The typical radial tire consists of nine main parts.
1 Inner liner: An airtight layer of synthetic rubber (the modern equivalent of an inner tube).
2 Carcass Ply: The layer above the inner liner, consisting of thin textile fibre cords (or cables) bonded into the rubber. These cables largely determine the strength of the tire and help it resist pressure. Standard tires contain about 1,400 cords, each one of which can resist a force of 33lb.
3 Lower bead area: This is where the rubber tire grips the metal rim. The power from the engine and braking effort is transmitted from the rim of the tire to the contact area with the road’s surface.
4 Beads: They clamp firmly against the tire’s rim to ensure an airtight fit and keep the tire properly seated on the rim. Each wire can take a load of up to 3, 968 lbs without risk of breaking. There are eight of them on your car – two per tire. That’s a massive 31,746 lbs of resistance strength. An average car weighs about 3,307 lbs.
5 Sidewall: It protects the side of the tire from impact with curbs and the road. Important details about the tire are written on the sidewall, such as tire size and speed rating.
6 Casing ply: It largely determines the strength of the tire. It’s made up of very fine, resistant steel cords bonded into the rubber. This means the tire can resist the strains of turning and doesn’t expand due to the rotation of the tire. It’s also flexible enough to absorb deformations caused by bumps, potholes and other obstacles in the road.
7 Cap ply (or “zero degrees” belt): This important safety layer reduces friction heating and helps maintain the shape of the tire when driving fast. To prevent centrifugal stretching of the tire, reinforced nylon based cords are embedded in a layer of rubber and placed around the circumference of the tire.
8 Crown Plies (or belts): They provide the rigid base for the tread.
9 Tread: It provides traction and turning grip for the tire and is designed to resist wear, abrasion and heat.