Tire Structure 101

Have you ever wondered what goes into the construction of your tires? If your answer is yes, then today is your lucky day as we will take a look at the basic parts of a tire’s internal construction to give you a better understanding on the intricate puzzle-like structure of a tire’s insides.

A tire’s main components are its casing, belt package and tread area which work together to provide the handling and traction needed for its performance. These individual elements are molded together during the curing process which creates a single product out of them.

TIRE CASING

The tire casing is basically the initial body of the tire. In a way, it acts like its skeleton. The casing optimizes the tire shape with its components, which include the bead, the sidewalls, the body plies and the inner liner of the tire.

The tire’s bead structure features bead bundles that secure the tire to the wheel. The different elements of the bead structure work together to ensure the tire’s contact with the wheel throughout the tire’s lifetime when the correct inflation is maintained. It also prevents damage from occurring while the tires are mounted.

Different tires require different sidewall structures, but the main focus is the same. The tire’s sidewall needs adequate flexibility and weather damage resistance to ensure a safer performing ability. High performance tires may also feature steel belts to prevent the tire’s deformation under the high speed pressure affecting the models.

The body plies of the tire’s internal structure usually incorporate polyester, nylon or rayon cords within the casing rubber compound. These plies manage to reinforce the structure to optimize the ideal tire shape during the tire’s performance. Furthermore, these plies are responsible for ensuring a smoother performance and a fuel efficient drive with most models.

The tire’s inner lining is a special rubber compound that is used as an air seal on the tire’s inside. The inner lining is not strengthened with cords and it basically acts similar to an inner tube.

BELT PACKAGE

The next component of the tire’s internal structure is its belt package or system. The tire’s entire belt system is placed on top of the tire’s casing to reinforce the structural stability. The belts of the construction improve the tread stability, the tire’s controllability and the overall traction by optimizing the tire’s surface contact and driving stability.

A commonly used material to forge the belts is steel, which strengthens the structure, without significantly increasing the tire’s weight. These plies are typically placed two-by-two into the tires, stacked on top of one another to reinforce the structure and the model’s overall performance.

TREAD AREA

During the manufacturing process, the tread slab is put on top of the tire’s belt system to finish its construction. A tire’s tread can be divided into a tread base and a tread cap that form the tread area together.

The tread base compounds clock to the belt package during the curing process to strengthen the durability and to prevent tread separation. The tread cap compound is usually resistant to wear and offers a better surface gripping ability. The tread cap has to work together with the tread base to optimize the tire’s traction and mileage. Lastly, also during the curing process, these tread layers are molded into the tread pattern which will be featured on the tire.

Needless to say, tires manufactured for different vehicles – passenger vehicles, SUVs and light trucks – do not feature identical internal structures. Larger vehicles require stronger tires and, as a result, these tires offer better load durability. However, this also causes the tires to be heavier.