Apollo tyres plant visit: Cooking car tyres

For a layman, a tyre is made of rubber, treated from its natural state and shaped to make it roll and wear evenly. For someone who knows and cares a bit, a tyre is built from layers of different materials, bears a distinct tread pattern and depending on its compound, can alter the performance and efficiency of a vehicle to a vast extent. Either way, how many have seen tyres being made? Not many I suppose, and so we couldn’t resist the chance to witness the making of a tyre.

Cut to the Apollo tyre factory in Chennai where a tyre is manufactured every eleven minutes on an ideal day. First thoughts after looking at the layout of the plant is that one could relate it to a kitchen, one Masterchef himself would be proud of. The plant is spread across acres of land and is capable of manufacturing 500 tonnes worth of tyres (16,000 per day in tyre numbers) and is undergoing an expansion to make 750 tonnes. Over a month, Apollo manufactures 2.5 lakh tyres that are built on two assembly lines. Here’s how it is done…

Raw rubber is about 70 percent of a tyre. It comes in trucks and is dropped off at a common point where raw rubber is mixed and processed to form sheets of rubber. They are melted and cut and mixed a couple of times to make the entire sheet of rubber of equal strength at any point. This sheet is about 40 metres long. In the melting process, a mix of materials determined by men in lab coats is added to the rubber. This defines the compound, soft/medium/hard in most basic terms, of the batch of tyres that are being cooked.   

There you have it, the most important step of the cook, getting the premix done. The sheets are then sent to two assembly lines, one for commercial vehicle tyres and one for passenger car tyres. Let’s focus on the passenger car tyres now on. 

A tyre has various ingredients – first comes the tread or the grooves you see on the surface of the tyre which is your contact patch on the road. It needs to be deep enough to a minimum of 5mm to turn your tyres from becoming racing slicks. Then comes the sidewall, which obviously is the side of the tyre. The tread is harder as it is subject to most wear. The sidewall has to be of a softer compound to flex and cushion bumps but with the elastic strength to not lose form. Then there is an inner liner which does the job of a tube in a tubeless tyre. The inner edge of the tyre is called the bead apex. It is the hardest part of the tyre as it comes in contact with the rim of a wheel and needs to maintain its shape at all times. Under the tread are two layers of steel wires set in position by a layer of rubber that holds them in place. 

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These two belts are mixed with rubber by a process called calendaring – the consolidation of steel and rubber. A massive machine pulls in long strands of the steel wire and blends in the rubber to form a thin sheet at 60 metres per minute. It’s a fairly violent process to say the least, and to keep the machine in check, we found these massive 8 caliper brake discs just in case something went wrong, or the machine has to be stopped after the loop of wires ran out. 

All these parts – the two belts, the inner liner, the bead and the tread are all brought together in the next step. This is called the green tyre or raw tyre, one that is sent to the moulding machines. The moulding is where all the magic happens. It is where the tyre is cooked for a minimum of eight minutes. What you get at the end of the moulding process is a finished tyre ready to be branded. 

By the end of it, it is hard to tell the different parts of a tyre to the naked eye. They are however made separately and accurately brought together. You will get a neat cross section of your tyre if you slice it through. We recommend doing some donuts though, at least you will know what the chicken mesh looks like, because after cooking comes burning, and we like burning rubber the right way don’t we!