Zhou Guanyu posts update after driving Ferrari's F1 challenger for key testing session

Zhou Guanyu was back in the Ferrari cockpit during a wet tire testing session at Fiorano on Thursday, June 19. The Scuderia reserve driver was logging in crucial laps for Pirelli's ongoing tire development for the 2026 Formula 1 season.

Guanyu completed a full day's work behind the wheel in a modified SF-25, designed to simulate a low-downforce environment replicating the next-generation F1 car. He posted a carousel of pictures from the day on X, where he was in action around a soaking Fiorano circuit with engineers, suited up in red. In the caption, he revealed testing tires for the 2026 season.

"Drove SF-25 today✌🏼, testing for Pirelli 2026 tyres ✅," Zhou Guanyu wrote.

Ferrari also marked Guanyu's return to their private Maranello track with their own update on their official X account, writing:

"@ZhouGuanyu24 at Fiorano 🔴 Putting in the laps at home base"

Zhou Guanyu is a product of the Ferrari Driver Academy. While he raced full-time for Sauber from 2022 to 2024, he returned to Maranello as the team's reserve driver in 2025. He now performs simulator duties, on-site backup, and testing roles, as teams prepare for the 2026 reset.

Guanyu completed 159 laps on Wednesday, just under 500km of running. The SF-25 mule car he drove was adapted to accommodate the new tire specifications and reduced downforce requirements expected from the upcoming 2026 regulations. His benchmark times included a 59.820 on slicks and a 1:07.400 on the intermediate prototype compound, made possible through Fiorano’s artificial irrigation system.

Ferrari No. 16 driver Charles Leclerc is expected to take over the test program on June 20, continuing their two-day commitment for Pirelli's wet-tire development.

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Ferrari joins Pirelli's push to prepare the 2026 F1 tire

Formula 1 pre-season testing at Sakhir Circuit in Bahrain on February 28, 2025 - Source: Getty

F1 is set for a technical overhaul in 2026, and Pirelli is preparing ahead to develop a new set of tires that suit the next-gen cars. Since the actual 2026 machines do not yet exist, the Italian tire manufacturer is relying on a combination of virtual simulation and physical mule cars to duplicate the aerodynamic loads expected under the new regulations.

At the heart of the 2026 rulebook lies a shift in downforce production. Formula 1 cars will use active aerodynamics, or X-mode and Z-mode, to alternate wing configurations for straights and corners. Alongside reduced overall downforce and narrower tire dimensions (25mm smaller at the front and 30mm at the rear), these changes have forced Pirelli to begin development earlier than usual.

Earlier this year, Pirelli ran dry-tire compound testing with Ferrari and McLaren at the Circuit de Barcelona-Catalunya using skinny-winged mule cars. These cars were fitted with reduced-drag setups and experimental tire constructions to simulate 2026-style grip. Pirelli chief Mario Isola admitted that while customized cars are not a complete solution, they are key to simulating real-world behaviour.

Lewis Hamilton (44) Scuderia Ferrari SF-25 on track during day two of F1 Testing at Bahrain-Source: Getty

Ferrari will reportedly return to Fiorano on August 4–5 after the Hungarian GP to focus on dry-weather tire development. Scuderia technical director and a long-time tire-suspension expert, Loïc Serra, will help the team understand these new compounds in detail.

Pirelli's testing program also includes Mercedes, Red Bull, McLaren, and Aston Martin, at various stages this year, sharing virtual tire models across the grid to ensure a balanced outcome.