Mercedes explains cause of Bottas’ botched pit stop in Bahrain F1 opener

Mercedes has explained the reasons for Valtteri Bottas' slow pit stop during the season-opening Formula 1 Bahrain Grand Prix.

It occured on Lap 30 when Bottas made his final stop of the race from third place as he looked to undercut Red Bull's Max Verstappen.

The Finn was left stationary for 10.9s when his front right tyre proved difficult to remove from his car.

Mercedes technical director James Alisson revealed the slow stop for Bottas was caused by one the gun men's “initial misplacing of the wheel gun”.

“One of Valtteri’s pit stops didn’t go so well,” Alisson explained. “We lost a lot of time in it. What happened? 

“When the car came into the pit stop box, Valtteri came in very neatly, positioned the car neatly and well, which is always a help for the pit crew, but sadly one of the gun men went onto the wheel, started to disengage the nut, loosened the nut but then started to withdraw the wheel gun just a little bit too soon before the nut had spun off its thread and because it was still offering some resistance at that point, as he withdrew the wheel gun, the socket on the wheel gun started to disengage from the nut and then started to spin round, we call it machining the nut because it starts to chip away at the edges of the nut and destroy the nut, a bit like when you are using a screwdriver and you don’t have it lined up properly, and you start to sort of damage the screwdriver slot.

“So, as he pulled away the gun machined away at the nut and it didn’t actually come off its mountings. 

“He went back in to deal with it but the gun recognises or is designed to recognise when it has done a gunning off action and it automatically shuttles the gun so that it is then in doing up mode and so when he went back on to finish the job of taking the wheel nut off, the gun is now in doing up mode and instead of undoing the nut, it is doing it up again and the subsequent sort of follow on mess of that is what causes something which is normally a beautiful two-second pit stop, causes it to then collapse into something that haemorrhages lap time and seconds in the pit lane.

“But all of it was caused by that initial misplacing of the wheel gun, machining the nut as the wheel gun came off.”

Bottas went onto finish the race in third, some distance behind eventual race winner and Mercedes teammmate Lewis Hamilton.