McLaren insists it was not the worst offender in triggering Formula 1's ‘mini-DRS' clampdown, as Alpine became the first team to admit on Friday that it has had to make changes to its rear wing.
As revealed by The Race, the FIA's decision to introduce tougher rear wing flexibility checks for the Chinese Grand Prix was prompted by suspicions that four teams may have been pushing the limits of the rules too much.
While the individual competitors have not been officially named, it is understood that those in the spotlight were McLaren, Ferrari, Alpine and Haas.
Much of the focus for the tech intrigue has surrounded frontrunners McLaren and Ferrari, but both squads have played down their need to make any changes to their designs for the Chinese GP.
Speaking on Friday, McLaren's technical director (engineering) Neil Houldey did not deny that the behaviour of his squad's rear wing has caught the attention of the FIA, but he thinks others were actually exploiting the mini-DRS effect more.
"I think when you look at some of the footage and some of the images from testing, there were certainly teams that were pushing the boundaries on slot gap opening more than us," he said.
Alpine modifications
With Haas already admitting it was likely to need to make set-up changes to its wing to comply with the new restrictions, Alpine has gone further and said that it has had to work on its design this week to make modifications.
The team's racing director Dave Greenwood said: "We've had to do some work back at the factory to make sure we were in the correct place here.
"But I think that's fairly normal in these situations when a rule and an allowance of deflection changes. You need to check that you are going to be able to comply with that as well."
Greenwood would not elaborate on how significant the changes to Alpine's rear wing were, but said staff at its Enstone factory had worked hard to get everything sorted in time.
Asked what modifications were made, Greenwood said: "I'm not going to go into that level of detail, honestly.
"But there's work that needs to go on to make sure it's compliant. That's been done and we are there.
"You can imagine the timescales were very small. It's not like you can do something revolutionary, but there are things we can do to make sure we comply."
McLaren's second wing intrigue
McLaren has been clear that it has not had to make any changes to its wing for the Shanghai weekend, as it has stuck with the same design that it also used in testing.
Its confidence in compliance comes after Lando Norris's car was tested for rear wing flexibility in Australia to check for slot gap variance, and the results showed it was already within the new FIA limits.
Houldey added: "Luckily we were tested in Melbourne, and the numbers that the FIA chose to put in the TD are higher than the deflection that we'd seen.
"So it's had absolutely no impact on us at this event. The performance should be no different for us."
There has been some intrigue, however, about whether an alternative low-downforce rear wing that McLaren has used in testing and tried out in Australia is the one that prompted some mini-DRS questions.
Houldey explained that that specific wing had not undergone the FIA tests, but he was confident it would still fully comply with things.
"I think we'll be OK with that one, but that one hasn't been through the same process as the high downforce one that we're running now," he said.
"The expectation is that, again, we're not going to be losing performance from the TD as we go further into the season."
Asked if McLaren would have been able to make a modified wing in case it did not comply with the new limits, Houldey said: "We would certainly struggle. So it's fortunate that we were in the position that we were and didn't have to make any changes.
"I don't know how other teams have managed it, but maybe there are set-up changes that they've been able to make that don't require new components, or maybe they've had to make something incredibly quickly to get it here and become legal."
Chinese GP car updates
Only a few modest upgrades have been declared by F1 teams for the Shanghai weekend. Mark Hughes runs through them:
McLaren
The pacesetting team has a new winglet atop the rear brake duct to improve airflow around the diffuser.
Racing Bulls
A circuit-specific double beam wing and gurney flap is available for the front wing.
Williams
A larger span version of the beam wing used in Melbourne is available in another circuit-specific move.
Sauber
Having only brought much of its actual 2025 car package for the first race rather than testing, there’s another notable change at Sauber this week too.
It has a modified engine cover and lower ‘coke bottle’ area bodywork as an additional part of the upgrade seen in Melbourne.
