FIA's new F1 flexi-wing regulations, explained

29/05/2025 15:15

New technical rules are in effect starting at the Spanish Grand Prix. Here is what you need to know

This weekend's Spanish Grand Prix marks the third and final race of Formula 1's latest triple-header, which brought the grid from Imola to Monaco, and finally to Barcelona. But as the weekend begins there is one singular focus up and down the paddock.

Wings.

Front wings to be exact, as the sport's governing body implements a new Technical Directive that introduces "a further tightening of the load tests applied to the wings of F1 cars in a bid to address concerns around flexibility and the performance benefits teams might gain through the use of wings that flex under load."

Here's what's happening this week at the Spanish Grand Prix, why it's happening now, and what we can expect to see starting in Barcelona.

What happened last season?

Wings, particularly rear wings, were a major talking point during the last half of the 2024 F1 season.

The major focus was on McLaren and their MCL38, the car that helped power the Woking-based operation to their first Constructors' Championship since 1998. Video footage from the Azerbaijan Grand Prix showed that the rear wing on the MCL38 was flexing under aerodynamic load, possibly more than allowed under the regulations. Some took to calling that a "mini DRS," as it would create a gap in the rear wing that reduced drag and helped straight-line speed, but that gap would reduce when the car slowed in corners, helping create downforce in those sections of the track.

While the team reported that the rear wing complied with the regulations and passed all FIA load tests, they "proactively offered to make some minor adjustments to the wing following our conversations with the FIA" ahead of the next race, the Singapore Grand Prix. "We would also expect the FIA to have similar conversations with other teams in relation to the compliance of their rear wings."

How could a flexi-wing help an F1 team?

In F1, aerodynamics is half the battle.

If not more.

In an ideal world the perfect F1 car would have almost no drag — allowing for incredible straight-line speed — coupled with high downforce, allowing for improved cornering through the turns.

Those two characteristics are not easily compatible, thanks to the laws of physics.

However, flexible wings that create gaps under aerodynamic load would help reduce drag, thereby improving straight-line speed. But when that aerodynamic load lessened, they would revert to their standard shape, which would increase downforce and improve cornering. While not creating the "perfect" F1 car as described above, every little bit — and every tenth of a second — counts.

For more on how a flexi-wing can help an F1 car improve performance, this video from F1TV technical expert Sam Collins is worth a watch.

What changes did the FIA make ahead of this season?

Ahead of the 2025 season, the FIA introduced new regulations aimed at flexi-wings. According to Nikolas Tombazis, the FIA's single-seater Director, these new regulations were needed given the concerns that were raised by teams during the 2024 championship battle. "When championship battles become intense, teams tend to focus on each other's cars a lot, and naturally they raise concerns and over the latter half of the season we came to the conclusion that we needed to toughen a bit more the tests for 2025," said Tombazis.

"The 2025 regulations were designed to counteract the so-called 'mini-drs effect' that became quite a talking point in the autumn of last year," added Tombazis. "That test was applied from the start of the season, but it soon became apparent it was insufficient."

Initially, the FIA focused on rear wings, and mandated in the 2025 regulations that "if 75 kilograms of vertical load were to be applied on either extremity of the rear wing mainplane, the distance between the mainplane and the flap (also known as 'slot gap') should not vary by more than 2 millimeters."

F1's governing body began the year with this stricter testing requirement and installed cameras on the rear wings of the cars at the season-opening Australian Grand Prix. After reviewing the footage the requirements were tweaked again in a two-stage process: At the Chinese Grand Prix, the tolerance was reduced to 0.75 mm, and, at the following race, the Japanese. Grand Prix, the tolerance was reduced again, to 0.5 mm.

This week, however, the focus shifts to the front wings.

What are the new requirements for front wings?

Front Wing Bodywork Flexibility and Front Wing Flap Flexibility are governed by Articles 3.15.4 and 3.15.5 of the 2025 Technical Regulations, respectively.

Previously, Article 3.15.4 read that when "100 kilograms of load is applied symmetrically to both sides of the car the vertical deflection must be no more than 15 mm and when the load is applied to only one side of the car the vertical deflection must be no more than 20 mm."

Starting this week, however, those gaps drop to just 10 mm under symmetrical load, and 15 mm under asymmetrical load.

As for Front Wing Flap Flexibility, the previous version of Article 3.15.5 read that "any part of the trailing edge of any front wing flap may deflect no more than 5 mm, when measured along the loading axis, when a 6 kg point load is applied normal to the flap."

Starting this week, that gap drops to just 3 mm.

These might seem like minor changes, but in a sport where every thousandth of a second matters, they can add up to a pretty big change.

Why is this happening now?

Given all the attention paid to wings over the past few months, and the rule changes already made for rear wings, it is fair to wonder why the FIA waited until the ninth race of the season to address front wings.

As Tombazis explained, it came down to timing, and cost.

Development is a constant process in F1, and as this discussion unfolded during the 2024 season teams were already well into developing their 2025 challengers. Even though the FIA knew that changes would need to be made to the regulations regarding front wings, the cost might be too high for teams given how late in the 2024 season it was.

"Over a sequence of races at and following the Belgian Grand Prix we installed cameras on the front wings of all cars and again we concluded that the tests would need to be toughened," said Tombazis. "That conclusion was arrived at quite late in the year, however, and we felt that if we had introduced extra tests at the start of this season, it would have been tough on teams and may have led to existing front wings being scrapped, and extra expense.

"Therefore, we felt that deferred introduction was more sensible."

What are the teams expecting?

Depending on who you talk to, the new regulations could be a nothing burger, or a "gamechanger."

"Seven days ago we were in Imola at a higher-speed circuit and the car performed very well. We're now heading back to some higher-speed circuits and, of course, essentially a regulation change," said Red Bull Team Principal Christian Horner after the Monaco Grand Prix.

"Now maybe that will have zero impact on the running order, but it's a change and it will affect all the teams maybe neutrally but there will be an impact from it," added Horner. "[I]t's a significant change and so of course there will be some effect. Now, of course, the teams have anticipated that so it may well be neutral or maybe it will have some affect on [tire] degradation. It doesn't make life easier."

"I think what we have seen is that Ferrari was probably most conservative on flexi wings. What it's going to do on the pecking order is something we need to look at. I'm not sure it will, but another angle of curiosity and I don't know how it's going to go," described Mercedes boss Toto Wolff.

"We've been talking around it for a long time," said Sauber Team Principal Jonathan Wheatley — who was Sporting Director at Red Bull until last season — at the Monaco Grand Prix. "Some teams have been gaining a really big advantage from it."

McLaren Team Principal Andrea Stella, however, dismissed the concerns.

"It's good news when our rivals get their focus - rather than on themselves - onto some of the aspects that allegedly are present in our car, and that effectively are not even present," said Stella in Imola.

"Certainly, even if they were - let's say, flexi-wings like a front wing deflection, like everyone else - it has nothing to do with the reason why McLaren is very competitive.

"I hope that in the future there will be more of these kinds of sagas because it means that our rivals keep focusing on the wrong things, and this is, for us, just good news. It's just helping our quest."

However, at least one of Stella's counterparts believes this will be a "gamechanger" in Barcelona and beyond.

"I think Barcelona is on the calendar of everybody in the paddock with the new regulation for the front wing," said Ferrari boss Frederic Vasseur.

"At least we are working on it for ages now and this can be a gamechanger for everybody because we don't know the impact on every single team of the new regulation. We'll stick to this [in Barcelona], be focused on this, to have the better explanation of the new front wing."

Starting tomorrow, the teams will be on the track for the first of three practice sessions ahead of the Spanish Grand Prix.

That will give us our first indication of whether this new change will be a nothing burger or a gamechanger.