Explained: Why the FIA has introduced even more flexi-wing directives

Another day, another Technical Directive – what is the focus of the latest push from the FIA to clamp down on flexing wings?

Ahead of this weekend’s Chinese Grand Prix, another technical directive has been circulated to all teams to reduce the permitted levels of flexibility of the rear wings in what has been a continuation of a ‘mini-DRS’ saga.

F1 flexi-wings: Why are there more FIA technical directives?

Additional reporting by Matt Somerfield

The latest technical directive being introduced at this weekend’s Chinese Grand Prix, TD055A, is the introduction of stricter static load test limits on the rear wings of the Formula 1 grid.

Every team is subject to these tests at every Grand Prix weekend, pulling and prodding the rear wings through a series of prescribed loadings to ensure the level of flexibility is within the permitted range.

During last season, it became apparent that the static load tests perhaps weren’t telling the full story, however. With front and rear wing flexibility clearly visible on TV footage flexing visually beyond the prescribed limits, while still passing the static load tests, this begged the question of whether or not the static load tests are up to the standard required to keep ahead of the teams’ ingenuity.

The most egregious example of this last season was after the Azerbaijan Grand Prix when the rear wing of McLaren’s MCL38 could be seen ‘opening’ – in a similar, albeit reduced, fashion to the DRS.

The effect of the opening of the main plane through this flexibility became colloquially known as a ‘mini-DRS’ effect and stood McLaren in good stead as Oscar Piastri held off the attacks of Ferrari’s Charles Leclerc down Baku’s long straights, despite not having DRS to defend against the SF-24.

Following behind-the-scenes protestations from Red Bull and Ferrari, the FIA moved to ensure McLaren made changes to the rear wing design going forward, with the Woking-based squad making “proactive” changes to all of its rear wing range for the rest of the season, while the FIA’s Nikolas Tombazis indicated McLaren may have faced tougher sanctions had they not made the alterations.

The process of evolving how the level of flexibility will be checked began at last year’s Belgian Grand Prix, with the FIA introducing TD034G – this TD instructed select teams to fit high-resolution 4K cameras to their cars in order to allow the governing body to assess what the front wings were doing on track more closely.

While the initial position was to simply use that information to data-gather and prepare for stricter static load tests for F1 2026, with single-seater director Nikolas Tombazis stating in December 2024 that the intent was to leave things as they were for F1 2025, a technical directive was issued to the teams in late January 2025.

TD018, which was first introduced during the 2023 season, was revised and circulated to the teams, confirming more stringent front-wing checks. These tests will be introduced from this year’s Spanish Grand Prix, with the permitted level of flex reducing from 15mm to 10mm.

The delay in the introduction of the new static load tests has caused some consternation, given that it essentially allows those who have evolved their flexi-wing solutions to a greater extent to continue using them for the first eight race weekends – and reduces the reward for those trying to play catch-up, due to the diminishing returns available as a reward for the resources spent.

With an end date in sight for the front-wing flexing controversies, attention has now turned to the rear wings.

F1 flexi-wings: FIA further exercise their authority

Over the winter, the FIA moved to clamp down on the issue by updating the Technical Regulations by addressing rear wing profiles.

“At all points along the span, the rear wing profiles must have a minimum gap of between 9.4mm and 13mm,” reads Article 3.15.17 of the Technical Regulations.

“This will apply when the DRS is not in the state of deployment and will be measured with a spherical gauge.”

The rules pertaining to the DRS have also been tightened up under Article 3.10.10, with an exact definition of deployment offered as meaning DRS usage starts when “the adjustment of the DRS bodywork away from its original geometry has been commanded by direct driver input and controlled using the control electronics, and ending when the DRS bodywork has been returned to that same original geometry, having been disabled by the control electronics.”

Furthermore, while deployed, “At all points along the span, the two sections of the rear wing profiles must have a minimum gap of between 9.4mm and 85mm. This will be measured with a spherical gauge.”

But it was clear a grey area remained after pre-season testing as the FIA took further measures to try to understand what was going on, as a revision to TD034G was made – forcing teams to fit high-resolution cameras to their cars to monitor the level of rear-wing flexibility.

According to Red Bull’s technical director Pierre Waché, McLaren and Ferrari are “doing the mini-DRS stuff still.”

The deformation seen in the limited amount of rear-facing footage that was available during pre-season testing shows a larger gap open between the trailing edge of the main plane and the leading edge of the tip section.

This region of the wing was not covered in the alterations made to the technical regulations over the winter.

FIA introduces new technical directive with immediate effect

Unlike the leeway given to the teams regarding their front wings, allowing them a few months of lead time to revise their designs, the steps taken to counter what has been uncovered over the Australian Grand Prix weekend are immediate.

On Monday, March 17th, 24 hours after the chequered flag in Melbourne, Tombazis circulated the new TD055A to all teams informing them of changes to the permitted levels of flexibility. The teams won’t even have the chance to get home to make the required changes, with the static load tests changing from this weekend’s Chinese Grand Prix.

The compliance checks pertain to Article 3.15.17 of the technical regulations, the area of rear wing mainplane tip flexibility – the permitted level of flexibility under the regulations was 2mm.

For the Chinese Grand Prix, this section of the rear wing will have a permitted level of flexibility of 0.75mm when the usual static load tests are carried out.

The permitted flexibility will be reduced further for the following round, the Japanese Grand Prix, with the limit reduced to 0.5mm of flexibility.

The static load tests themselves – the load application points, means of application, and measurement methodologies, all remain unchanged.

These updated limits will remain in place for the season, with the intention being for the new tweaks to be formally amended into the Technical Regulations through ratification by the World Motor Sport Council by the end of March.

The rapid limit changes are understood to be in response to what the FIA witnessed from monitoring their own high-resolution cameras in Melbourne, allowing for more accurate data analysis than what the world feed allows.

Multiple teams are said to have been showing clear visual excessive flexibility while still passing the static load tests, but these teams remain nameless.

Approached for comment, an FIA spokesperson said, “As has been previously communicated, between the end of the 2024 season and the start of the 2025 season, the FIA exercised the authority it is granted under Article 3.15.1 of the Technical Regulations to introduce either new or more challenging load-deflection tests for the front wing (from Race 9, Spanish Grand Prix), the upper rear wing, and the beam rear wing.

“In addition, the FIA requested the teams to use cameras in Free Practice Sessions to monitor the on-track deformations exhibited by the cars during the Australian Grand Prix.

“Having analysed footage from the rear wing deformations combined to the static deflections measured inside the FIA garage in Melbourne, the FIA has concluded that sufficient grounds exist for a tougher test to be introduced from the forthcoming Chinese Grand Prix on the upper rear wing.

“More specifically, Article 3.15.17, introduced in 2025, states that if 75Kg of vertical load is applied on either extremity of the rear wing mainplane, the distance between the mainplane and the flap (also known as “slot gap”) must not vary by more than 2mm.

“From the forthcoming Grand Prix in Shanghai, this limit will be reduced to 0.5mm. Due to the short notice for Shanghai only a tolerance of 0.25mm will be added to this new limit.

“The Teams were informed of this revised test early Monday 17th of March.

“The FIA wishes to further confirm that during the Melbourne event all cars tested against the requirements of Article 3.15.17 and found to comply, therefore all cars raced in Melbourne were deemed to be legal.”

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