Formula 1 testing has finished with Mercedes’ George Russell quickest on the final day and Carlos Sainz fastest for Williams overall.
But that’s not the real picture. Here’s what we learned from three days in Bahrain where we’ve spent hours trackside, analysed hundreds of laps, and heard from all the teams and drivers.
Red Bull has problems
There are a few reasons why Red Bull seems on the back foot after testing, despite a decent looking late Max Verstappen flier to go second-fastest on the last day.
It was already playing catch-up a little bit after a water leak slightly limited Liam Lawson’s full day in the car on Thursday.
Early on Friday there were whispers that a 2024 trait of understeer leading to exit oversteer was still apparent. But Red Bull was nowhere near ready to be able to put together a race run as Verstappen tried a variety of set-ups, wing and floor combinations, losing a lot of track time in the process.
In a two-hour trip trackside at the end of the day, we noticed three separate runs in which Verstappen appeared with flo-vis on a sidepod - twice on the right-hand side, once on the left, and in different parts of the sidepod each time.
It suggested that right up until almost the final moments of testing, Red Bull was still running tests in search of something. And technical director Pierre Wache admitted "it was not as smooth a test as we expected”.
Eventually, near the end of the day, Verstappen found a combination which worked. But it doesn’t look easy and Wache even hinted that the steps being made were not as big as Red Bull expected.
Who’s really on top
Long run analysis suggests the McLaren MCL39’s small but significant advantage remained, this time with Oscar Piastri driving instead of Lando Norris. Piastri was also set to go quickest on the final day before a moment at the final turn.
Some in the paddock are very worried about the speed of the McLaren, which has also attracted attention for the movement of its rear wing - but more on that later.
If there is a potential weakness, it’s the rear instability that was well documented on day two, but McLaren’s clearly the early favourite.
While neither Mercedes nor Ferrari turned heads the way McLaren did, they look closely matched almost all week on short and long runs.
The Mercedes looks the easier car to drive, although with a tendency to lock up, but the Ferrari may have a bit more pace in hand.
Russell, fastest on day three, said it had been a “seamless” test while trackside engineering director Andrew Shovlin said Mercedes could be pleased with how it has gone.
"The team has worked hard over the winter to improve on the weaknesses of the W15 and, from the initial signs, we seem to have made good steps in those areas with our 2025 challenger,” said Shovlin.
Ferrari data was compromised on the final data when Lewis Hamilton couldn’t perform a race simulation as planned in the final hours. His day ended early “as a precaution, having spotted an anomaly on the telemetry”, Ferrari said.
The worst car
The Sauber was consistently the least impressive car from trackside through the test, and its pace was nothing to write home about either, both on short runs and long runs.
Even by the standards of the current generation of ground effect Formula 1 cars, it appeared uncomfortably stiff and the failure to make it a little more compliant suggests a narrow set-up window. That's consistent with the fact the team struggled particularly badly on the first morning with its initial set-up.
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Nico Hulkenberg used all of his experience to get some kind of consistency out of the car, but it always looked a little unstable and far from confidence inspiring. He dodged questions about the car being too stiff after the session, although did eventually concede after that evaluation was put to him that "maybe I told them [the engineers' it's stiff too]".
While the car doesn't look disastrously off the pace, it's at the back and were a qualifying session to be held in Bahrain right now the Saubers would surely be eliminated in Q1. That means there's a lot of work to do.
The most improved car
The Williams isn’t really the fastest car after testing, even though Sainz’s day two time puts it at the head of the times.
But it could be the most improved and caught the eye on all three days. It’s a car that fundamentally is working well, even if its peak came when it was particularly light or with a higher engine mode or, as with Alex Albon going third-fastest on day three, using a softer compound tyre than most.
Team figures were keen to play down just how strong it may be, and there is no indication it has jumped to the front of the midfield and bridged the gap to the top four.
In reality, Williams is a bit further back from that – but it left a strong impression in Bahrain and will be expected to fight Alpine for a Q3 berth and points in Australia.
Alpine was positive about its own performance this week, and justifiably so. The car looks decent on track and the drivers have fed back their relative satisfaction.
It was also a debut this week for a revised trackside leadership. Sporting director Julian Rouse is now focusing solely on the Alpine Academy that he was also previously director of alongside his senior F1 team role, and in his place is a new structure.
Dave Greenwood, once Kimi Raikkonen's race engineer, has joined as racing director - which is a new role for this era of Alpine at least - while ex-Williams man Richard Lockwood is strategy and sporting director.
Greenwood worked with Alpine team boss Oliver Oakes at Hitech and Oakes says the new structure is to give him the support he feels he needs on race weekends after taking charge last August.
Aston Martin hasn't done enough
When Adrian Newey starts at his new team Aston Martin next week, he might kick things off by digesting some worrying data from this test.
Aston Martin’s got a lot to prove this year and has supposedly changed a lot on its car in a bid to solve the problems that caused it to slump across last season.
Though it finished fifth in the championship last year, a perfectly respectable result, its performance trajectory was poor for the second year running. By the end it had only the eighth or ninth fastest car - and sometimes it was outright slowest.
It’s very concerning, then, that Fernando Alonso indicated Aston Martin is where it was in Abu Dhabi at the end of last season. As a reminder, that was behind several midfield teams and struggling to score points.
Aston Martin wanted to make this car more benign and give the drivers confidence, and while it’s looked like that’s been achieved to a degree, the car lacks pace.
“We have also discovered areas that could be better and need more focus,” admitted Andy Cowell, Aston Martin team principal.
Mini-DRS war revived
F1 already looks to be heading for its first tech controversy of the year, as mini-DRS chatter returned to the paddock on the final day of testing.
As teams began to dig a bit deeper into what their rivals are up to with their 2025 designs, some eyebrows have been raised about the behaviour of rear wings.
Onboard footage from rearwards facing cameras have highlighted some interesting behaviours over the week – with some wings like the Mercedes’ appearing to notably bend back on the straights before popping back into an upright position when the car slows for corners.
But, as Red Bull technical director Wache pointed out on Friday, other rear wing flexi tricks have been spotted too – with suspicions that some teams could be trying to exploit the mini-DRS benefit that McLaren put to good use last year.
“It is still going on,” explained Wache. “I think Ferrari and McLaren are doing the mini-DRS stuff still.”
Wache’s reference relates to the trick of flexing the rear wing main plane to help open up the slot gap – which will reduce drag and provide a boost to straightline speed.
McLaren pioneered mini-DRS last year, with the concept helping Piastri win the Azerbaijan Grand Prix. However, following discussions with the FIA - which had been on the receiving end of complaints from McLaren’s rivals - the team agreed to subsequently tweak the design.
For 2025, the FIA has implemented tough rules to try to eradicate mini DRS games – but the eyes of McLaren’s rivals will now be on whether it has found another way to extract similar gains with its new car.
Stitch-up for the 'real' rookies
There’s a big crop of rookies on the grid this season but maybe only two ‘real’ ones as they’ve been inadvertently stitched up a little by F1’s rules.
Limited testing is often criticised. Sainz actually revealed a surprisingly impassioned complaint about that this week saying he can’t imagine what it’s like to have to make your F1 debut when pre-season involves just three days shared between two drivers.
Ollie Bearman’s at least raced in three grands prix already and Jack Doohan made his debut in Abu Dhabi. Both have also done extensive testing in older cars in the past - and Kimi Antonelli’s racked up thousands of miles with Mercedes’ private testing programme too.
But Gabriel Bortoleto and Isack Hadjar are in a different position and have huge learning curves, much bigger than the grid’s other three rookies.
They hadn’t done much testing at all last year. Then new limitations on testing older cars kicked in for 2025.
It meant Sauber and Racing Bulls opted to only give their rookies one day in 2023 cars before testing - saving some mileage for later on just in case.
Both sounded quite happy with their progress in the circumstances but it could be a baptism of fire given Bortoleto’s probably driving the slowest car and Hadjar looked quick but erratic.
Weird problems
Haas mainly concentrated on long-run form rather than performance running at this test but there is one specific thing the team needs to get sorted before Melbourne.
A strange bodywork problem has now struck it twice. At the team’s Silverstone shakedown, Esteban Ocon was spotted returning to the pits with some missing sidepod bodywork – while Bearman had the same dramas on Friday in Bahrain as bits again flew off.
Team boss Ayao Komatsu didn’t reveal what the cause of the issue was, only saying that a modification had been made from last year that was clearly “too aggressive”.
But he says it will not be a problem to sort. Which implies Haas may have tried to save weight around the bodywork or the fasteners and just needs to beef this up for the season opener.
Speaking of weird problems: Bearman inadvertently caused one of three odd red flags at this test when his car flicked up a stone that smashed a window from the trackside gantry.
That caused the Friday morning session to be halted while shattered glass that fell on to the circuit was cleaned up.
Another bizarre stoppage came just seven minutes into the afternoon session when one of the small buses transporting personnel around the circuit access roads accidentally ended up in the run-off area between Turns 9 and 10 after taking a wrong turn.
