Anatomy of a Tire

The Anatomy of a Tire

You do not need to be a professional in the tire industry to know that a tire is usually constructed from rubber and contains air to carry loads. However, not everyone knows what goes on underneath the tread pattern. There’s actually much to it in constructing a tire than meets the eye. In this article, we dissect a tire and name the relevance for each component.

Tread Pattern

This is the outside layer and is the part of the tire that comes  in contact with the (road) surface. It is designed with patterns specific to the tire’s use to provide traction. Tread patterns come in a large variety of forms, depending of the usage of the tire. Tread patterns come in different classes and within the OTR industry they are divided into the following categories: C for Compactor, E for Earthmover, G for Graders and L for loaders/dozers. Within these categories, the tire is marked with a number varying from 1 to 7 to indicate how deep or sturdy the tread pattern is. Very handy if you need to decide what specific tire to use! You can read all about it in this article.

Sidewall

The sidewall is, as the name suggest, the side of the tire. This extends from the edge of the tread pattern tot the bead. It offers lateral stability and has a big influence in the amount of driver/operator comfort the tire provides. In general, the sturdier a sidewall is, the more weight a tire can carry. Unfortunately that also means the tire is less forgiving for imperfections in the road surface, meaning a less comfortable ride for the operator. A tire always has a fine balance between sturdiness and comfort, depending on the application it was designed for.

Steel Belts

These are layers of steel wires coated with rubber. These steel belts are placed under the tread pattern to provide stability and to make the tread pattern puncture-resistant. The steel belts in the tire also help the tire to stay flat and in shape under load, overall improving the sturdiness of the tire.

Casing Plies

These are the layers of fabric making up the body of the tire, also adding to the strength and flexibility of the tire. Casing plies are usually made from materials such as nylon, polyester or rayon cords. Weight and strength are the two main factors in deciding what type of fabric is being used. It always comes down to the right balance for the specific task the tire is developed for. A heavier tire is stronger, but will also suffer from quicker heat build-up in the tire during operations, affecting the tire’s wear resistance. Tire weight also has a big influence on the vehicles fuel consumption, which will have a direct impact in the total cost per hour of the tire (TKPH). Ever wondered how to calculate the TKPH? Check out this article.

Inner liner

As the name suggest, this is the innermost layer of a tubeless tire, which retains the air inside. This effectively replaces the function of an inner tube.

Bead and Bead Core

The bead is where the tire is anchored to the wheel rim. Obviously, this needs to be a very strong seal as it also traps the air inside the tire and rim. The bead is a thick and strong piece of rubber with a steel cord within the bead. This steel cord is unsurprisingly called the bead core and is essential for keeping the tire on the rim. The flexibility of the rubber combined with the strong core means the tire grips around the rim perfectly.

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