Thatâs a damn fine question. I think @Wyvern is right in that the driver/team can change to inters/wets if they feel the track is unsafe on slicks. But I think in F1 at least the Start Procedure regulations make what he did in the video tricky.
At the start of an F1 race, teams are not permitted to change tyres after the 3 minute warning has gone up:
36.4 When the three minute signal is shown all cars on the grid must have their wheels fitted, after
this signal wheels may only be removed in the pit lane.
And allowing a switch to wets after the 5 minute signal but before the race start (so presumably including the formation lap) is at the discrection of the Race Director:
36.14 Only in the following cases will any variation in the start procedure be allowed :
a) If it starts to rain after the five minute signal but before the race is started and, in the
opinion of the race director teams should be given the opportunity to change tyres, the
abort lights will be shown on the Line and the starting procedure will begin again at the
ten minute point.
There is a section that talks about pitting on the formation lapâŚ
Any other car entering the pit lane during the formation laps may reâjoin the track but
must enter the pit lane after the safety car returns to the pits and start the race from
the end of the pit lane in the order they get there.
A penalty under Article 38.3(d) will be imposed on any driver whose tyre(s) are changed
for a different specification before the start of the race.
Presumably thatâs to allow for any drivers who somehow manage to trash their initial start tyres on the formation lap, but the swithc must be like for like, so you wouldnât be able to switch from softs to hards for example and claim it as your tyre change for the race. The penalty mentioned, 38.3(d), is a 10 second stop-and-go time penalty.
So basically, my reading of it, is that the entire start procedure, which includes the formation lap, is under the control of the Race Director. And unless he declares the track wet, in this example, the driver should have started the race on the tyres he had fitted, and then pitted at the end of Lap 1 to switch to Inters/Wets.
Or somethingâŚ
(sorry, this turned out to be a shit ton more than I planned to respond with. )