How are Car Tires Made?
Car tires are much more complicated that they look. Capable of travelling huge distances and covering a wide range of terrains, they need to be tough yet also flexible.
Have a look inside the car tire production process to get an idea of how tires are made – and all of the safety checks and testing that takes place to ensure they’re roadworthy.
What materials are used to make car tires?
There are a few different raw materials that make up the typical tire, although these change depending on whether the tires are for cars, trucks or other vehicles. What’s more, many companies use proprietary chemical engineering processes and different ingredients to compound their tires, as a way to try and gain an edge over their competitors.
The materials most tires are made of are synthetic rubber; carbon black (for traction); natural rubber; various chemicals; and reinforcing components such as steel wire, steel cord, and polyester.
Traditionally, tires would have been made mostly from natural rubber but newer, synthetic compositions include chemical compounds called elastomer polymers, which are elastic, rubber-like substances.
Synthetic rubber is most commonly made up from styrene and butadiene, while natural rubber is made from the sap of rubber trees. Disruptions in supply chains, from fuel shortages to issues cause by the Covid-19 pandemic, have influenced the cost of raw materials and helped to drive innovation and experimentation in composites – despite the fact that natural rubber is cheaper than synthetic.
How car tires are manufactured
While there is some variation, the basic process for making a car tire is pretty standard.
Mixing the raw materials
The first stage is mixing rubber and various additives together in a large mixer called a Banbury machine. One the materials are thoroughly combined, the are cooled and rolled out to the desired thickness using a rolling mill. These sheets are then cut into strips.
Adding the beads
The beads of a tire are made up of a composite fixed loop. It is used to tie together the rubber and fabric layers and locks the tire over the wheel assembly with a strong grip.
Creating the tread
The tread is what helps a tire grip surfaces. It is created through processing the rubber in an extruder which uses a die plate to press heated rubber into the desired treads.
Creating the inner lining
Tires have an inner lining that is made using a butyl rubber. It is made in a calendar machine and its function is to hold pressurized air in a sealed tube which has a gauge control to allow the pressure to be maintained.
Assembling the tire
The rubber strips are then layered along with reinforcing materials, typically fabric, and adhesives on a tire-building machine. The beads are added and then the final layers of rubber. Once assembled, this creates a ‘green’ or ‘uncured’ tire. The rubber or fabric sheets are often named a ‘ply’, a car may have a three or four plies thickness while a truck will have more.
Curing the tire
The next stage is then placing the tire in a curing press, where it is heated at high temperatures. This curing process “vulcanizes” the rubber and produces the nail shape.
There will then be a series of final tests, including visual and x-ray checks bubbles, holes or tears in the tread.
How to test car tires
There are many different stages of testing needed to ensure car tires meet all of the necessary safety and durability requirements. Consumers also expect tires that look great and don’t make an excessive amount of noise. All of which means that a solid tire testing process is a top priority.
From rubber testing the main components and testing the adhesive bond between layers to the burst impact of the finished product, we can help you at every step of the way. Find out more about the types of machines and processes available in our guide to tire testing.
New tires – design and technology
When it comes to the design of brand-new tires, technology is taking a front seat. State-of-the-art ‘virtual’ technology can allow engineers to simulate three dimensions and the sense of touch, helping them get a sense of a potential tire’s suitability and make modification to the design without having to build a production model.
Computer aided design in tire manufacturing
This kind of advanced computer aided design technology is typically used by bigger manufacturers and automotive firms. Manufacturers of high-volume products may also make use of computer-aided manufacturing (CAM) systems in their production plants, to pinpoint exactly where to put each compound on the tire.
Smart tires and changes to testing
There is also a growing trend for ‘smart tires’, tires that have extras like the TPMS tire pressure sensor, which makes it possible for drivers to be alerted through their car when the air pressure is low. All of these new technological advances mean that new testing methods are needed to keep up with the evolution of the automotive industry.
Automotive tire testing from Industrial Physics
For tire and automotive testing you can trust, get in touch with our talented team. We have more than 50 years of test and inspect experience in the automotive market and are constantly developing our testing techniques to adapt to new materials and ever evolving safety standards. Get an idea of the machines and options available right now and browse our automotive testing solutions.