Formula 1 teams will face more stringent rear wing flexibility tests from the FIA at this weekend's Chinese Grand Prix.
The FIA was closely monitoring the on-track deformations exhibited by the cars during the season-opener in Australia.
Extra high-definition cameras were fitted to some cars to help capture footage of the rear wings in action out on track during practice, with reference dot stickers attached to the cars to help the FIA’s monitoring.
Based on analysis of the footage that it captured, alongside static deformations measured inside the FIA garage in Melbourne, the FIA concluded it needed tougher tests on the upper rear wing immediately, as reported by Autoracer.it.
The FIA already introduced tighter restrictions on rear wing flexibility for 2025, with the slot gap (distance between the mainplane and the flap of the rear wing) mandated to not vary by more than 2mm.
That limit will now be reduced to 0.5mm from Shanghai onwards.
Given the short notice of the tighter restrictions - teams were only informed on the Monday after Melbourne - a tolerance of 0.25mm will be added to the limit, theoretically making the actual figure 0.75mm for China-only. It will be 0.5mm thereafter.
The FIA clarified that all teams tested in Melbourne were found to comply with Article 3.15.17 and were deemed legal.
The FIA’s move to tighten up on rear wing flexibility comes against the backdrop of fresh suspicions about aero elasticity tricks this year.
During pre-season testing, Red Bull in particular was unhappy about the behaviour of the rear wings on other cars – as it suspected some wings were flexing too much and manipulation of the slot gap was taking place.
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The rear wing of the Mercedes was captured on rearward facing cameras appearing to flex back on the straights, while slot gap expansion spotted on some cars appeared to mark the return of ‘mini-DRS’ antics.
This latter idea had popped up in the latter stages of last season when McLaren used its ‘mini-DRS’ to help boost the straightline speed of its car – and it helped Oscar Piastri win the Azerbaijan Grand Prix.
Following complaints from competitors, and dialogue with the FIA, McLaren agreed to make modifications to the rear wing to stop the antics.
In a bid to prevent teams exploiting this area in to 2025, changes were made to the technical regulations for this year.
There was also a clear regulation that stated the DRS bodywork position could now only either be in the open or closed state - so cannot be flexed to be in states where it moves around.
However, those tweaks did not appear to have done enough to prevent teams still trying to push the boundaries in this area.
Red Bull technical director Pierre Wache told The Race during pre-season testing that, despite the FIA’s best efforts, some teams still appeared to be exploiting this area.
"It is still going on," he said. "I think Ferrari and McLaren are doing the mini-DRS stuff still."
Other teams had suggested that observation of flow-vis paint on the rear wings of some cars had also hinted at unusual behaviour taking place in how the rear wings were flexing at speed.
Beyond the issue of rear wing flexibility, the FIA is introducing tougher stress tests on front wings from the Spanish GP.
