From the moment the checkered flag marked the end of the 2019 season in Abu Dhabi on Sunday, Formula One immediately shifted its focus to the future.
The full attention of the teams is not even on the start of the 2020 season in Australia in March. They are looking instead to the beginning of the 2021 season, when radical car design regulations will take effect, including revised front and rear wings, more underbody aerodynamics — and new tires.
Those are the responsibility of Pirelli, the Italian manufacturer that supplies tires to the Formula One teams. For 2020, Pirelli will continue to refine and produce its current specification of tires that fit 13-inch wheel rims. But from 2021, teams will use 18-inch tires as part of the new regulations.
This change is intended to reflect trends in the automotive industry, in which wheel rims are traditionally wider than those used in Formula One. After all, the sport acts as a high-speed laboratory for Pirelli to refine its consumer tires.
The shift will have a profound impact on how the tires behave on Formula One cars, making it important for Pirelli to get them right.
“A development like 18 inches is a bit of an unknown,” said Mario Isola, Pirelli’s head of Formula One and car racing. “Not the size itself, because we develop 18 inches for G.T. [Grand Tourer] cars, and most of our motorsport tires are this size.
“But if we talk about the level of load stress for a Formula One car, it’s very different. We have to estimate the level of load stress and down force for the aero package that they are planning to have in 2021.”
Pirelli offers teams three compounds, soft, medium and hard. Each presents a trade-off between grip and durability that figures in racing strategies. Soft offers greater performance but wears faster and requires more pit stops; hard tires have less traction but last longer; and medium offers a bit of both.
For example, Lewis Hamilton of Mercedes used hard tires for part of the United States Grand Prix in November, where he won the season championship. Those tires allowed him to cut out one of his pit stops, saving time, but by the end of the race his teammate, Valtteri Bottas, who was running on better-performing medium tires by then, was able to pass Hamilton and win the race.
As well as shifting to 18 inches, Pirelli has also been asked to make longer-lasting tires. Under the previous regulations, it made compounds that degraded quickly, the hope being that big swings in tire performance would improve the on-track spectacle.
Another concern about Pirelli’s current tires is their sensitivity to heat. Drivers must manage them very carefully, for example by adjusting speed, to ensure that they are not too hot or too cold, keeping them within a temperature window to improve grip.
Formula One has worked with Pirelli to solve these issues in the new tires, giving targets for tire performance.
“We are trying to give them more clarity on what Formula One really needs, and I think they have been responding quite well,” said Ross Brawn, the managing director of motorsports for Formula One.
Isola has appreciated having a clear target to aim for with tire development instead of an array of input from drivers, teams and fans, all of whom have different wishes.
“All the stakeholders are asking for something different, because they have a different view on the sport and different requests,” he said.
“Now we have a ‘target letter’ where the targets or the expected targets of the product are identified and described,” he said. “It’s easier to explain to everybody that we have to follow some rules.”
The 2021 regulations were finalized at the end of October, giving Pirelli a better picture of the stresses and loads the cars will exert on its tires. But only when the new cars hit the track in February 2021 will Pirelli will get a definite answer on how the new 18-inch tires perform.
Any on-track testing up to that point will take place on modified versions of the current cars. These are very different from the models that will be used from 2021, which will produce less force.
“We have a long list of characteristics of the tire we are designing, outlining what would be the best for the future car,” said Maurizio Boiocchi, an executive vice president who oversees strategic advisory technology and innovation at Pirelli.
“We have to develop tires while they are developing cars,” he said. “But there does not exist at the moment a car which we start to develop them for.”
Despite this challenge, Pirelli can still gather valuable data by completing test runs using the early prototypes of its 18-inch tires. The company started its on-track testing program for 2021 in September, completing more than 200 laps with the Renault team’s 2019 spec car.
“It was very useful for us to take a first look at the new generation of tires and start shaping the development path that we will follow for the remainder of this year and next year,” Isola said.
“Of course, it is hard to read too much into this test as these are still very early days, but we accumulated all the preliminary data that we wanted.”
Pirelli also has simulator software and sophisticated machinery to help develop its tires. “A lot of work is done on the computer,” Isola said. “But we also have a lot of machines where we put tires to stress at a level that is a lot higher than what we have on track.”
A Formula One car averages 125 miles per hour during a race, but reaches speeds of over 200 m.p.h. Pirelli’s machines can manage 280 m.p.h.
“It’s good to be sure that we have a tire that is able to resist to this level, for example, but it’s not just the speed,” Isola said.
“It’s the load, it’s the traction, it is the stresses in all the directions, and the heat also,” he added. “That’s why for some of the machines, we have a special surface that is able to generate heat into the tire.”
Even with Pirelli’s research and development, the teams are braced for a year of learning how the new tire acts.
“Going to an 18-inch tire, a low-profile tire, it’s a big change,” said Gunther Steiner, the Haas F1 Team principal. “There will be so much learning done in the first year.”
Kate Walker contributed reporting from Milan.