Mario Isola, director of Pirelli Motorsport, clarifies the technical factors that allow one team to achieve the optimal operating window for their tires compared to another. Comments from the paddock suggest it depends on the tires, but overheating is actually related to the cars.
Within this “window” lies the difference between success and failure. In Formula 1, it has become standard practice to reference the “operating window” in discussions. Whether it’s a driver or an engineer, the concept is a key variable in determining if work is progressing in the right direction.
Setups are designed to hit the “window,” cars are engineered to facilitate this goal, and drivers adapt their driving styles to operate within this range.
To better understand the science behind this “window,” Motorsport.com asked Mario Isola, director of Pirelli Motorsport, to provide a straightforward explanation of the technical concepts that dominate team briefings: “You have to start with the tread compound, the part of the tire that touches the asphalt, where contact generates grip based on temperature,” Mario Isola explained.
“When a driver goes out on track, there is an initial warming phase where grip is reduced due to low temperature. As the tire rotates, it heats up, a process commonly called the warm-up, until it reaches a temperature at which the compound delivers maximum grip. If this threshold is exceeded, the tire overheats, and grip is lost. So where do drivers always want to be? Obviously, at the peak.”
The ability to hit the window—defined by the minimum and maximum temperatures where the tire delivers optimal performance—depends on many factors. Often, people (especially drivers) think the tire is the cause, but it’s actually an effect. The window is not solely determined by tire characteristics but is the result of how a car uses the tires.
The size of the window varies with different compounds, but there are significant differences between cars. Suspension design is a key variable, but aerodynamic load plays a crucial role, as it determines how much the tire is pressed against the asphalt: “If the contact patch is larger, grip improves, although it’s not the only factor to consider for performance,” Mario Isola emphasized. “Distributing the contact surface more evenly increases efficiency and reduces overheating because heat is dissipated over a larger area. So it’s fair to say the team defines the window with their car.”
When Pirelli became the sole tire supplier for Formula 1, one of the requests from teams was to increase the window’s range, initially defined as a 3% reduction in grip variability. However, that range quickly became less relevant: “A 3% grip difference today equates to about one second per lap,” Mario Isola noted, “an enormous value given the current level of competition in Formula 1. We’ve worked extensively to achieve realistic conditions in our indoor tests, and now we can simulate different types of asphalt, temperatures, and conditions.”
The latest generation of tires has improved in warm-up times (a faster process now) and stabilizes to ensure a broader optimal operating window with a more gradual entry and exit from the window. “The classic example is overheating,” Isola explained. “When a driver exceeds the window, they feel a loss of grip and worry they can’t bring the tires back into the optimal range. Now overheating is more gradual compared to the past, allowing drivers to notice rising temperatures early and manage the situation. To modify the operating curve of the tires, we worked on the chemistry and ingredients of the compounds, achieving slightly wider and flatter operating curves.”
Pirelli’s challenge is complex, further complicated by the need to provide the best compromise for ten teams.
“In a single-supplier scenario, that’s how it is,” Mario Isola admitted. “In championships where tire suppliers compete, the focus is on the equipped team. It’s a scenario we know well from GT championships. But in today’s Formula 1, the team must design the car according to the tire characteristics. For this reason, teams are asking us for more data earlier and earlier. We’re already at a stage where they’ve requested information for 2026 projects!”
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