The rear wing choice at Baku is much more complicated than usual because of the track’s combination of extreme low- and high-downforce sectors. This year brought an extra dimension for Red Bull, as this was the last race before the FIA’s new protocol for measuring wing flexibility came into effect and there was the threat of Mercedes protest in the air.
The new protocol followed complaints from Mercedes that in the Spanish GP the Red Bull wing could be seen flexing downwards and back at speed on the straight, thereby reducing drag but still giving full downforce as it came back up at the lower speeds of the corners.
From the French GP on-board camera analysis would be used, together with 12 key markings teams would be obliged to make to specified parts of the wing to aid detecting any flex. The FIA would also reserve the right to test at 1.5 times the regulation load (currently 1000 Newtons, with no more than 1 degree of flex allowed) to measure any non-linear behaviour. The wings invariably see more load at high speed (up to 4 tonnes) than can be replicated by the FIA’s static load test, hence the motivation for that non-linear flexing behaviour once past the regulation load threshold. For the first month of the new protocol, a 20% tolerance will be granted.