March, 2012 (F1plus Team / Pirelli Press).- More overtaking, more pit stops, an even better show and races to remember. This was the mission for Pirelli to accomplish, according to the brief handed to the Italian tyre firm from Formula One teams and the sport’s promoter at the start of the year.
For any tyre manufacturer, it was an unprecedented challenge. But the target has already been met from the very first races. On Pirelli’s debut at the Australian Grand Prix, Sebastian Vettel set the fastest ever lap ever seen in the 15-year history of the Melbourne race, while in China a record number of 63 overtaking manoeuvres – more than one per lap – captivated the spectators. In between them there was the Malaysian Grand Prix, which saw no fewer than 52 pit stops and several moments of drama, putting the outcome of the race in the balance right up until the final laps.
The new Pirelli P Zero tyres guarantee high levels of performance and safety, together with a deliberate degree of degradation that adds an intriguing strategic element to the race, promoting overtaking both on the track and in the pits.
The 2012 Formula 1 Season PIRELLI season.
Maurizio Boiocchi, Pirelli’s Director of Research and Development, said: “Making tyres with these specific characteristics represented a challenge within a challenge. It would have been much easier to produce tyres that lasted for an entire race, as we already did in GP3 last year.
But what exactly is the right amount of durability? Theoretically, it shouldn’t be more than a maximum of 30 laps. If the tyres lasted 35 laps, for example, allowing long stints and just one stop, we would have failed to meet our objectives. The real trick was to know how to put together the ingredients for each tyre in exactly the correct proportions, because we obviously didn’t want the tyres to last for too short a period of time either. This was the main conundrum that our research engineers faced.
Then of course you have to remember that the tyres are the same for the whole season but they have to be equally effective on 20 different circuits, with hugely varying track and weather conditions, as well as on 12 different cars with 24 potentially different driving styles.”
In order to attain the objectives Pirelli worked in four main areas:
1. The shoulder of the tyre, which was developed with new technology in order to support high slip angles.
2. The carcass of the tyre, made out of composite materials and designed to improve the overall structural rigidity.
3. The tread pattern, the heart of the tyre, which determines the contact patch and so the amount of mechanical grip available.
4. The compounds, which determine the durability of the tyres.
So how is a Formula One tyre actually created? It all begins with research and development, with every step confirmed by continual checks both in the laboratory and on the track.
There are four essential phases of research and development:
1) The story begins in the Pirelli research laboratories, at the Bicocca area of Milan, which is synonymous with Pirelli. More than 400 people work there every day, the nucleus of a team that consists of more than a thousand people made up of chemists, physicists and engineers, split among the six Pirelli research centres all over the world. In Milan, 150 research engineers work exclusively on Formula One.
The starting points are the physics and chemistry labs, where new compounds and structures are tested using cutting-edge equipment. Detailed use is made of mathematical modelling, to simulate the reaction of each compound combined with each structure, in every possible set of usage conditions. An enormous amount of data is processed and compared in order to create these ‘virtual’ tyres that represent a model of the eventual finished product.
2) At the motorsport department in Izmit, Turkey, physical prototypes are built on the basis of the virtual model. Nearly 200 people work in the Formula One department at Izmit, from fitters to technicians to engineers. This is when the theory gets turned into practice: the compounds and structure are tailor-made and all the components are finally put together. A finished tyre is born, ready for testing.
3) The first physical tests take place at Pirelli’s experimental test centre in Milan, where sophisticated machines simulate every race condition and measure all the stresses to which the tyres are subjected. The tyres are accelerated to 450kph by special machines and subjected to loads that are four times greater to those they will experience during normal usage, for periods of time up to 20 times longer than usual. This simulates extremes of usage when cornering that go way beyond what can reasonably be expected.
This process of scientific evaluation recreates vertical forces superior to 1000 kilograms, longitudinal acceleration equivalent to 5G (five times the force of gravity, like a man weighing 80 kilograms pulled by a force of 400 kilograms) tread pattern temperatures higher than 150° and impacts with kerbs at 260kph: all common occurrences in Formula One. Only the tyres that survive these tests unscathed go through to the next phase of development, at the end of which data is collected to compare to the information gathered from the computer modelling. If the data from the practical tests matches the theoretical results, the tyre is then ready for the next step: the racing circuit. Otherwise the whole process starts again from scratch.
4) Once all these laboratory tests have been concluded, the tyres then get to experience a real circuit. Pirelli has carried out 13 tests in Europe and the Middle East, covering a total of 18,000 kilometres during private testing. The circuits used include Barcelona, Monza, Jerez de la Frontera, Le Castellet, Mugello, Abu Dhabi and Bahrain. The first tests took place on 19 August 2010, just three months after Pirelli was nominated as sole supplier for Formula One at the end of June. The first official tests with all the teams took place in Abu Dhabi at the end of the 2010 season, only three months after the tyres had run for the very first time at Mugello. This was an unprecedentedly short period of time to develop the tyres, as many team principals and drivers subsequently observed.
The tyres that have successfully made it through the track tests are then eligible to form part of the final selection offered to the Formula One teams for racing this year. Pirelli is supplying four slick tyres in 2011 (supersoft, soft, medium and hard) as well as two rain tyres (intermediate and wet). Each one is easily identifiable thanks to different coloured markings, which will be even more prominent from Turkey onwards.Pirelli takes around 1,800 tyres to each race, in the two compounds that have been selected in advance for each grand prix as well as a supply of rain tyres in case conditions are wet. The tyres are all made on the dedicated Formula One production line at Izmit thanks to the following steps:
The Pireli factory in Turkey.
1. Production of the shoulder and the carcass on a dedicated line. At the same time, on a parallel line, the belt and tread pattern are produced. Natural rubber, synthetic rubber and other artificial fibres are among the key ingredients.
2. The elements produced by the first two production lines are assembled on a third line, which represents the key part of the production process. All 18 of the major components that make up the structure come together to form a recognisable Formula One tyre.
3. The next step, the vulcanisation period during which the tyre is ‘cooked’, determines the definitive characteristics of the compound and structure.
4. Next up is quality control, which takes in a visual check and a scan of the tyre similar to an xray, in order to verify the integrity of the internal and external structure. The circumference and other parameters are also measured to check the uniformity of the surfaces.
5. Finally the bar code is affixed, which acts as the tyre’s ‘passport’. This contains all the relevant data about the tyre and allows its usage to be tracked from production to race. The final check is to measure the weight of the tyre. In total it should weigh about 8,5 kilograms: about the same weight as an average three-year-old child. The tyre is then ready for despatch to the next grand prix.
The Pirelli PZero in numbers:
- Over 100 elements in each tyre
- 18 structural components
- 5 hours of work needed to make each tyre
- Approximately 8,5 kg is the total weight of a front wheel and tyre
- Approximately 9,5 kg is the total weight of a rear wheel and tyre
- About 1,800 tyres are taken to each Grand Prix
- 30 laps is the average working life of each tyre in race conditions
- 450 kph is the maximum speed reached by the tyres during laboratory testing
- 260 kph is the speed at which the tyres are impacted against kerbs during testing
- 5G of longitudinal acceleration affects each tyre; 4.5G is the vertical acceleration
- 150° C is the temperature that the tread pattern is exposed to in laboratory testing
- 3 times is the increase in size of the contact patch under full aerodynamic load