Speculation in Formula 1 got intense during the summer break in the wake of a change the FIA made to the technical regulations outlawing asymmetrical braking systems.
Off the back of the most recent FIA World Motor Sport Council meeting that ratified a host of revised and future rules, an added clause regarding braking systems set tongues wagging.
The changed Article 11.1.2 of F1's Technical Regulations had some fresh text which is in bold below.
"The brake system must be designed so that within each circuit, the forces applied to the brake pads are the same magnitude and act as opposing pairs on a given brake disc. Any system or mechanism which can produce systematically or intentionally, asymmetric braking torques for a given axle is forbidden."
The nature of the mid-season change to the technical regulations, something which is not very common, fuelled a wave of speculation that the FIA was responding to a device that one or more teams may have been using this season.
There were even wild accusations thrown at Red Bull that its drop of form since the Miami Grand Prix was linked to a potential banning of a system it may have been using - with some even suggesting that Max Verstappen's retirement from the Australian Grand Prix could have been linked to this.
However, the reality of the situation is very different as high-level sources at the FIA have explained that the change was not prompted at all by anything teams were doing at the moment – it was more about future-proofing regulations.
An FIA spokesman told Autosport: "There is no truth that any team was using such a system."
So what was going on?
Ultimately the tweak alters very little when it comes to the legality of asymmetric brake systems. The changes made by the FIA to 11.1.2 of the technical regulations are supplemental to the original text, which only implies that the forces being applied to the brake pads are equal on either side of the calliper.
The new and additional text forbids the braking circuit, either front or rear, to be able to produce asymmetric braking torques.
It therefore prohibits what would more commonly be referred to as a brake steer system, whereby one wheel, usually the inside wheel, is braked with more bias than the outside, in order to help balance and steer the car.
However, according to FIA sources, the wording that was originally in place was already enough to make any asymmetric braking system illegal anyway.
The real motivation in changing the rules instead came from efforts to tidy up the regulations for 2026, and make it clearer in the next rules era what was and was not allowed.
As part of the ongoing discussions to frame the 2026 regulations, a specific clause has been added to the rules to outlaw asymmetric brake systems completely.
And, following a request from teams to ensure that nobody tried to exploit the tiniest of grey areas before then, it was requested that the new clause be added to both the 2024 and 2025 regulations.
McLaren history
Brake steer devices are not a new thing in F1. Famously, McLaren had such a system on their cars in 1997/98, known as a fiddle brake, which employed an additional brake pedal in the cockpit to apply braking force to just one side of the car.
Such a device is, of course, still outlawed, having been prohibited by regulation changes at the time and now covered in 11.1.3.
The rules state: "Any powered device, other than the system referred to in Article 11.6, which is capable of altering the configuration or affecting the performance of any part of the brake system is forbidden."
Had there been any nefarious behaviour by a team in running a braking system that was against the original regulations, then throwing in a mid-season regulation change would not have been the first course of action.
Instead, the FIA would likely have issued a Technical Directive, which would have gone to all teams and alerted rivals to something being amiss elsewhere.
