The internal ’skeleton’ in your tire consists of multiple layers which is called threads. The internal threads consists of a rubber coated textile fabric. The thread construction makes the tire flexible – without it being able to stretch. A big part of the tires strength is due to a sturdy thread layer called ‘casing thread’, which is placed above the center layers of the tire.
Steel belts strengthen the tire and adds stiffness. It is made from braided steel wire, which is covered by a rubber compound. Some tires also contain kevlar thread, which adds extra strength, lengthens the lifetime of the tire and adds greater sustainability to damage.
The faceted edge, where the external tire thread and the sidewall meet, is referred to as the ‘shoulder’. A tires handling in turns and maneuvering in sloped terrain is greatly determined by the ‘shoulders’ shape.
The deep grooves between the external tire thread are important, because they lead water, mud and snow away from the surface. Small cuts in the external thread blocks are known as lamella, and are designed to provide extra traction. The groove shapes are especially important for tires designed to run in difficult conditions, such as winter or heavy rain.
Beads create an airtight seal between the tire and the rim. It consists of powerfully braided steel covered in rubber.
The sidewall is the part of the tire, which is between the beads and the external tire thread. It consists of thick rubber, which increases the stability. Important information such as size, speed/load index and recommended tire pressure is printed onto the sidewall.
The wide external area covered in soft rubber, which is in contact with the road surface ensures tire grip and comfort. The two biggest factors that matter for a tires handling are; the shape of the external tire thread cuts, and the actual rubber compound.
The unbroken line that travels the middle and around the tire is known as a rib. Its purpose is to provide extra reinforcement.