Bead - The part of the tyre, which is so shaped as to fit the rim and hold the tyre on to it. It has cores made of several strands of essentially inextensible steel wire with the end of the plies wrapped around the cores for anchorage.
Sidewall- The part of the tyre between the bead and the tread, which flexes in service.
Tread - This is the part of the tyre which comes in contact with the ground and through which the driving, braking and cornering forces are transmitted. It is made of a special rubber compound to give good wearing properties and in conjunction with the tread pattern to transmit these forces.
Ply - A layer of rubber coated fabric cords.
Carcass - The rubber-bonded cord structure of a tyre integral with the bead which provides the requisite strength to carry the load.
Breaker (Diagonal)- Intermediate rubberised fabric layers/plies between the carcass and the tread which helps bonding as well as protects the casing from road shocks.
Belt (Radial) - Layers of rubberised material underneath the tread with cords laid substantially in the direction of the tread centre-line that restricts the carcass in the circumferential direction and stiffens the tread area.