If there is one element that characterises Formula 1's current era, it may well be the unpredictable form curves that fluctuate more than they did before 2022.
We have seen teams make giant performance leaps over the past few winters and throughout seasons, including McLaren, RB and Aston Martin.
But on the flip side, some teams have also been knocked back by upgrades that didn't deliver or induced secondary issues on the car.
Two of the aforementioned teams, Aston Martin and RB, are among the squads that have seen their progress stunted by recent development setbacks.
Ferrari, which also made impressive race pace gains compared to 2023, has had to take its most recent batch of upgrades off its SF-24 because it induced bouncing in high-speed corners and has reverted to a specification from two months ago.
"We have basically the same car as in Imola and since Imola everyone has upgraded, probably added two tenths to the car and we have had to revert," said Carlos Sainz. "We have lost two or three months of performance gain in the wind tunnel or performance we could have added in these three months, so clearly we haven't taken the right calls recently."
RB similarly had to take most of its Barcelona upgrades off, including the floor, and took a hit in the form table as a result.
Meanwhile, Aston Martin's relative lack of progress in recent weeks has also seen it slip down the order, leading to a frustrated Fernando Alonso.
Why are teams struggling with upgrades?
It is no news that these ground-effect dominant cars have been hard beasts to tame. Just ask Mercedes, which has been in the doldrums for two years before finally finding the right answers to make its cars regular challengers rather than "divas" that were unpredictable to drive.
With these cars, increasing performance is not as easy as just whacking aerodynamic load on and pray for the best, hoping downforce will solve most of the handling issues of the car.
More than ever, developing a current car is a game of compromises, with cars that perform well in high-speed corners often paying the price in low-speed corners and vice versa.
Developing a car that is well balanced across various corner types and speed is considered the holy grail, and while a lot of attention has gone to the floor area, the front wing and suspension set-up all play a part in having a car that has a wider operating window.
The low and stiff rides of these cars have also made bumps and kerbs a bigger factor. The simulation tools teams use are extremely advanced, but even those can't simulate every variable a real-world environment throws at a car.
We have seen designers being taken for a spin by 2022's crippling porpoising issues and some teams, like Ferrari, have seen bouncing return as an unwanted side-effect of a new floor design. Even Red Bull, which dominated the past two championships, still has a car that struggles for performance over the bumps, and that issue has bitten it hard on circuits like Singapore and Monaco.
"The correlation on the downforce is okay, but it is still a question mark for everybody," said Ferrari team boss Fred Vasseur. "It is quite difficult to have correlation because you don't have bouncing in the wind tunnel. You can have more bouncing with this part than another one but to know if it will have a negative impact on performance is another story."
An additional factor is the ever-narrower scope of upgrades teams are now chasing midway through the third year of stable regulations. The time of finding tenths of a second with each upgrade is over. As performance converges and the development curves have flattened out, we are talking about parts that produce half a tenth here and there. The smaller the gains, the harder it is to validate them and filter through the noise.
Why are upgrade misses more costly now?
The complexity of these cars is such that when an update doesn't deliver or leads a team up the wrong path, it takes time to analyse as you can't solve a problem you don't understand. Not only does it rob a team of expected performance gains its rivals do manage to make, but it also delays the next upgrades as teams might have to re-think months of work and explore different direction.
"It's a double negative effect," RB team principal Laurent Mekies told Motorsport.com. "Not only did you not pocket the advantage you wanted, but you also have to delay the next one until you actually understand what's going on."
Another reason why the plight of Ferrari, Aston and RB has been so pronounced is also a factor of how much the grid has closed up. At the Austrian Grand Prix a mere 0.798s covered the entire 20-car grid in Q1, and in Canada 0.021s was the difference between pole and the second row.
Against these tiny margins, it doesn't take much for a less-than-optimal upgrade to set a team back many positions. RB's drop was quite dramatic as its car was actually slower with its Barcelona upgrades than it was without it. But even with less extreme examples, Alonso just missed the Q3 cut-off in Barcelona by a whisker, with RB's Daniel Ricciardo befalling the same fate in Austria.
It's therefore also important not to overreact to these fluctuations, as two or three tenths can be the difference between looking like a genius or a village idiot, neither of which is fair.
But when teams do get it right, fast-tracking an update one or two races earlier can be a huge boost even if the performance gain is relatively small.
"It's a time to market business," said Mekies. "Last minute, not taking the time to compare because you just want to move on and go fast.
"Sometimes you fall and that's exactly what happened in Barcelona. We put the upgrade on both cars and it was very difficult to understand how to react, and then we took the time to pause in Austria to make the right comparisons, even though it was a sprint weekend.
"Of course, you will say: 'Why don't you do [the back-to-back test] all the time? Why you don't take all the time you need?' Because it's a time to market business and if you are faster than the other guys with the same update, you will actually get more out of them.
"But it's good for the team to have that high-risk mindset. It's a highly competitive business and that's what we want the company to do."
Is short-term pain the way out?
In Ferrari's case, it conducted those back-to-back experiments in British Grand Prix free practice. While there was some short-term pain as it compromised the weekend of Sainz and Charles Leclerc, Vasseur hoped there would be a long-term gain as the Scuderia now understands what it needs to do.
"It is very difficult as a team to compromise or sacrifice Friday sessions because it means you put yourself in a tough situation, but it was the right call to do it," said Vasseur.
"It is difficult to say after the [poor] result but we did a step forward. We have a better understanding of the situation on Sunday evening than on Friday morning. This is encouraging for the rest of the season."
