“Mini DRS” Flexi Wing Controversy & the FIA’s Technical Directive for the Chinese Grand Prix
- Nicole Nolte
- Mar 18
- 5 min read
The 2025 Formula 1 season has barely begun, and we’re already seeing some ✨️spicy✨️ technical drama unfold 🤭
The FIA is tightening its grip on flexible rear wings, a looooong-debated area of aerodynamics that teams have been very creative with over the years 😗✌️
👀 Now, with a new technical directive in place starting at the Chinese Grand Prix, the FIA is enforcing stricter rear wing deflection tests, making it MUCH harder for teams to exploit flexi-wings for straight-line speed.
So, what does this mean, how does it work, and which teams might be scrambling to make last-minute adjustments?
What’s the Deal with Rear Wing Flexibility?
Formula 1 teams are CONSTANTLY pushing the limits of the rules to gain an edge.
One of the areas they’ve been playing with is rear wing flexibility – a nifty lil design trick that allows the wing to move ever-so-slightly under aerodynamic load.
Why does this matter?
Well, an F1 rear wing has two conflicting jobs:
1. High downforce for corners: The wing needs to generate grip by pushing the car down.
2. Low drag for straights: Too much downforce means too much resistance (drag), slowing the car down on high-speed sections.
If a team can design a rear wing that flexes juuuust enough to be stiff under FIA’s static load tests but still bend at high speeds, then they can effectively reduce drag on straights while still getting full downforce in corners.
That’s basically a “mini-DRS” effect without actually using DRS. And as you might guess, the FIA isn’t too happy about it 😅
What Are the FIA’s New Rules?
At the Chinese Grand Prix, the FIA is rolling out a new ✨️technical directive✨️ (TD) to further restrict rear wing flexibility.
⏮️ Before
The old rule allowed a maximum 2mm of movement when 75kg of force was applied to the rear wing.
⏯️ Now
The FIA has squashed that tolerance to just 0.5mm, meaning teams have almost NO room for movement under load.
⏭️ Temporary Exception for China
Due to the short notice of the rule change, the FIA will allow a 0.25mm discrepancy for this weekend only before fully enforcing the 0.5mm rule at the Japanese Grand Prix (6 April 2025)
This means teams that were previously getting away with slight flexing will now have to make urgent modifications to comply -- or risk penalties.
Why Is the FIA Cracking Down Now?
The FIA has been monitoring rear wing behavior veeeery closely in 2024 and early 2025, and here’s what they’ve come up with…
Slow-motion replays and onboard footage from practice and the AusGP showed that some teams had wings flexing more than expected.
The FIA has been running increased checks (garage inspections + load tests) during scrutineering and has noticed some "borderline" designs.
Some teams (👀 cough cough Mercedes, Aston Martin) have reportedly raised concerns with the FIA, arguing that some competitors are gaining an unfair advantage.
This isn’t the first time F1 has had a flexi-wing saga, but the new tests aim to end the loophole once and for all.
... At least that’s what they think 😶
So Why Is This a Problem?
On paper, it sounds like just another clever engineering trick, right? 🤷♀️
So why is the FIA suddenly cracking down on it? Are they being dramatic?
... Well, not exactly.
It’s against the rules
While teams are technically passing the FIA’s tests, they are still exploiting a loophole to gain an advantage.
The rules were designed to make aerodynamics predictable and fair across the grid.
Unfair performance gaps
If some teams have a rear wing that gives them extra top speed without DRS, it puts those without it at a serious disadvantage - especially on tracks with long straights, like Shanghai (this weekend!) and Monza.
Safety concerns
A wing that flexes too much at high speeds could be at risk of failing, and at 300 km/h+, a structural failure is... not something you want to see 🫣
Sooo, long story short?
The FIA has seen enough, and they’re putting their foot down ✊️
Which Teams Could Be Affected?
The FIA hasn’t officially named & shamed any teams in their directive, but paddock rumours are pointing fingers at three main suspects rn...
Suspect #1 - Ferrari
Ferrari reportedly made some late-winter mods to their rear wing to improve straight-line speed.
BUT their design might now be too flexible under the new regulations, meaning they’ll have to tweak it ASAP.
Ferrari has had past flexi-wing issues, so they miiiiight be treading carefully this time.
Suspect #2 - Red Bull
Red Bull is NOTORIOUS for pushing aerodynamic innovation (cough cough DAS, blown diffusers, floor tricks, etc.), so they’re pretty much always on the FIA’s radar (which, fair enough)
Their RB21 rear wing has been seen moving slightly in onboard footage, particularly at high speeds (suspicious 👀)
Christian Horner insists everything is legal (ofc he would), but we’ll see if they make sudden changes in China... 🧐
Suspect #3 - McLaren
McLaren’s 2024 rear wing design was already being watched last year for how much it moved under load, and they had to tweak it slightly in late 2024 to pass FIA tests, but with the new 0.5mm rule, they may need even more adjustments.
Their straight-line speed in Melbourne looked suspiciously good—was that thanks to aero trickery? 👀
🤭 Guess we'll find out this weekend...
It’s also possible that other teams like Aston Martin or Mercedes have minor flexing issues, but they haven’t been under as much scrutiny - yet (DUN DUN DUNNNNNN)
(This is the FIA we're talking about, no one is safe lol 😹)
How Will This Impact Teams in China?
Rushed Upgrades
Any team that was exploiting this will NEED to adjust their rear wing immediately to pass the new test. If they don’t, they could face penalties or even disqualification - which isn't cute 😗✌️
Possible Performance Drops
If a team WAS relying on a flexi-wing for straight-line speed gains, they might lose some top speed on the long Shanghai straight.
New Aero Trade-Offs
Teams might have to increase their DRS reliance or tweak front-wing setups to balance out any lost performance.
So... Will This Rule Change Shake Up the Grid?
Any time the FIA clamps down on aero loopholes, it has a ripple effect.
So... if a top team like Red Bull, Ferrari, or McLaren was depending on a flexible rear wing, we might see them lose some straight-line speed in China.
This could...
Make overtaking harder for them (especially on Shanghai’s long straight).
Give Mercedes or Aston Martin (even Williams tbh) a chance to close the gap.
Force teams to rethink their aero setups going forward.
If McLaren or Red Bull suddenly look slower in Shanghai, you’ll know why 😅
What do you think? Will this rule shake up the pecking order? 🤔 Let’s see what happens when the cars hit the track (I CAN'T WAIT!)
TL;DR: What’s Changing?
The FIA is tightening rear wing flex rules starting at the Chinese Grand Prix.
Old 2mm movement limit is now just 0.5mm (0.25mm leeway for China).
Red Bull, McLaren, and Ferrari might be forced to adjust their designs.
Could impact straight-line speed & overtaking ability for affected teams.
We’ll see in China who really had a flexi-wing advantage.
And it's race weekend!