About this Article
Written by: Joseph Yeargan
Written on: July 5th, 2005
Tags: transportation, material science
Thumbnail by: Angie/Wikimedia Commons
About the Author
Joseph Yeargan was a student at the University of Southern California's Viterbi School of Engineering in the spring of 2005. He is an automotive enthusiast, and avid motor sports fan.
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Volume VII Issue I > The Four Most Important Parts Of Your Car
Most drivers do not know that the most important parts of any car are its tires. The tires have an enormous influence on the safety and performance of an automobile. While tires may appear to be simple devices, developing them is an extremely complex process. It is based on subtle design changes that can have significant effects on performance. It is essential that drivers understand automobile tires because they only work properly when they are driven under specific operating parameters. For instance, operating a tire at an improper inflation pressure can accelerate wear and cause dangerous damage to the tire. While engineers are developing entirely new tire design concepts for the future that solve some of these problems, it is important that drivers understand how their tires work today. With such knowledge, they can prolong the life of their tires and avoid dangerous driving situations.
Tires are the single most important safety and performance feature of any automobile. Since they are the medium through which the car and road cooperate, the performance of a car's tires greatly affects the engineering that goes into the overall vehicle design. Tires are in many ways very simple because they contain a minimal number of components and are relatively easy to manufacture. However, they undergo extensive, complex development with subtle design changes that have major performance implications.

How We Got Here

The theory behind the modern automobile tire is almost as old as the automobile itself. In 1895, Frenchman Andre Michelin placed air-filled, or pneumatic, tires on an automobile for the first time. The theory was to use air to support the weight of the car and cushion the ride for the passengers. The air-filled tires had many benefits over the solid tires of the day, which transmitted all the imperfections of the roads directly to the passenger compartment [1].
The next revolution was made by the B. F. Goodrich Company, which used the first synthetic rubber in its tires. The use of synthetic rubber enabled engineers to make more improvements to their tires because they could change the compound, or "recipe", used in the tire to create the desired result. This also reduced the dependency of the tire industry on natural resources. Engineers, however, have found that a mixture of natural and synthetic rubber is the ideal solution. As a result, most modern tires are composed of a mixture of the two types of rubber [1].
In terms of construction, modern tires are made almost exclusively with a radial construction. This has been the case for decades ever since Michelin applied the radial construction it was using for its racing tires to passenger tires.
Radial tires are built around two circular cables, which can be found on either side of the tire where the tire is mounted to the wheel. These steel cables are referred to as the bead bundles. Various materials are stretched between these two cables perpendicular to the tread. These materials, often polyester, form the tire casing, or tire body. They vastly improve the strength of the tire. Two steel belts are bonded to the outside of the tire casing around the circumference of the tire. These belts support the tire tread and give the overall structure of the tire more strength. Finally, the tread and sidewalls are built around these components [2].