We talk about tires all the time, but have you ever thought how are they made? Making a tire is a complex process and there are a lot of factors kept in mind to make certain types of tires. Construction of each type of tire differs from the other, for example, construction of an ordinary car tire of your Corolla or Civic is going to be very different from the construction of tire of a 4×4 or heavy duty vehicle like a loader.
For now, let’s see how your car tire is made. Long gone are the days when wheels were made of wood, or metal. In early twentieth century, with the invention of air filled tires, things changed drastically.
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Your modern tires are made up of ten to fifteen different components, like different kinds of rubber (natural and synthetic), chemical additives, and a pigment called ‘carbon black’. Under extreme pressure and heat, these components are mixed in giant blenders. The proportion of components depend on what kind of tire is required. The product is a soft dough like rubber which is made into sheets by the machines.
Next, polyester fabric is loaded into a machine called ‘calendar‘. What calendar does is apply warm and soft rubber to the both sides of the fabric. The product is a rubberized fabric and will be used to strengthen the tire structure. Rubber alone isn’t tough enough to make a tire. This sheet of rubber and fabric gives it the sturdiness it needs to perform in all sorts of conditions.
In the next step, that rubberized fabric is laced with several cotton cords and those rubber fabric sheets are piled on each other. The cotton cords help to vent the hot air, when tires go through actual construction.
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Three different rubber formulations are required to make tire treads. A machine called extruder is used to make streams of those three rubbers, which then enters a machine that makes them into one. A blade then cuts the long sheet of rubber into the size of the tire.
After that, steel wire are used to make the beads of the tire that makes it possible for it to stay on the wheel rim. A machines is used to give them the desired shape and size. Rubber wheel hoops laced with steel wires are made to be used later in the final construction of the tire.
Tire is ready to form its final shape. On a rotating wheel, both sides of bead hopes are mounted, in the middle, the actual layering of the rubber starts in the shape of the actual tire. First, the skeleton of the tire is made, it is inner part of tire, and beads are connected to this part.
Outer layer is assembled separately, with the strips of rubber, embedded with steel cords. On my last visit to General Tyres plant in Karachi, I was told 112 strings of steel wires are used for their tires. That sheet of rubber is wrapped around another tire making machine drum, where narrow strips of rubber ply are applied to it.
Now the final part where tread rubber is applied to the plies. After that, a machines transfers the out tread and ply part of the tire to where inner part or skeleton of the tire is held. Compressed air is pumped into the inner part of the tire, and all the rubber layers throughout the construction of the tire fuse together. The machine the then rolls over the edge of the tread rubber to the sidewalls. It is called a ‘green tire‘. Green tire is a tire that is uncured and doesn’t have a tread pattern in it.
Green tire is then placed in a mold to bake and shape it. It’s like an oven, where under heat and pressure, the tread patterns are engraved with automatic mold mechanism. Heat and pressure the tire went through makes it vulcanized. Excess rubber is trimmed from the finished product. After the final inspection, the tire is now ready to be shipped to the vendor. That tire is ready to be mounted on a wheel and hit the road.
It’s a very shortened way of explaining the otherwise very long and complex process of tire making, but we hope it helped you understand how do your Euro Stars or any other regular car tires are made.