We’ve said it before, your tires are the most essential piece of safety equipment on your vehicle. It’s vital that you maintain and have them replaced when necessary. And yet, despite how indispensable they are, we often don’t give much thought to the intricate process that forms those black rubber rollers that we spend so much time riding around on. Have you ever wondered what goes into making your tires? It’s really quite a marvel of modern technology that a century ago caused the sharpest engineering minds to lose a lot of sleep.
The Back Story
Let’s start with a little bit of history. Back in 1845, Robert William Thomson invented the first vulcanized rubber pneumatic tire. The trouble was that the final product was way too expensive for most consumers at the time. It was a brilliant idea, but it couldn’t be made cheaply enough, and so looking back, we say it was way ahead of its time. Fast forward a bit to the 1880s, and a man whose last name is probably familiar to you, especially if you play tennis, John Boyd Dunlop, was busy inventing the first affordable inflatable tire for bicycles. And, as is often the case, progress in one form of transportation leads to advances in another. A few short years later, André Michelin and his brother Edouard took the learnings from bicycles and were the first to use pneumatic tires on an automobile. However, while considerably advanced for the time, their product suffered from a whole host of durability issues that left the burgeoning automotive industry skeptical.
That’s where Philip Strauss comes in, in 1911, to solve the problem with a unique solution—a combination tire and air-filled inner tube. His state-of-the-art layering process created enough durability to allow pneumatic tires to be used on automobiles effectively and managed to keep the price low enough so that regular drivers could afford to keep driving. It’s really quite remarkable what we’ve accomplished in the tire industry in a little over one hundred years, from not having a durable rolling platform to drive on to developing a different sort of rubber tire for every possible driving niche.
Let’s begin with the basics. At their core, tires are a piece of sturdy yet flexible rubber that gets attached to the rim of the wheel to provide a gripping surface for traction and to serve as a cushioning layer for a moving vehicle as it rolls over any number of minor roadway variances. Tires offer your first and only contact with the road and allow for effective steering, braking, accelerating, and turning. The incredible engineering process of tires rarely gets the accolades it deserves for the amount of function they are responsible for on your car. We’re going to delve into the process and let you in on just how much technology you’re rolling around on daily.
The Right Stuff
The primary ingredients used in tire production today are natural and synthetic rubber. And while synthetic rubber compounds now make up to 60-percent of the tire, the remaining 40-percent still comes from a tree-product that has to be grown. The rubber tree or Hevea Brasiliensis produces a milky liquid in its bark, which solidifies into a shapable compound when mixed with acids. However, before it can be used, large presses have to squeeze out any excess water and form the rubber into sheets that are then dried in tall smokehouses before being packaged into gigantic bales for distribution to manufacturers.
When it comes to the synthetic rubbers used in vehicle tire manufacturing, the main two are butadiene and styrene-butadiene rubber. These rubber polymers are combined with natural rubber in varying degrees to create different types of traction, wear, and rolling resistance depending on the type of tire being manufactured.
Of course, another essential synthetic rubber is halogenated polyisobutylene rubber (XIIR), commonly known as halobutyl-rubber. This material causes the inner liner to be impermeable to air, which allows the tire to stay inflated despite all the bumps along the road. All of these synthetic rubbers are produced from polymers derived from crude oil.
The other ingredients that make their way into the finished product are metallic and textile reinforcement cables, carbon black, silica, sulphur, and various other chemicals. Let’s take a look at how it all comes together.
Reinventing the Wheel
Your car’s tires are made of four essential components that come together to ensure the engine’s power can be effectively translated into movement on the road. These components are the beads, the body, the sidewalls, and the tread. Many tires are custom designed to the desired specifications and performance needs of a particular vehicle model, but they still use these four components in their configuration. Depending on the tread design, the tires are optimized for specific conditions, such as winter driving, summer heat, off-roading, racetracks, or any number of specialty needs. And while in years past, manufacturers used clay modelling to design and test tread patterns.
Today, sophisticated computer systems can simulate road conditions, alter tire design, and adjust the rubber compound formula well before a prototype is ever produced. Of course, only after a prototype tire passes all inspections for safety, performance, and durability do the factories begin to mass-produce and distribute the new tire.
Producing Street-Legal Treads
The tire manufacturing process begins with a machine called a Banbury Mixer. This heavy-duty mixing bowl combines the raw materials for each compound into a regulated batch of black liquid. The mixing process is computer-controlled to assure consistency of the final product to international standards. The compounded rubber product is then distributed to various processing machines for finishing into sidewalls, treads, or other parts of the tire. Each of these components then needs to be fused together into the final tire design.
Once the body, beads, and tread of the tires are produced, tire construction can begin. The process starts by wrapping the rubber-covered fabric plies of the body around the machine drum. The beads are then added and locked into place, and specialized power tools shape the edges. Finally, the extruded rubber layers for the sidewalls and tread are glued into place, and the assembled product, called the green tire, is removed from the tire-building machine. The tire is then placed in a mould for the curing process before being inspected and tested prior to distribution.
Modern tire technology blends a unique mix of chemistry, physics, and engineering to give consumers a high degree of comfort, performance, efficiency, reliability, and safety.
Of course, like all mass-produced consumer products today, a tire manufacturing plant uses a mix of automated and human labour to turn a combination of source material into sophisticated automotive components on a large scale. Tire factories all over the world produce more than 250 million new tires every year.
Now that you know a little more about the tire-making process, it’s worth reviewing how you can best monitor and maintain your rollers. Check out our previous posts on Why You Should Store Your Summer Tires in Ottawa, How to Inspect Your Tires, and The Importance of Monitoring and Maintaining Proper Tire Wear. And as always, if you have questions or want to schedule a vehicle inspection, give us a call. At Sipan Tire and Rims, our team of automotive specialists loves to talk shop.