Protected: Power is Nothing Without Control – Technical Piece

The step-by-step process


The journey has begun.

Deep in the heart of Pirelli’s state-of-the-art factory in Izmit, Turkey, work is underway. The Rally D’Italia Sardegna, one of the sport’s hottest, hardest and – in tyre terms – most inhospitable events lies in wait.

What happens here and now will connect a seven-time world champion and the fastest rally car ever created to planet earth. Power, as Pirelli has always said, is nothing without control.

A month ago this Scorpion KX H being fitted to Sébastien Ogier’s Toyota Yaris WRC was a collection of 30 component parts. This is the story of a chemical romance that created black magic. 

The tyre’s carcass is stage one of this process. These are, if you like, the foundations of the tyre. This is where tree-tapped latex arrives into Izmit as baled rubber sheets. Already, there’s been an extensive quality control procedure. Out in the field, between the trees in Malaysia, the white sap is sampled. Being a natural product, the calibre of the latex oozing from the knife-opened bark is dependant on the conditions its grown in; unexpected monsoon conditions, an overly dry winter or baking summer impact the harvest like they would any other crop.

To counter that, Pirelli draws its latex from multiple sources to maintain consistent quality and performance characteristics. 

The premium-produced natural rubber is cut from the bale and combined with synthetic polymers. This is where the science starts. The balance of synthetic polymers is crucial in deciding the product outcome in terms of wear resistance and the performance and durability curves. 

Carbon black is added to the mix. This gives the tyre its colour, but it also adds the beef. A hard compound Scorpion like the one we’re working on here has more carbon black than a soft tyre. Wear resistance is vital for an abrasive event like the Acropolis.

Were we making a soft compound tyre for cooler, damper conditions, there would be less carbon black and more silica in the mix – this would maintain a stickier consistency to the compound, affording the tyre less wear resistance but enhanced ability to grab, grip and stick to the road.

Again, Pirelli is picky about its supplier. The finer the carbon black granule, the better its molecular structure will mix with the polymers, the better resistance it will provide. Pirelli picks only the finest of fine granules. 

At this point the carcass – which still has a sticky, plastic feel to it – is partially inflated to give it a round shape.

Welcome to stage two. The Scorpion is handover over to another operator, who will work on a drum machine to apply the steel or Kevlar composite belts around the outside of the carcass. This is where Pirelli’s patented zero-degree banding technique pays dividends in ensuring geometrical stability, essentially ensuring there’s no growth in the tyre while it’s on the car and doing its thing. 

The sidewall is constructed with eight-mil, crescent-shaped rubber inserts. This generates exceptional protection from protrusion and cutting. It also provides the tyre with the ability to be self-supporting in the event of a loss of pressure. 

If you’ve ever wondered where the technology for the run-flat tyres on your road car came from, it’s right here. This is rallying working perfect harmony with the road.

This is a crucial time in the production process, it’s here that Pirelli’s hands-on approach is vital. While digitally-guided machinery puts the components together, every tyre is guided through the process by a human operator. There’s a constant quality control going on, safe in the knowledge that producing a tyre slightly too hard will impact on performance. Conversely, skimp on the strength and the tyre could be compromised by one of the millions of razor-sharp rocks that lie in wait on the roads around Lamia.

The line is fine, but it’s walked every day by the Pirelli’s professors of perfection.

And it’s been walked for weeks, months and years before now. Turkey is the €140 million production base, the firm’s so-called ‘factory of champions’ where its high-end Trofeo road car tyres are made alongside those to be fitted to the world’s fastest race and rally cars. But it’s back at base in Milan where much of the research has been done for this Scorpion tyre.

Pirelli’s vast hometown facility has cutting-edge technology for indoor running and flat-bed testing. The carcass we’ve just being put together will be put to the sword in Milan. The tread pattern is shaved off the Scorpion (to prevent the blocks flying off in the process) before it’s run mercilessly on the flat-bed machine. Beyond the performance of the carcass itself, this process examines the slip angle as well as longitudinal, latitudinal and torsional rigidity.

This level of destructive running is vital in high-speed fatigue testing.

It’s also vital in ensuring consistent production levels, another inbuilt quality control. Vital to Turkey’s success is the plant’s ability to manufacture sophisticated tyres with complex specifications to the most exacting standards. And all in very small batches. 

Back on the floor, the sidewall is coming together – so this is the point to formalise the tyre’s existence with a bar code and data broadcast antenna sealed into the sidewall. The final part of this process is to public-facing aspect of the Scorpion: the tread pattern.

The tread is delivered via a single, spirally applied strip of rubber; think rolling a ball of wool. The reason the tread’s not laid in strips like the belts before it is to avoid any later joins across the footprint of the tyre. Application via a spaghetti-like process ensures there are no weak points across the tread.

Once the tread is applied, it’s time to vulcanize. Fitted into a laser-guided millimetre-perfect mould, the tyre is baked under pressure. Out of the oven and allowed to cool, the final stage of the process is the dressing of the tyre with the all-important Pirelli decals. 

Famous yellow lettering complete, our Scropion is sent to the distribution area of Izmit, where it will be loaded onto a truck and sent in the direction of the service park.

Unless it falls foul of statistical analysis. A percentage of Pirellis go through the whole painstaking process, only to be dissected and put under the microscope – just to make sure the process is perfect. Again, quality control is everything when you’re busy winning world championships.

But our Scorpion has made it. It’s journey is complete. Almost. 

The stage is set. The world is waiting.