Adrian Newey suspects that inexperience among Red Bull's technical leadership following his departure was a factor in the team's Formula 1 decline last year.
The F1 design genius announced in April he was leaving the squad and, although he remained present at races after that, he was removed from direct involvement in technical matters.
His exit, eventually followed by news that he would join Aston Martin in 2025, coincided with Red Bull's previous dominance of F1 being wiped away - as McLaren, Ferrari and Mercedes all made steps forward to win races.
It took Red Bull until the latter stages of the year to get on top of the handling and balance problems of the RB20, with a victory for Max Verstappen in Brazil helping him on his way to capturing the drivers' championship.
While the development progress of its rivals was an element in a change of the competitive picture, what was less obvious was why Red Bull's own form fell away so much and both Verstappen and team-mate Sergio Perez struggled.
Speaking in a wide-ranging video interview with Auto Motor und Sport, Newey was asked for his best guess as to why Red Bull had not been able to maintain its strong start to the 2024 season.
His response was that he believed that warning signs about Red Bull's car getting more difficult to drive were not being heeded, and that it took the squad a bit too long to react in the right way without him.
"From what I could see, the car was already, the '24 car, and through the very last stages of '23 as well, I would say, starting to become more difficult to drive," said Newey.
"And of course that suited Max: [he] could handle that, if you like. It didn't suit him, but he could handle it. Checo [Perez] couldn't. So we also started, through '23, to see more of a difference in performance between the team-mates, Max and Checo.
"That [characteristic] carried into the first part of '24 but the car was still quick enough to be able to cope with it.
"It was something I was starting to become concerned about, but not many other people in the organisation seemed to be very concerned about.
"And from what I can see from the outside, but I don't know, the guys at Red Bull, and this is no criticism, but I think they just, perhaps, through lack of experience, kept going in that same direction.
"And the problem became more and more acute, to the point that even Max found it difficult to drive."
Missed characteristics
Newey's perception of the first hints of trouble appearing at the end of 2023 are in line with what Red Bull technical director Pierre Wache pointed to over the winter.
Speaking to The Race, Wache said that the team, in its quest to make the RB20 a good step forward, had not paid big enough attention to some behaviours that had emerged with its predecessor.
"We missed some characteristics of the car," he said. "I wouldn't say we didn't spot it, but it was not highlighting a massive loss of performance previously.
"During the season we saw this type of characteristic which was seen, but not highlighted, as a big issue. But when we reduced the downforce for Monza it really highlighted the problem massively."
The demands of Monza, where cars run in low-downforce spec and off the ground because of kerbs, exposed a specific weakness of the RB20 in how it operated at a high ride height.
Verstappen is understood to have spotted on the data how the shift in aero balance towards the rear on corner entry in this configuration was much worse than it had been with its 2023 car - so was probably a cause of the mid-corner understeer problems that the squad had been suffering from.
It proved to be the eureka moment in helping Red Bull get a better understanding of what was wrong with its car, and helped it put in place a revised upgrade package that resulted in the gains that came from the United States GP in October.
Wache added: "The concept was more or less a philosophy. More and more when you extract performance you start to create some other characteristics. These are highlighted at very low downforce, high ride heights, as suddenly the driver cannot drive the car."
In his interview, Newey explained how the current generation of cars were especially difficult to develop and ensure that they perform consistently at different ride heights without triggering balance complications.
"A ground effect car which doesn't have sealed skirts like the old sliding skirt cars, is always going to be very susceptible to aerodynamic instabilities," he said.
"You now start to generate these very low pressures under the floor, but you have all this leakage coming in from the side, and that creates, potentially, some quite strong losses and problems as you get closer and closer to the ground.
"But equally they're a good way of creating downforce. So you're always trying to trade downforce versus consistency through [the right height range]. It's a difficult problem."
