Loose or broken radial body cables on inside shoulder
Soft mushy rubber on inside shoulder
Damage beyond repair limits (see below in repair permissible limits)
To repair tyres with any one of the above conditions would result in a tyre that would not be safe for further use.
Diagram below shows repairable & non repairable area
Only T-T is the repairable area for passenger tyres. The sidewall area can be repaired in truck tyres.
Never conduct the repair under these conditions:
Repair tyres with a tread puncture larger than 1/4” (6mm).
NEVER repair tyres worn beyond the tyre’s tread wear indicators
NEVER perform a tyre repair without removing the tyre from the rim/wheel assembly for internal inspection. (Do not perform an outside-in tyre repair or on-the-wheel repair). It is essential that only a specially trained
person remove any tyre from the wheel when it has been damaged or is losing air. A thorough inspection for any internal damage can then be made.
Requirements for repair of tyres
Every nail hole repair must have a patch inside the tyre – A mushroom patch must be used
Patches should never overlap
Patches always should be aligned with their bead arrows pointing to the beads (truck tyres)
Any repair outside the crown area is section repair (only for truck tyres)
Do not make repairs where the injury damage extends into the shoulder/belt edge or where the injury extends at an angle into the shoulder area.
NEVER use only a plug (stem) or never use only a patch to repair a puncture. The injury must be completely filled with a suitable vulcanizing material or rubber stem and a patch must be applied to the inner liner to prevent air loss.
NEVER repair a tyre that has an existing, improper repair – the tyre must be scrapped.
NEVER substitute an inner tube for a proper repair or to remedy an improper repair in a tubeless tyre.
NEVER do excessive spreading of the tyre or tyre beads
NEVER buff the tyre inner liner too deep, exposing the tyre casing body (ply) cords. If this type of damage occurs during buffing, the tyre must be scrapped.
Automotive Tyre Manufacturers Association
PHD House, 4th Floor, Siri Institutional Area,
Opp. Asian Games Village, New Delhi – 110 016