Why McLaren feels halting 2025 F1 development was the right...

McLaren has explained why it still backs its decision to halt development of its 2025 F1 challenger early, leaving the door open for Red Bull to take the upper hand.

McLaren made 2024's best car better with an innovative approach over the off-season, picking up where it left off as F1's dominant team before the summer break. It further enhanced its car with significant upgrades in Canada, Austria and Britain, but after its Silverstone floor overhaul the Woking-based team has fully shifted focus to 2026, other than finding some minor efficiency gains with its Monza wing and floor as well as some other track-specific items.

McLaren's early season advantage was enough to canter to a second consecutive constructors' title by Singapore, but at the same time it also started getting caught be a reinvigorated Red Bull squad, which has brought another new floor to its RB21 at the Mexico Grand Prix.

That has allowed Max Verstappen to mount a late title challenge as he closed the gap to leader Oscar Piastri to just 40 points with five rounds remaining, but McLaren team boss Andres Stella says there are no regrets over its approach because it started running out of development headroom with its current car compared to the rich vein of development it is hitting with its 2026 project.

"The 2026 project would be heavily compromised," Stella said when asked what the impact would have been of continuing 2025 development. "We have been very considerate in the timing of switching our full resources to 2026.

"From an aerodynamic point of view, our car was already quite mature. It takes weeks for us to add one point of aerodynamic efficiency because we were at a plateau in our aerodynamic development.

Andrea Stella, McLaren

Photo by: Simon Galloway / LAT Images via Getty Images

"On the 2026 car, every week we add a lot of downforce. So that's where, with the best information you have available, you have to make a call. We were so much in the diminishing returns, we needed to be realistic and shift our attention to 2026."

If anything, McLaren's decision making was made more straightforward by F1's Aerodynamic Testing Restrictions, which limit wind tunnel and CFD allowance based on how successful a team has been in the preceding six-month period.

As such, McLaren has had the least development time available out of all 10 teams: "We also don't have to forget that by being the champions, we are the most restricted by the regulations in terms of the wind tunnel and CFD allowance. So it's not like we have an unlimited amount of resources that we can use," Stella added.

F1 Aerodynamic Testing Restrictions July-December 2025

Position

Team

Multiplier

WT Runs (#)

Wind On Time (Hrs)

Wind Tunnel Occupancy (Hrs)

Geometries (#)

CFD Solving (MAuh)

McLaren

1400

Mercedes

1500

Ferrari

1600

Red Bull

1700

Williams

1800

Haas

1900

Racing Bulls

100%

2000

Aston Martin

105%

2100

Sauber

110%

2200

Alpine

115%

2400

Cadillac

115%

2300

Stella also pointed out that in contrast with McLaren's development plateau, Red Bull initially hit significant trouble running its car in the right set-up window, with the team only recently finding a way to run at the optimal ride heights without compromising downforce and car balance, and therefore having more performance to find than McLaren at this late stage of the regulations.

He also suggested Red Bull might have been happier to compromise 2026 because "they might have other issues", likely hinting at the Milton Keynes-based squad introducing its own in-house power unit for the new regulations.

"When we look at Red Bull and when we consider some of the complaints they had at the start of the season, perhaps they had more margin to develop efficiently, focussing on 2025," he added. "And perhaps they are happier to give up a little bit of the 2026 because they might have some other issues for 2026 whereby they say: 'Let's focus on 2025.'"

Red Bull brought its latest floor development to Mexico as Max Verstappen chases Oscar Piastri and Lando Norris in the drivers' championship

Photo by: Filip Cleeren

As such, McLaren would not have done anything differently in hindsight, even if its drivers Piastri and Lando Norris may end up missing out on the drivers' title.

"Not at all, because it's not like if I spend three weeks more on the 2025, it is going to add one tenth of lap time. We were just plateauing," Stella added.

"Actually, to produce the upgrades that we took at the middle of the season, it was a huge undertaking. We were like: 'Should we actually finalise [the parts]?' Because we were struggling to improve what was already a pretty mature project.

"I think it's much easier to develop when you have some specific problems. Red Bull, for instance, talked at times of struggling to rebalance with the front wing when they were using big rear wings. Then it's easier to find lap time because you are effectively fixing something rather than trying to improve something that already works well."

Photos from Mexican GP - Practice

Mexican GP - Friday, in photos