https://www.auto-motor-und-sport.de/for ... o-schwach/
"Why was Ferrari so weak?"
Excerpt (translated):
The third sector of Barcelona?
You can't overestimate the influence of the top speeds on the lap time. The decisive factor is what happens in the corners. And that brings us back to the subject of slow corners. The words of Valtteri Bottas still ring in our ears during the tests, when Mercedes was still poking in the fog. "The car clearly got better in slow corners. But in the fast corners we still feel an instability in the rear." Since Barcelona mainly consists of long and fast corners, this deficit was disproportionately significant there. When Mercedes now says that they were enlightened on the last day of testing, it's very likely the problem in the fast corners. This has obviously been solved by changing the aero balance.
Flashback to Barcelona. There is an interesting detail from the comparison of Vettel's and Hamilton's fastest laps that could give an indication of why Ferrari was worse than expected in Melbourne. And that it may not only have to do with the set-up, as Ferrari wants to tell us. Let's recall Barcelona for a moment. The first sector consists of three fast corners. The second consists of two slow corners, one medium fast, one fast corner and one straight. The third consists of five slow corners, one medium fast and one fast. And now the two top laps in sector comparison (see the graphic on the AMuS page)
Notice anything? Hamilton took three tenths of a second off the Ferrari in the third sector, whose corners are most similar to those in Melbourne. So already in Barcelona, where the Ferrari was still in shape. That's a lot of wood and suggests that even a well-balanced Ferrari has a problem in this area. Ferrari made up for the lost time in the first two sectors, where the corners are mostly fast and have long radii.
There are no such sectors in Melbourne. The last 31 seconds of the lap are the closest to Barcelona, and that's where Ferrari lost the least time on Mercedes. By the way, the Mercedes and Ferrari were absolutely identical at top speed and speed measurement on the finish line in Barcelona. Which leads to the conclusion that the car is relatively identical in terms of power and drag.
Suspension travel and aerodynamics
In Melbourne, the slow corners are what count most. Seven of the 16 corners are under 160 km/h. Mercedes was already in a good position. If the silver arrows have not lost anything on Ferrari thanks to the homework between the test drives and the first race in the fast corners, and Ferrari could not solve his problem in the slow corners, a good lead is quickly achieved.
Possibly Ferrari knew about his weakness and messed up the setup more and more to recover the weakness. Maybe Ferrari could have learned something from Red Bull, who also turned in circles with the set-up, but jumped on the right train at the last minute. At first the suspension was trimmed to hard and harder and the lap times became slower and slower. It was only when they went softer that Red Bull was able to escape the trap.
It must worry Ferrari that there are more slow than fast corners in Bahrain as well. That mechanical grip is as important as good aerodynamics. In the first reflex one would say that Ferrari should also allow more suspension travel. But that's not always easy. Maybe the aerodynamic platform of the SF90 only works in a small window at ground clearance. That would be a serious problem, because it is not easy to solve. Because of its front wing concept, Ferrari has to drive a lot of pitch in order to get back the downforce via a deep wing, which one normally loses with this arrangement of front wing flaps.
Mercedes' doubts about the front wing philosophy of Ferrari, Alfa-Sauber, Toro Rosso, McLaren and Haas were centered around the question of how to get the downforce back on the front axle. Sky expert Martin Brundle reported from the track that the Ferrari had shown too much understeer in the slow corners. In an effort to stop this, the engineers may have overstepped the mark. They made the rear end weaker, but paid for it with poorer traction and more tyre wear.
The Mercedes engineers nevertheless believe in a one-off slip and attribute it to the Ferrari's unusually heavy tyre wear.
"In Barcelona, Ferrari, we and Haas were on about the same level. In Melbourne the Ferrari was a different car. This is shown by the pictures taken by the onboard camera. The thing that drove on rails in Barcelona was suddenly unstable in Melbourne. The only differences were the track characteristics, the temperatures and the wind."