What are flexi-wings and why have they made headlines in 2025?

As soon as wings first appeared in F1, teams began exploiting the performance potential of flexible bodywork.

In 1968, the first year of wings in F1, Ferrari pioneered a rear aerofoil that could be adjusted by the driver using a hydraulic system.

Others followed before such designs were outlawed, but right from the start it was clear there was performance to be gained from varying the angle of attack of wings, and also bodywork in general.

The benefits of having wings that flex at high speed are enormous. If you can make the front or rear wing ‘back off’ - usually with the flexibility creating a rotation that reduces the angle of attack of the aerofoil - at high speed you reduce drag and increase performance on the straights.

Then, when the car slows, the wings return to their normal position and give you the required downforce. Provided this effect is controlled well enough to generate downforce when it is required, the laptime will improve.

The battle between rulemakers and designers is ongoing. That’s despite flexible bodywork being emphatically outlawed by Article 3.2.2 of the technical regulations. This states:

“With the exception of the driver adjustable bodywork, when in the state of deployment, as described in Article 3.10.10 (in addition to minimal parts solely associated with its actuation) and the flexible seals specifically permitted by Articles 3.13 and 3.14.4, all aerodynamic components or bodywork influencing the car’s aerodynamic performance must be rigidly secured and immobile with respect to their frame of reference defined in Article 3.3. Furthermore, these components must produce a uniform, solid, hard, continuous, impervious surface under all circumstances.

“Any device or construction that is designed to bridge the gap between the sprung part of the car and the ground is prohibited under all circumstances.

“With the exception of the parts necessary for the adjustment described in Article 3.10.10, or any incidental movement due to the steering system, any car system, device or procedure which uses driver movement as a means of altering the aerodynamic characteristics of the car is prohibited.

“The Aerodynamic influence of any component of the car not considered to be bodywork must be incidental to its main function. Any design which aims to maximise such an aerodynamic influence is prohibited.”

That said, it’s impossible to have infinitely flexible bodywork - otherwise it would be too heavy, too brittle and prone to cracks.

There must be some give and movement, which is why the general regulation is augmented by a series of load tests.

These define acceptable real-world flexibility. However, advances in high-speed camera technology mean F1 is close to being able to monitor flexing at all times on track, so enforcement using those techniques might not be far away.

The flexibility can be refined based on the structural design in terms of the carbon fibre layup and weave used in making the parts. The key is that they pass the load tests conducted by the FIA on site at grands prix.

Unfortunately, these cannot recreate the loads wings and bodywork will be subject to at high-speed on track. That’s because the apparatus used must be portable and able to be safely operated when set up in a garage at the track.

Effectively, it’s these tests that govern what flexibility is permitted, and this is what the recent F1 technical directive that came into effect for the 2025 Spanish Grand Prix changed by reducing the amount of flexibility permitted.

This means F1 teams design the cars to exploit the permitted flexibility as far as possible. But the focus isn’t solely on flexing entire wing assemblies as more localised flexibility with benefits from creating that effect with the likes of wing tips and DRS (drag reduction system) flaps.

The rules constantly chase such tricks, including in 2024 the so-called ‘mini-DRS effect’ that used flexibility to open the slot gap slightly when the DRS was not activated, but there’s no end to this battle.

Under the current regulations, front wing flexibility has become even more critical when it comes to achieving good car balance.

Ground effect racing cars always face a challenge in getting enough downforce towards the front of the car, the problem being that if you load up the front wing you can have problems in the high speed.

Mercedes technical director James Allison explained the problem when his team introduced a flexible front wing during the 2024 season.

“All these cars like being near the ground [to generate downforce],” he said. “The front wings on these cars are very big and they probably like being near the ground most of all, and that tends to make a car get more nervous as it goes faster because proportionately more is moving to the front axle than you might wish. So you're fighting that with these rules.

“And the more you find downforce near the ground, the worse that gets. So everyone, in 2022, when these [ground effect] rules were first published, weren’t as near to the ground as they are now, weren't fighting this inherent behaviour as much then as they are now. And this is just helpful with that.”

What Allison means is that the front wings work in ground effect and will get closer to the ground at high speed.

If you run the amount of front wing required to maximise low-speed downforce, it means that at high-speed it will be producing huge amounts of ground-effect downforce. That is what leads to the instability with too much grip at the front.

If the front wing backs off at such speeds the ground effect is less powerful and a good balance is produced. So, if you want a car that works well across a wide range of corner speeds in F1 today, you need a flexible front wing.

Regardless of the wider regulations, flexibility in bodywork will always be harnessed by teams for performance advantage and the battle with the rulemakers therefore goes on in perpetuity.