F1 2021: How Red Bull have gained on Mercedes to ignite Lewis Hamilton, Max Verstappen battle
Explaining how a 'rake angle' coupled with subtle rules tweaks have shaken up Formula 1's competitive hierarchy as Red Bull get set for title battle with Mercedes; Watch second race of the season - the Emilia-Romagna GP - live on Sky Sports F1 this weekend
By Matt Morlidge
Last Updated: 13/04/21 9:31am
And just like that, the 2021 F1 title battle was on.
For seven years, Red Bull have tried but failed to produce a Mercedes-contending car at the start of a season - often so far off the pace that their championship hopes were over before they were ever really alive.
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But at 2021's opening Bahrain GP, Red Bull well and truly justified the pre-season hype and - while denied a victory by Lewis Hamilton's brilliance - proved their championship credentials to truly ignite the new campaign.
And all this after few notable changes to the cars from last year, when Mercedes were at their dominant best.
That begs the question: How exactly have Red Bull done it?
Let's start from the top. What were the 2021 changes and why were they made?
In a sport that prides itself on car innovation and constant gains, it's rare to see an off-season quite like 2021's.
Due to the financial implications of the Covid-19 pandemic - with the major car and rules overhaul pushed back from 2021 to 2022 - it was decided that there would be few big changes for the last season of the current regulation era in a bid to cut costs.
The alterations were rather niche. And, implemented on safety grounds as F1 looked to reduce stress on new tyres, hardly sounded pivotal.
There were changes to the rear brake winglets, to fences underneath the diffuser, and to the floor - more specifically that venetian blind-like slots were removed, as was a thin slice of the rear part of the floor.
Doesn't sound like much, right?
However, as Mercedes' technical chief James Allison explained to Sky Sports F1's Ted Kravitz, those subtle differences were enough to give F1 teams a "scream moment".
"We've got an adventurous set of rule changes," he said in pre-season. "They may not look adventurous but for anyone that's on the aerodynamics side of car development, they're enough to make you wake up in a cold sweat."
What makes the changes so impactful?
The removal of the rear bit of the floor - with an angling-inwards diagonal slice, compared to a wedge of cheese by Ted at pre-season testing, now apparent - is seen as hugely influential on downforce, and therefore lap time.
"The bit around the rear wheel is insanely sensitive," stated Allison. "That's where a massive amount of the lap time comes from.
"When you are forced to strip away material from here, you haemorrhage lap time off the car."
And that floor change could also be a pecking-order game-changer...
Why has that helped Red Bull get closer to Mercedes?
Put simply, it is believed - now with evidence of on-track running - that the loss of floor downforce has been less of a disadvantage for Red Bull's car design, which has already been aided by a new and improved Honda engine for 2021, than it has Mercedes'.
How are they different, you may wonder. Well, Red Bull have long had a high-rake philosophy, meaning the rear of the car is higher than the front, while Mercedes' dominant hybrid-era cars have all been low-rake, making their car more level from the back to the front.
The higher rake and 'nose down' angle is typically viewed as more aggressive, increasing downforce under the car, while the lower rake angle has a longer floor that usually makes the car more stable. Those two designs have split the field in recent years and in general, there hasn't been too big an advantage from one to the other.
In 2021, however, much of the paddock believes that has changed.
Higher-rake cars such as the Red Bull and the AlphaTauri have impressed - the former having the consensus fastest car on the grid and the latter shining in fifth in Bahrain qualifying - while the only lower-rake cars on the grid in Mercedes and the Aston Martin appear to have taken a relative step back.
"Even if it looks like a carry-forward car there was still… I think we've probably suffered more with the change of regulations than the cars with the higher rake," said Mercedes boss Toto Wolff.
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With the world champions seemingly struggling to recoup as much downforce as high-rake Red Bull have managed, chief trackside engineer Andrew Shovlin added: "Did this set of regulations drag back low-rake cars more than high-rake cars? It may well be the case.
"I know that Red Bull won the last race [of 2020] but generally we were ahead at the end of the year and that's not the case now.
"So either we took a bigger hit with the rules or they've had faster, better rates of development since they applied the regulation changes."
So, higher rake = faster car?
Of course, as Shovlin mentioned, it could just be that Red Bull have done a better job over the winter. Max Verstappen, after equalling his pole position tally for 2020 on 2021's opening weekend, certainly thought as much.
"It's (been) our philosophy now for a long time; I don't think you can point it out on that," said Verstappen about Red Bull's high-rake car. "There have been a few factors.
"We knew our weaknesses from last year that (were) not only to do with rake. I think on the engine side, Honda has worked really hard to improve their engine in general, and I think they've done a great job."
However, Sky F1 expert Mark Hughes pointed out in his column for The Race that it's certainly coincidental that Mercedes, Aston Martin and Haas (who are openly not focusing on improving their car for 2021), were the only three teams who appear to have lost speed when comparing the gap to Bahrain pole last year and this year.
"It's strongly suggestive that the rake philosophy is the driving factor in the changed competitive hierarchy," wrote Hughes.
Otmar Szafnauer, meanwhile, insisted Aston Martin and Mercedes had come in for a "rude awakening".
"The rule changes over the winter obviously had a massive impact on the low rake cars and none at all on the high-rake cars," the Aston Martin team boss told Sky F1.
"We took a huge step backwards due to the regulation change. The others haven't."
Can't the other teams just switch design?
Not a chance, according to Mercedes.
"We wouldn't be able to replicate the concept that Red Bull and some of the other teams have been racing," said Wolff. "It's physically not possible. We couldn't run our suspensions and settings in the way that Red Bull does and so we need to do the best out of it and tune the car to what we have available."
Shovlin stressed: "What we certainly can't do is suddenly say we're going to lift the rear of our car 30mm and work with that, because that would write off the season."
Were the new rules intended to 'peg Mercedes back'?
Hamilton was adamant after being beaten to pole by 0.4s in Bahrain.
"I mean, it's no secret that the changes… of course they've been done to peg us back," said the seven-time world champion, who compared the new rules to the qualifying mode changes from last year.
Szafnauer, whose Racing Point were one of the standout teams of 2020 and even won a race, also isn't happy - claiming it was "pointed out last year by the low-rake runners that this would have a bigger effect than on the high-rake runners. And we were correct."
But others have insisted that nobody really knew who the regulations would favour - such as Mercedes' Allison, who was asked, before cars hit the track at pre-season testing, if they might give the high-rake cars an advantage.
"That is the million dollar question. Absolutely no one knows," he said.
"Certainly every team will be sitting there in a fog of paranoia thinking this is definitely worse than us, while simultaneously hoping it's better for us than it was for anyone else."
F1's governing body the FIA, meanwhile, have made it clear that the rules changes were introduced on safety grounds - and not to shake up the pecking order - after races such as the British GP last year when there were several tyre blow-ups, including for both Mercedes cars.
The new rules may therefore be one of F1's happiest of coincidences.
Closer racing at the front is now predicted throughout 2021 - which continues with this weekend's Emilia-Romagna GP live on Sky Sports F1.