Tread (Part that comes in direct contact with the road)
With the exception of certain special tires, various characteristics exist for tire treads (the part of the tire that meets the road). These characteristics are becoming more complicated as applications grow more diverse with the development of roads and vehicles.
Shoulder (Shoulder of the tire)
Located between the tread and sidewall, the shoulder rubber is the thickest so that the design must allow for the easy diffusion of heat generated within the tire while driving.
Sidewall (Side of the tire)
The part between the shoulder and bead, the flexible sidewall protects the carcass and enhances the ride. A tire’s type, size, structure, pattern, manufacturing company, product name and various characters are indicated here.
Bead (Part that comes in contact with the rim)
The bead attaches the tire to the rim and wraps the end of the cord fabric. Comprised of the bead wire, core, flipper and other parts, the bead is generally designed to be slightly tight around the rim so that in the case of a sudden drop in inflation pressure, the tire will not fall off the rim.
Carcass (Tire framework)
As the most important framework of a tire, the entire inner layer of cord fabric is called the carcass. The carcass acts to support air pressure, vertical load and absorb shocks.
Breaker or Belt (Layers between the tread and carcass)
The breaker is a cord layer placed between the carcass and the tread in order to protect the carcass of a bias tire. The breaker reduces shocks, prevents rips or injury of the tread from reaching the carcass directly while also stopping the separation between the rubber layer and the carcass.
The belt is a strong reinforcement found between the tread and the carcass in a radial or belted bias tire. It functions much like the breaker but also increases tread rigidity by tightly winding about the carcass.
The inner liner is made of a layer of rubber that resists air diffusion and replaces the inner tube within a tire. Generally made of a synthetic rubber called butyl, or a rubber of the polyisoprene variety, the inner liner maintains the air inside the tire.