In the immediate aftermath of Sunday’s Australian Grand Prix, the FIA has announced to teams that it will crack down on rear wing flex.

A technical directive was issued to teams yesterday morning in which the tolerance for allowed flexibility was significantly reduced.

In Melbourne, a static load test saw 75 kilograms placed at either end of the rear wing mainplane, with the gap to the flap (the ‘slot gap’) then measured.

In Albert Park, the rules allowed a variance of 2mm.

From China, that figure has been slashed to just 0.5mm, with a tolerance of 0.25mm owing to the short turnaround.

“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,” an FIA statement announced.

“In addition, the FIA requested to 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.”

FIA tightens rules on F1 flexi-wings

The change comes off the back of the Australian Grand Prix, where all cars complied with the regulations as they were then written.

However, Speedcafe understands some teams were close to the allowable threshold and could, therefore, be at risk under the revised test.

Flexible rear wings hit the headlines last year with McLaren a notable proponent of the practice.

At the Azerbaijan Grand Prix, television footage from Oscar Piastri’s car showed the slot gap on his rear wing opening slightly at high speed despite not having DRS available to him.

The FIA reacted by asking the Woking squad to amend its rules following a reinterpretation of the regulations ahead of the Singapore Grand Prix.

Changes to the load tests on both front and rear wings were already planned.

The new directive hastens that process for the rear wing as the governing body looks to close off the loophole.

Track action at the Chinese Grand Prix begins on Friday, with Free Practice 1 beginning at 14:30 AEDT.