Waves International Tyre – Truck, Bus, SCV, LCV & OTR tyre

Tyres

Topics covered in this presentation: ď Ž Wheels

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Terminology 

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Steel Wheels – A very popular design of wheel. Very strong and cheap to produce.

Alloy Wheels – Attractive and light weight, but can be difficult to clean.

Spoked Wheels – Used on older sports vehicles, but cannot be fitted with tubeless tyres.

Divided rims – the rims are made in two halves which are bolted together, the rims must never be separated while the tyre is inflated.

Split rims – the tyre is held in place by a large circlip, do not remove the tyre unless you have been properly trained

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Radial Ply Tyre – the main plies of the tyre run at 90 degrees from one bead to the other.

Cross Ply Tyre – the main plies of the tyre run at 45 degrees from one bead to the other.

Plies – Layers of strong fabric which are built up to give the tyre its strength and shape Bead – loops of steel which are the anchorage point for the plies.

Tread – this provides the grip with the road surface, the pattern assists in clearing any water away Side Wall – this connects the beads to the tread of the tyre.

Tyres (Introduction)      

Basis Functions The tyre acts as the primary suspension, cushioning the vehicle from the effects of a rough surface.

It also provides frictional contact with the road surface.

This allows the driving wheels to move the vehicle.

The front tyres allows the wheels to steer .

The tyres allow the brakes to slow or stop the vehicle

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Pneumatic Tyres     

The tyre is a flexible casing, which contains air.

Tyres are manufactured from reinforced synthetic rubber.

The tyre is made from an inner layer of fabric plies, which are wrapped around bead wires at the inner edges.

The bead wires hold the tyre in position on the wheel rim.

The fabric plies are coated with rubber, which is moulded to form the side walls and tread of the tyre. Behind the tread is a reinforcing band, usually made of steel,rayon,or glass fibre. Modern tyres are mostly tubeless, so they have a thin layer of rubber coating inside to act as a seal.

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Tyre Construction •

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Cross – ply tyres are not used on any mass produced modern cars. However, the construction details are useful to show how tyre technology has developed.

Several textile plies are laid across each other, running from bead to bead in alternate directions.

The number of plies depends on the size of the tyre and the load it has to carry.

The same number of plies is used on the crown and the sidewalls.

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Tyre Construction •

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Radial – Ply tyres consist of a carcass ply formed by textile arcs running from one bead to the other.

Each ply which is laid in an arc at an angle of 90 degrees to the direction the tyre rolls.

At the top of the tyre crown (under the tread), there is a belt made up of several plies reinforced with metal wire, laid on top of the carcass ply.

These crown plies, laid one on top of the other, overlap at an angle determined by the type of the tyre.

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www.wavesinternational.in Tyre Specifications

P 205/55 V R 16 TYPE P - PASSENGER T - TEMPORARY LT - LIGHT TRUCK C - COMMERCIAL

RIM DIAMETER (INCHES) 13, 14 ETC

ASPECT RATIO (HEIGHT/WIDTH %) 55, 60, 65 70 ETC

WIDTH (MILLIMETERS) 145-315

TYPE B - BIAS-BELTED D - DIAGONAL BIAS R - RADIAL

SPEED RATING B (31 MPH) V (150 MPH) Z (OVER 150 MPH) Next >

Special Service Tyre This is a space-saver spare tyre.

Used to replace flat tyre.

It is not used for rotation (swapping).

It uses a special wheel.

Speed and pressure restrictions apply.

It has no hub caps or wheel covers.

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Remember the tyre tread depth must be not less than 1.6mm over the central three-quarters of the tyre and must go all the way round the circumference in an continuous unbroken band with no bald patches anywhere on the tyre tread.

If radial and crossply tyres are fitted to the same vehicle, the radial-ply tyres must only be fitted to the rear.

Cross-ply and radial ply tyres must never be fitted to the same axle.

Tyre pressures must be set to the manufactures recommendations The tread and side wall must be free from large cuts, abrasions or bubbles

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www.wavesinternational.in Balance Wheel imbalance causes wheel tramp, or hop, makes the tyre vibrate up and down.

Centrifugal forces try to throw heavy areas outward when the wheel is spinning.

Weight must be evenly distributed around the axis of rotation.

Imbalance can be rectified in one of two ways by Static Balancing (stationary) or Dynamic Balancing (spinning).

www.wavesinternational.in Rotation A system of rotation is used to even out tyre wear and reduce the need for re-balancing.

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(a) 4-wheel bias (cross-ply) tyre rotation. (b) 5-wheel rotation (including spare).

Radial tyres must be kept on the same side of the car. (c) 4-wheel radial tyre rotation. (d) 5-wheel radials (including spare).

Care must be taken with spare as some modern tyres are directional.