Andrea Stella has no regrets about not adding more upgrades to the McLaren MCL39, warning that an F1 2026 project could be ‘heavily compromised’ with a late push this year.

While McLaren switched off development upgrades for the MCL39 this summer, the Woking-based squad is facing an increasingly tight championship fight with Red Bull’s Max Verstappen as the Milton Keynes-based squad has kept adding further developments to its RB21.

Andrea Stella: McLaren’s aerodynamics had plateaued

Red Bull’s continuous evolution of the RB21 has seen Verstappen become a genuine thorn in the side for the two McLaren drivers, with the MCL39 – Mexico aside – no longer the clearly dominant car it was during the first half of this season.

In 2025, the final year of the current chassis and power unit regulations, the rewards for swapping to development of the F1 2026 machines could potentially be far greater than pursuing further gains with a car of limited shelf life.

Not only does a team gain knowledge earlier and put itself ahead on the learning curve, but the financial regulations outlining the set budget cap each year means teams have to be wary of how best to allocate resources for each season; a regulation change requiring more of these resources than a more straightforward year-on-year evolution.

It’s for this reason that Red Bull’s steady development of the RB21 has intrigued the paddock, given the possibility of Laurent Mekies’ squad being compromised at the start of the new regulation cycle against teams that swapped full attention to next year at a far earlier point.

Certainly, McLaren has not been cowed by Red Bull’s developments, with a clear denial of any interest in switching back on any tap of development for the MCL39 despite the improved RB21.

And team boss Andrea Stella has suggested that, for McLaren at least, development this late into the current regulations would have an impact on a team’s chances for the new regulations.

“The 2026 project would be heavily compromised,” he bluntly told media including PlanetF1.com at the Mexico City Grand Prix.

“We want to win championships in the future. To win championship in the future, you need to have a competitive car.

“I think we have been very considerate in the timing of switching our full resources to 2026.

“We also have to make a technical point here; our car, from an aerodynamic point of view, was already quite mature, and, to add one point of aerodynamic efficiency like we have added more than one point when we upgraded our car around Austria, Canada and so on, it takes weeks for us to add one point of aerodynamic efficiency because we were at a plateau in our aerodynamic development.

“In 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 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 allowance and the CFD allowance. So it’s not like we have an unlimited amount of resources that we can use.

“So we need to be on the rate in the way we allocate resources this year to next year, because it comes from the same point when it comes to CFD and an aerodynamic wind tunnel testing.

“Like I said before, because we were so much in the diminishing returns, we needed to be realistic and shift our attention to 2026.

“Also, I think that, 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 focusing on 2025 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 ’25.’”

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As for how much of a compromise a team still developing for 2025 would be facing, and whether that sacrifice would be more on the manpower or wind tunnel and CFD time, Stella said, “It’s both. It’s exactly both.

“When you work in a very efficient way in a Formula 1 team, actually, you blend your manpower with the methodologies, the CFD, and the wind tunnel, such that none of them is actually a single limitation.

“You blend your working ways in a way that they become a single limitation at the same time, and that’s exactly what was the case for us.”

Until Lando Norris’ performance in Mexico assuaged some fears that the MCL39 is no longer capable of beating the RB21, Stella said that he has no regrets about how his team has tackled the allocation of resources and that he doesn’t believe McLaren switched off the tap too early.

“Not at all because it’s not like, if I spent three weeks more on the 2025, I’m gonna add a tenth of lap time. We were just plateaued,” he said.

“Actually, to produce the upgrades that we took to the mid of the season, it was a huge undertaking. We were like, ‘should we actually finalise?’, because we were struggling to improve what was already a pretty mature project.

“So you have seen how many cars actually attempted to develop, and sometimes things went the opposite direction. This is because it’s very sophisticated aerodynamics.”

With little headroom for further improvement on the MCL39, Stella said he suspected Red Bull’s improvements have been more about fixing problems with its car, rather than honing additional performance.

“Maybe one day we can talk about like the specifics of the technicality and the difficulties of developing, I think it’s much easier to develop when you have some specific problems,” he said.

“For instance, for Red Bull, they 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.”

As for Red Bull, which hasn’t backed off from adding further tweaks to the RB21 as Verstappen remains in contention for a potential fifth consecutive title, team boss Laurent Mekies has been open about the fact there is likely to be a net cost to Red Bull to the RB22 for next year.

However, in his eyes, this doesn’t necessarily mean something negative, as Mekies has explained the team has needed to validate its understanding of correlation between its own simulations and the real world; this is an area Red Bull has struggled with over the past two seasons.

“From a Red Bull perspective, and without looking at the other guys around, I think it was, and is, very important that we get to understand if the project has more performance,” Mekies said in Singapore.

“It’s important that we get to the bottom of it, because we will elaborate next year’s project, even if the regulations are completely different, with the same tools, with the same methodology.

“It’s very important that we validate, with this year’s car, that our way of looking at the data is correct, our way of developing the car is correct, that produces that level of performance – that will give us confidence in the winter for next year’s car.”

Confirming that Red Bull is understanding what’s being produced and having the real-world performance match up with simulations does mean having to throw some resources at the RB21 at a point where most of the focus across the grid is firmly on next year, but Mekies said this opportunity cost is the right level of risk, in his eyes.

“So of course, it comes at a cost, undoubtedly, to the ’26 project,” he said.

“But we feel it’s the right trade-off for us, without judging what the other guys are doing.”

Additional reporting by Elizabeth Blackstock.

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