travel around.
      • 1. Loading Performance / To carry the weight of the vehicle and its passengers.
      • 2. Transmission Of Forces / To transmit driving and braking forces of the vehicle to the road through the tyre’s footprint.
      • 3. Manoeuvrability & Stability / To change and maintain the direction of the vehicle.
      • 4. Driving Comfort / To absorb shock from the road by elasticity of the air within the tyre.

b. Does a tyre have an anatomy?

  • - Yes, even a simple looking tyre has a complex anatomy structure. With a high technology product, there are many components that make a tyre durable and able to perform with ease.

Casing is the main body of a tyre. It maintains inflation pressure within the tyre and endures the load and shocks from the road.

Stell belts are reinforcing cord materials placed between the tread and the casing. Their function is to bind the casing firmly, similar to the hooping of a barrel, so as to enhance the lateral stiffness of the tread.

Edge covers are implemented to reduce the sheer stress experienced when the tyres are travelling at high speeds. The purpose is to improve tread durability.

Cap plies are much like the steel belts, except that the sheets are composed of woven fibers. These inelastic plies help to hold the tyre's shape and keep it stable at high speeds.

Sidewall are the portions of a tyre contour which do not have direct contact with the ground. They are here for the protection of the casing. Sidewalls are the parts which are subjected to the most severe flexing.

Beads consist of bundles of high carbon steel wires. They serve to support the casing cords, to anchor the plies and to hold the entire assembly on the rim.

Tread is the outer

c. Are there functions to the design of my tyre's tread pattern?

  • - Yes and they are all important factors to how tyres perform and keep us safe. Here are the descriptions for each of the different functions.

Sipes are small slit like grooves in the tread blocks that allows the blocks to flex. This added flexibility increases traction by creating an additional biting edge and are helpful on loose dirt.

Grooves create voids for better water channeling / evacuation on wet roads.

Blocks are the segments that make up the majority of the tread, and their primary function is to provide traction.

Ribs are a straight lined row of rubber for better straight line driving.

Dimples are indentation in the tread, normally towards the outer edge and aids cooling.

d. How do I read the sidewall markings on the tyre?

  • - No, they are not random alphabets on a tyre. They all are useful in helping to identify the tyre in question. Below are the explanations for the different markings.

DOT Code

1) ‘DOT’: Indicates that the tyre meets or exceeds the stands set by the United States of America Department Of Transport safety standards.

2) ‘7G’: Manufacturer & Plant codes.

3) ‘H8’: Tyre size codes.

4) ‘P6P’: Optional codes.

5) ‘18’: Week of production, ‘13’: Year of production.

Mould Number

A mould number identifies the mould in which the tyre was cured. This helps in tracking the mould of the original manufacturer.

Construction Details

This marking provides detail of the number of layers in each area of the tyre and the material used.

UTQGS Marking

An UTQGS (Uniform Tyre Quality Grading System) marking is required for passenger car tyres sold in USA. It is a method to indicate the quality (in terms of performance) of a tyre. It consists of 3 components, Treadware / Traction / Temperature.

i. Load Index Chart

i. Speed Symbol Chart

e. Where to can I find tyre information?

  • - To know recommended tyres sizes and inflation pressure, you can refer to either the vehicle tyre placard found on the door pillar of the front door, on the refuelling door or the owner’s manual.
  •   The tyre placard contains information about the OE tyre size specified by the car manufacturer. It is highly recommended to follow the correct size and inflation pressure.

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