What is the tyre casing?

The casing is the main structural body of the tyre. It supports the load carried by the tyre and helps the tyre maintain its shape while flexing as the wheel rotates.

A modern tyre contains several different components. Depending on the tyre design these can include body plies, belts, bead assemblies, an inner liner, sidewall rubber and the tread package. Together they form a structure capable of containing air pressure and transmitting braking, steering and acceleration forces.

Why can casing damage be serious?

Damage to the structural components can affect the tyre even when the outside initially looks relatively normal. Impact damage, prolonged driving at very low pressure, penetration into structural areas, ageing or separation can all make a tyre unsuitable for continued use.

A vibration, bulge, distortion or an out-of-shape tyre should be investigated rather than simply balanced or reinflated.

What does “casing” mean with retread tyres?

The word is also used for the tyre body that remains when a worn tyre is prepared for retreading. A suitable casing can be inspected and processed before a new tread is applied. Whether a casing is suitable depends on its condition and the applicable manufacturing/inspection requirements.

When should a tyre be inspected?

• After a significant pothole or kerb impact.
• If a bulge or distortion appears.
• After driving with very low or zero pressure.
• If unexplained vibration develops.
• When internal damage is suspected following a puncture.