Hamilton and Leclerc head to Mugello as Pirelli locks in 2026 rubber; Grosjean set for emotional Haas return
Ferrari will roll the red cars into Mugello on Friday with both Lewis Hamilton and Charles Leclerc sharing duties in a Pirelli tyre test that moves F1 another step toward its 2026 reset.
The Scuderia’s mule car — a heavily modified SF-25 built to mimic next season’s aero loads — will be in action as Pirelli carries out what it calls final assessments of the harder end of its 2026 compound range. Expect long runs, data hoovering, and plenty of mileage around a circuit that punishes tyres in all the right (and wrong) ways.
Mugello is as old school as it gets: fast, flowing, relentless. Perfect for understanding how narrower tyres will behave once the sport flips the switch on its new rulebook next year. Those tyres will shrink 25mm at the front and 30mm at the rear, a change intended to reduce drag and work in concert with 2026’s headline tech: active aerodynamics, 50% hybrid power and fully sustainable fuels.
Ferrari has been an enthusiastic partner in that programme, previously trialling a DRS-style device on the front wing of its mule to replicate active aero. The aim is to help Pirelli map out how these tyres react to cars shedding drag on the straights and cranking downforce back on in the corners — a fundamentally different load profile to what teams have been designing around since 2022.
For Hamilton, it’s another useful day of Ferrari seat time that doesn’t show on a Sunday results sheet. For Leclerc, it’s home turf and an early look at the direction of travel for a ruleset that will define the next era of his peak years. Between them, the pair will alternate in the cockpit as Pirelli signs off its hardest compounds before winter manufacturing ramps up.
Ferrari’s Mugello week is a two-parter. Ahead of the Pirelli running, the team is also conducting a TPC (Testing of Previous Car) day with its 2023 chassis, giving Arthur Leclerc and Zhou Guanyu mileage under the watch of the race team. Regular reserve Antonio Giovinazzi is tied up in Japan for the World Endurance Championship’s 6 Hours of Fuji, so the supporting cast gets a rare day in the spotlight.
They won’t be the only ones on track. Haas is making the short trip with its 2023 VF-23 for a feel-good story: Romain Grosjean climbs back into an F1 car for the first time since 2020. It’s more than a demo. The American team has leaned into TPC running as a development tool this year, and Grosjean — who raced for Haas from 2016–2020 — slots neatly into a familiar setup with familiar faces.
“I’m incredibly grateful to Gene Haas and to Ayao Komatsu,” Grosjean said, admitting he can hardly believe it’s been almost five years since his last F1 lap. “To come back and have this outing with my old team is truly something special.” He’ll wear the helmet his kids designed for what should’ve been his final F1 race in Abu Dhabi 2020, a goodbye that never happened after his fiery Bahrain crash brought his grand prix career to an abrupt halt.
Komatsu, now Haas team principal but briefly back on the headset as race engineer for the day, called it “only fitting” that Grosjean’s return comes with Haas. The pair worked together across Grosjean’s entire F1 stint, from Lotus to the early Haas years, and there’s real affection in the reunion. “Knowing Romain as I do, I know he’ll want to give it his all,” Komatsu said. “We’ve talked about making this happen for a long time.”
Beyond the sentiment, there’s substance at Mugello. Pirelli needs to validate construction, temperature windows and wear rates for tyres that will live on different-sized rims and cope with cars that will shed and recover downforce at the push of a button. Teams, meanwhile, are quietly collecting their own clues: how the car balances on narrower rubber, what the braking stability looks like, how much front-end bite returns when the active aero reengages.
Ferrari’s choice to split the day between its lead drivers is telling. The 2026 cars will not simply be a lighter-straight-line, heavier-cornering version of today’s machines; they’ll demand a different driving rhythm. Getting both Hamilton and Leclerc tuned into that early — and making sure their feedback dovetails — is exactly the kind of groundwork big teams want now, while the drawing boards are still pliable.
It’s also a reminder of how compressed the runway is from regulation theory to racing reality. By late autumn, Pirelli will have to lock profiles and constructions so factories can tool up. The only way to do that with any confidence is with representative loads, aggressive circuits and drivers who can feel the nuance. Mugello ticks all three.
So yes, Friday is a test day. But it’s also a teaser. A flash of what’s coming when F1 flicks to 2026: lighter on tyre width, heavier on systems to manage them, and a very different kind of dance between car, driver and corner. And for Grosjean, for one day at least, it’s a dance he gets to join again.
