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How tyres are made

Blend or compound

A number of ingredients are used in a truck tyre’s rubber blend or compound. The proportions of those ingredients, which comprise several types of rubber, fillers and other ingredients, will depend on what the performance goals of the tyre will be. These ingredients are mixed in giant blenders known as Banbury mixers, becoming a black, gummy compound that is sent on for milling.

Mill

Once the rubber is cooled, it is sent to a special mill, where the rubber is cut into strips that will form the basic structure of the tyre itself. At the milling stage, other elements of the tyre are prepared, some of which are then coated in another type of rubber.

Build

The tyre itself is constructed, from the inside out. The textile elements, steel belts, beads, ply, tread, and other components are placed in a tyre-building machine that ensures every part is in the right place. This results in what looks like a relatively finished product, known as a green tyre.

Cure

The green tyre is then vulcanized in hot molds in a curing press. This compresses all of the parts of the tyre together and gives the tyre its final shape, including its tread pattern and manufacturer’s side wall markings

Inspection

Before a tyre can be considered ready for sale, it must be carefully inspected. This is done visually by trained inspectors, and then using machines designed to pick up even the slightest blemish or imperfection. A selection of tyres are taken from the line for x-raying, in order to search for potential internal weaknesses or failures. Our quality control engineers also randomly select tyres off the line and cut them open to study carefully every detail of their construction to ensure they meet Goodyear standards.

The parts of a tire

Apexes: Rubber fillers in the bead and lower sidewall area to provide progressive transition from the stiff bead area into the flexible sidewall.

Bead Bundle: The steel bead bundle properly seats and seals the tire on the rim and maintains it in position.

Belt: Multiple low angle steel cord layers providing strength to the tire, stabilizing the tread and preventing penetrations into the carcass.

Carcass or Casing: The body of the tire consisting of the beads, sidewalls and tread package.

Chafer: A layer of hard rubber that resists erosion of the bead zone by the rim flange.

Chipper: Layer of steel cables over the radial ply turn-up to reinforce and stabilize the bead-to-sidewall transition zone.

Compound: A mixture of rubber, oils and other materials that make up (most commonly) the tread.

Flap: A rubber band placed between tube and rim. It protects the tube from chafing and prevents damage to the tube by the rim.

Inflation pressure: The pressure to which a tire should be inflated when it is cold. It is normally expressed in kPa (kilo Pascal, 100 kPa = 1bar), psi (pounds per square inch) or bars (1 bar = atmospheric pressure which is approximately 14.5 psi depending on height related to sea level).

Innerliner: A layer of rubber in tubeless tires specially compounded to prevent air loss.

Load Index: The maximum load a tire is permitted to carry.

Radial: The body ply cords are placed straight across the tire from bead to bead. In addition, radial tires have belt plies which run essentially circumferentially around the tires, under the tread. They constrict the radial ply cords and stabilize the tread area.

Ply: The radial (900) ply transmits all load, braking and steering forces between the wheel and the road and withstands the burst loads of the tire under operating pressure.

Regrooving: Cutting worn grooves to a deeper design depth with a hot iron to increase the life of a tire.

Retreading: The replacement of a worn tread with a new one to extend the life of a truck carcass.

Rolling Resistance: Rolling resistance is exactly what it says. So the lower the rolling resistance the less effort is required to move the tire. This is a result of a multitude of influences including the tread compound and tire construction. It directly relates to fuel economy.

Rim: Alternative word for wheel which is commonly used in the tire trade. It is also the part of a wheel on which the tire is mounted.

Sidewall: The part of the tire providing protection for the ply and withstanding flexing and weathering.

Speed rating: The maximum speed a tire is permitted travel at.

Tread: Outer layer of the tire that contacts the road providing primarily traction and protects the carcass underneath.

Tread pattern: The design of the grooves to maximise grip whilst also maximising water clearance

Tube: A separate air chamber, compounded to prevent loss of air, inserted into tube-type tires.

Tubeless: A tire that does not require a tube.