Mercedes remain confident that their rear wing is completely legal after passing new tests introduced by the FIA at the Qatar Grand Prix, with Red Bull still suspicious about their title rivals.
The two teams have been fighting tooth and nail since the beginning of the campaign and with two races left in the season, both championships are still firmly up for grabs.
In the bid to get the edge over the other, as has been the case in Formula 1 for decades, points have been made over the legality of certain aspects of both cars over the course of 2021 and, most recently of all, it's the Mercedes' rear wing that has been in the spotlight.
Red Bull, though stopping short at a formal protest thus far, appear fairly confident that the Mercedes rear wing flexes more than is allowed, allowing for greater straight-line speed as it reduces aerodynamic drag.
The Silver Arrows, though, have regularly maintained their innocence and a new test at the Qatar GP, introduced by the FIA, looks to have been passed by the current champs.
Two 35kg weights were hung at different points from the Mercedes rear-wing, to test the flex, and the team said it came through without issue, before popping a jab at Red Bull:
“The wing was rock solid. You could have hung 100 kilos on it,” a source from the German team told Auto Motor Sport.
“Maybe Red Bull will ask for 105 kilograms next time.”
Red Bull alleged that the rear wing they think is flouting the rules was changed to one that doesn't on Saturday before the test took place, something Mercedes have straight up denied.
This test will now go ahead at the race weekends to come as we close in on the final events of the season so it appears this extra sub-plot still has legs yet.