Formula One's second day of three preseason tests is underway at the Bahrain International Circuit.
It is the only track time allocated to teams ahead of the Bahrain Grand Prix on March 28.
Mercedes' difficult start to testing continued on the second morning in Bahrain when Lewis Hamilton spun while pushing on a quick lap in the new W12. He lost the rear of the car at Turn 13 and ended up in the gravel, where his car became beached. In order to retrieve the Mercedes from the gravel, the session was red flagged.
Something akin to normal service resumed in the afternoon as Valtteri Bottas set the fastest time for Mercedes in the final hour of the session. However, he was only 0.1s clear of Pierre Gasly in the AlphaTauri, with both drivers using the softest tyre compound. Fuel levels and engine modes remain unknown, making it hard to draw any conclusions from the headline times.
Nicholas Latifi and Carlos Sainz also spun earlier in the session after they lost control in separate incidents between Turns 7 and 8. High winds cross the circuit in that area and were likely to blame. Both drivers kept their car out of the barrier and kept running.
Red Bull appeared to attempt a race simulation in the afternoon, indicating the team is nicely advanced in its preseason schedule, while offering a glimpse of its potential performance at the opening race in Bahrain in two weeks. However, Sergio Perez parked the car during the final stint.
A second red flag was caused by Perez's engine cover coming off on the pit straight as he moved out of the slipstream of Nicholas Latifi's car and the change in air pressure lifted the bodywork off. Debris was left all over the straight, resulting in a stoppage in the session.
Sebastian Vettel was limited to just six laps after a gearbox problem on his Aston Martin. The new AMR21 uses a 2020-spec Mercedes gearbox, but it is unclear if the issue is in anyway related to the problem suffered by the works team on Friday. He managed to return to the track but was limited to just 10 laps by the end of the morning, with teammate Lance Stroll adding 70 laps in the afternoon.
Fernando Alonso completed his first day back as a full-time F1 driver after a two year absence from the sport. He had a productive day, with 140 laps including a mix of short and long runs.
Times (with one hour remaining)
1. Bottas - Mercedes - 1:30.289 - 56 laps (C5)
2. Gasly - AlphaTauri - 1:30.413 - 86 laps (C5)
3. Stroll - Aston Martin - 1:30.460 - 71 laps (C5)
4. Norris - McLaren - 1:30.586 - 52 laps (C4)
5. Giovinazzi - Alfa Romeo - 1:30.760 - 125 laps (C5)
6. Leclerc - Ferrari - 1:30.886 - 73 laps (C5)
7. Latifi - Williams - 1:31.672 - 132 laps (C4)
8. Perez - Red Bull - 1:31.682 - 117 laps (C2)
9. Ricciardo - McLaren - 1:32.215 - 52 laps (C3)
10. Alonso - Alpine - 1:32.339 - 128 laps (C2)
11. Tsunoda - AlphaTauri - 1:32.684 - 57 laps (C4)
12. Schumacher - Haas - 1:32.883 - 88 laps (C4)
13. Sainz - Ferrari - 1:33.072 - 56 laps (C3)
14. Mazepin - Haas - 1:33.101 - 76 laps (C4)
15. Hamilton - Mercedes - 1:33.399 - 58 laps (C2)
16. Vettel - Aston Martin - 1:38.849 - 10 laps (P)
(Tyre compound in brackets. P = Prototype, which is equivalent to C3)
Who's looking quick?
It's easy to look at the timesheets and assume Mercedes has overcome the reliability issues it suffered on the opening day of testing and business as usual has resumed at the front of the grid. Yet the world champions still appear to be struggling and Valtteri Bottas' gap of 0.1s to AlphaTauri's Pierre Gasly, while using the C5 same tyre compound, is not very convincing.
The usual preseason caveats need to be rolled out at this stage -- not least that we do not know how much fuel the cars were carrying when they set their fastest laps. An F1 car's tank can hold up to 110kg of fuel and every 10kg added costs roughly 0.33s of lap time around the Bahrain International Circuit.
So, if Bottas was running with over half a tank and Gasly was on 20kg, a quick application of the math would result in a more familiar gap between Mercedes and AlphaTauri. The truth, however, is that we don't know.
Instead we have to look to different performance indicators, including how comfortable the car looks on track. It was clear yesterday that the Mercedes drivers were struggling with the balance of the car and that was backed up by Lewis Hamilton's spin on Saturday morning.
Changes to the aero regulations over the winter have been focused on stripping around 10% of downforce from the cars, but have been specifically targeted the rear. Combined with a new tyre construction and windy conditions over the opening two days of the test, it seems Mercedes has yet to find a balance to suit its drivers.
"It's very gusty, as I found out into Turn 13 [when I spun]," Hamilton said. "The rear [of the car] doesn't feel particularly great with this new regulation change but we're trying to find the sweet spot."
Meanwhile, Mercedes' main rival Red Bull has exuded confidence throughout the two days of testing so far. Perez's fastest time was only good enough eighth in the standings, but was set on the second hardest tyre compound (the C2) and in hotter conditions than the fastest lap times when the track was slower.
Performance differences between tyre compounds vary from circuit to circuit, but going a single step softer can usually find at least 0.5s of lap time. Again, applying some very rough math to Perez's lap, which was 1.4s off Bottas on tyres three steps softer, and a different picture emerges.
Red Bull attempted a clear race simulation in the afternoon but it appeared to be brought to an end by a technical issue in the third and final stint. Nevertheless, the fact Red Bull is advanced enough in its testing programme to work through a race simulation is a sign of confidence, and the average lap times -- even on high fuel and C2 tyres -- compared favorably with other teams on long runs throughout the day.
There was a dramatic moment towards the end of the session when Perez's engine cover blew off the car, exposing the tightly packaged Honda power unit. But the incident looked more dramatic that it was and new bodywork was soon fitted to allow Perez to resume.
Another team exuding confidence at this stage of testing is McLaren. Lando Norris' fastest lap, which was 0.3s off Bottas but set on the C4 compound, was the fastest once you factor in tyre choice. Despite changing engine manufacturer from Renault to Mercedes over the winter, McLaren has looked well prepared and an innovation within the new regulations regarding the car's diffuser has already turned heads.
Alpine has also had a solid test, although it opted against a headline time with Fernando Alonso on Saturday evening when the track was at its fastest. Instead Alonso was working on 12-lap runs with heavy fuel, and although the pace wasn't as quick as other teams on long runs, he was able to fire in lap times with metronomic consistency.
"You can see, apart from being a quick driver, he's a great professional," Alpine executive director Marcin Budkowski said. "He's been in the sport for many years in F1 and other categories.
"His feedback is extremely professional, is extremely complete in the information he passes to the engineer. It's great to work with him from this point of view and it's going to be useful to develop the car."
Ferrari has yet to display a significant step forward on its disappointing 2020 season during the first two days of testing, but it's still too early to write the team off. Charles Leclerc's single-lap pace on C5 tyres was underwhelming, although his first sector pace hinted that the team had regained some of the straight-line speed it was lacking throughout last season. It was a similar story over long runs, but without like-for-like race simulations (which we are hoping will take place on Sunday) it's hard to draw a conclusion about the cars in red.
In testing last year, Racing Point's impressive step in performance was one of the main talking points, but arriving in Bahrain as the rebranded Aston Martin team it has not generated the same level of attention. That's not to say the car isn't quick, Lance Stroll was third fastest by the end of Saturday, but a gearbox issue for Sebastian Vettel in the morning meant the team was making up for lost time in the afternoon with stint lengths were kept under 10 laps for the entire afternoon.
The final day of testing on Sunday should be the most revealing of the three. The field seems genuinely close at the moment and Mercedes has not yet shown signs of the superiority we have become used to in recent years, but at this stage it's still too early to write anyone off.