vol 8, issue 3

Sports technology - F1 tyres

11 March 2013
By Mark Venables
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Pirelli’s new tyres

Pirelli’s six F1 tyres, colour coded for easy on-track recognition

F1 car graphic

The composition of the tyres has been the cause of much controversy in F1 over the years

When the Formula One season begins in Australia the 24 cars will test the limits of Pirelli's new tyres.

The humble black rubber tyre may seem like an afterthought amidst the plethora of high-tech innovations that sit under the monogrammed skin of a modern Formula One car, but they are crucial to the overall performance. After several years of Formula One tyre-wars, in which Goodyear, Bridgestone and Pirelli vied to produce the fastest tyres, the sport's governing body, Fédération International de l'Automobile (FIA), decided that better control was needed and opted for a single tyre-supplier. Since 2011 that has been Italian manufacturer Pirelli.

"Tyre performance is a crucial part of the overall performance of the car, because it's what connects the car to the ground," Paul Hembery, Pirelli motorsport director, says. "There are more time gains and losses to be made in tyre performance than in more or less any other area.

"It's not just the performance of the tyre itself that is critical to a race outcome this year; it's also the strategy on which the tyre choices are based. It is down to the teams to get the most out of them by matching the characteristics of the tyres and the set-up properly, and using the right tyre at the right time.

"What the right time is will depend not only on the meteorological and track conditions but also on what everybody else is doing."

Seven drivers stepped up to the winner's podium in 2012, a record for the sport, and the aim is to make this year's action even closer. In order to achieve this, the compounds have once again been made softer, as they also were last year.

"All the constructions and compounds are new - in fact, these are probably some of the biggest changes that we've introduced since entering Formula One in 2011 - but at the same time I think the teams will have some idea of what to expect from us this year," Hembery adds. "There's a more rapid warm-up and more temperature going into the tyres, because they are working harder with a bigger footprint in cornering. We're trying to bring back some degradation, because last year we actually had negative degradation, with just one pit-stop. So this year's tyres will be a little more extreme.

"The compound plays an important role, but tyre wear is also heavily influenced by car, weather and circuit characteristics, so it's never easy to draw firm conclusions as far as drivers are concerned. Unlike all the other parameters, drivers are subjective so it depends from weekend to weekend depending on their feeling at the time.

"If there wasn't that variation, we'd end up with the same driver and car package winning every race. And that certainly didn't happen last year, although it's clear that a driver who manages his tyres carefully will be more successful than one who takes a consistently aggressive approach. That applies to every aspect of the car though."

The basic tyre regulations for the 2013 season have stayed unchanged from last year, with each car allowed to have 11 sets of slick tyres over the course of every race weekend - six sets of the harder and five of the softer compound. For each race, Pirelli will nominate two out of the four available dry compounds in advance: one softer compound and one harder compound. At the start of the race the top-ten cars must be fitted with the tyres with which the driver set his grid time.

"It's quite a tricky decision deciding which tyres to bring to each race as there are a huge number of factors to consider, ranging from how abrasive the track surface is, to the forces going through the tyres, to the likely weather conditions, to the fundamental question of what exactly we all want to achieve from the nominations that we make," Hembery explains.

"In the end it's always going to be a compromise as we have 12'different cars and potentially 24'different driving styles, but our tyres have to work just as well under every set of circumstances. So it's a question of best matching the characteristics of the tyres that we choose to the overall set of characteristics of the race in question."

Research & development

There are 150 research engineers working exclusively on F1 tyres at Pirelli's motorsport base in Milan. "Developing a new Formula One tyre is an extremely complex process," Hembery says. "Before a tyre takes to the track, the initial research is done through mathematical modelling and computer-aided design. Then, if the results are what we expect, we move on to producing an actual tyre that gets tested extensively on track. In terms of the way we approached it, we defined the tyre construction first - the way that the tyre is made - and then moved on to the basic compounds, which define the characteristics of the tyre. After that it was fine-tuning to achieve exactly the sort of behaviour that we wanted out of the tyres."

At the motorsport factory in Izmit, Turkey, physical prototypes are built based on the virtual model developed at Milan, turning the theory into practice. In Izmit, there are two parallel production lines. One line makes the shoulder and the carcass of the tyre. At the same time, on a parallel line, the belt and tread pattern are produced. The elements produced by the first two production lines are assembled on a third line. The barcode, which acts as the tyre's 'passport', is affixed to the tyre. This contains all the relevant data about the tyre and allows its usage to be tracked from production to race.

The next step - the vulcanisation period, during which the tyre is 'cooked' - determines the characteristics of the compound and structure, also sealing in the barcode.

Race Tyre System

In the modern world information is king and Pirelli has developed an integrated computer system to collect data during tests and races. The Race Tyre System (RTS) allows engineers to monitor the performance, wear and evolution of each tyre when it is out on track.

The system links the cars, the computer screens of the Formula One teams' engineers' and a tablet carried by each of Pirelli's tyre engineers to both a local server and a central server based in Pirelli's Milan headquarters.

Once the tyre has reached the circuit and is mounted on a wheel, the RTS collects all the information about the fitting phase and optimal tyre pressure range when the tyre is first fitted to the rim. Other information stored includes the weight needed for balancing the tyre, as well as the dimensions and weight of the tyre when fitted.

When out on track, the car sends telemetry data relating to tyre pressures, temperatures, wear and degradation. This season the RTS can analyse tyre performance over a single sector and prescribed split times. The system is also linked to a system that can analyse all the telemetry data received by the cars. This system combines all the data and provides very useful averages to the teams, without disclosing any confidential information.

When tyres go wrong, as they did at the US Grand Prix in Indianapolis in 2005, it can be disastrous for the sport: the top teams boycotted the race because they felt that the tyres supplied by Michelin were dangerous; only the six Bridgestone shod cars competed. "This is Formula One so we have very demanding customers," Hembery says. "But it is ironic that at the start of the year some people thought our tyres were too radical - and then the teams got to grips with them so quickly that by the end of the year the same people said we were too conservative.

"It's inevitable that in a sport that operates with so much state-of-the-art technology and brilliantly talented people, the teams will get on top of any innovation sooner rather than later. That's been the challenge in many ways: we constantly have to keep on reinventing ourselves to provide something new."

When the grid assembles for the first race of the season around Melbourne's Albert Park, the eyes of the world will be on the cars and drivers, but spare a thought for the rubber that allows the multi-million pounds machines to hug the tarmac.

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Tyre compounds: Meet the contenders

Supersoft (red)

The P Zero Red supersoft was the only tyre last year to remain unchanged from 2011, but for 2013 it is all new with a softer compound designed to increase performance and degradation. The warm-up has been made even faster this year.

 

Soft (yellow)

The P Zero Yellow soft is just over half a second per lap slower than the supersoft, but it is still softer than the equivalent compound last year. However, it has a high working range that makes it suitable for an extremely wide range of conditions.

 

Medium (white)

The P Zero White medium has a lower working range, making it the ideal choice for circuits that are slightly less demanding or have lower ambient temperatures.

 

Hard (orange)

The P Zero hard tyre becomes softer - closer to last year's medium. The working range has been changed compared with last year, being higher and very similar to the soft.

 

Intermediate (green)

The Cinturato Green intermediate has a new rear construction, but the tread pattern remains the same. However, modifications made to the rear tyres in particular have enhanced it.

 

Wet (blue)

The Cinturato Blue wet benefits from a new construction. The rear tyres have been redesigned to offer more progressive traction and reduce snap oversteer.

F1 tyre: It's a numbers game

Pirelli is the fifth-largest tyre company in the world

50 

Number of times per second a P Zero tyre rotates at full speed

52 

Number of Pirelli personnel that travel to each F1 race

130 

Peak temperature reached by the P'Zero compounds in centigrade

450 

Speed in kilometres per hour that Pirelli tyres are accelerated up to during laboratory tests

1,800 

Approximate number of tyres supplied for each F1 race

4,500 

Approximate number of patents held by Pirelli all over the world

15,000 

Space in square metres covered by Pirelli's Izmit factory, where the F1 tyres are made

36,000 

Number of kilometres carried out by Pirelli in private testing, approximately

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