What Is a Tire Made Of? How Are Rubber Tires Made?

Have you ever stopped to think about what your car's tires are made of? They're just black, rubber circles that help us get from point A to point B, right? Wrong! Tires are actually meticulously crafted using a variety of materials and processes. From natural rubber to synthetic compounds, each tire is engineered for optimal performance and durability.

So buckle up and join us as we geek out about one of our favorite subjects: tires.

Where Does Tire Rubber Come From?

Tire rubber, as the name suggests, comes from a plant called Hevea brasiliensis (H. brasiliensis). This tree is native to South America but is now grown in other regions including Southeast Asia and Africa. The rubber used for tire production comes from the sap of this tree.

Because of these organic ingredients, tires have about a 6 year shelf life. Before you buy new tires, check their manufacturing date. 

The process of obtaining the rubber sap, also known as latex, involves making diagonal cuts into the bark of the tree and collecting it in cups attached to the trunk. The liquid latex is then processed by heating it with acid to coagulate the proteins in it.

Photo: Jumpstory

This video from the Science Channel shows how rubber is processed into sheets. 

Once coagulated, the solid mass undergoes various processes such as washing, rolling, pressing or drying before being sent off for further processing into different forms including sheets or pellets that can be used in tire manufacturing.

It's worth noting that while natural rubber remains an essential component of tire-making today, synthetic rubbers such as styrene-butadiene (SBR) have increasingly been developed and are widely used instead due to their superior durability and resistance capabilities.

How Are Rubber Tires Made?

First, raw materials such as natural rubber, synthetic rubber, carbon black, and various chemicals are mixed together in a large machine called a Banbury mixer. This mixture is then heated to a high temperature, which causes it to become a sticky compound that can be molded into different shapes.

Next, the compound is shaped into long strips or sheets and fed through rollers that compress it to remove any air pockets. These sheets are then cut into pieces of the desired size using special machines.

The tire-building process starts with building up layers of rubber around an inner liner to form what's known as a "green tire." The green tire is then placed inside a mold where heat and pressure are applied for vulcanization - the process that binds the components together. After vulcanization, excess material from the edges of the tire is trimmed using specialized equipment. Each tire undergoes rigorous quality control tests before being sent out for use on vehicles.

Making rubber tires requires precision, engineering and attention to detail at every step of production to ensure safety on our roads. 

This video from Michelin's YouTube channel shows how more than 200 ingredients are used to make truck tires!

Read more: Anatomy of a tire

What Is the Structure of a Tire?

Understanding the structure of a tire can help you appreciate how it works and lasts for so long. Tires consist of various layers, each playing an important role in ensuring their durability and safety.

The innermost layer is called the carcass, composed of cords running perpendicular to the direction of travel. The sidewall is reinforced with rubber-coated steel wires that give tires their shape while protecting them from damage. The tread layer provides traction and contact with the road.

Between these layers are more components like belts made up of steel or synthetic materials to keep the tire rigid at high speeds. There's a layer called a cap ply which enhances stability while also preventing air pressure loss over time.

Tires are complex structures that require careful manufacturing processes to create compounds durable enough for everyday use on different road surfaces. Knowing what your tires are made up of can help you maintain them better by checking air pressure regularly and rotating them often for even wear distribution.

Main photo 19528764 | Ninthsun9 | Dreamstime.com