How Bottas finished second in Spain on ‘extremely marginal’ F1 tyres 

Mercedes has revealed the challenge Valtteri Bottas faced to ensure he finished in second place at last weekend’s Spanish Grand Prix despite running on “extremely marginal” Formula 1 tyres.

In a bid to recover the position he lost to Sebastian Vettel at the start of the race, Bottas pitted early on Lap 19 to switch onto a one-stop strategy. Although he faced the prospect of needing to complete 47 laps on Pirelli’s Medium compound, the Finn secured second. 

His bid was aided when Ferrari was forced to switch Vettel onto an unplanned two-stop strategy with the German struggling with excessive tyre wear - dropping him to fourth - but Bottas still had to hold off the charging Max Verstappen behind. He kept the Red Bull driver at bay but revealed after the race he had nearly no rubber left on his tyres.

"There was nothing left on the tyres at the end of the race," Bottas said. "It was down to the canvas and for me it always felt like, when I was trying to save it, the next few corners I had no grip because I lost so much temperature. 

“When there is no surface left on the tyre it is so easy to lose temperature and if you let it switch off you are done and you are going to start locking up.”

Speaking in the team’s post-race debrief video, Mercedes chief strategist James Vowles explained the “incredible job” Bottas did in order to manage his badly-graining tyres, particularly the front-left. 

“The last few laps of the race for Valtteri were very, very tense,” Vowles said. “We know that the front left tyre would be very much down to nearly zero percent rubber remaining and it’s a very difficult call to know what’s going to happen. 

“He had eight seconds of race time relative to the Red Bull behind and what we were trying to do very delicately was use some of that race time to slow down in some of the key corner sequences to make sure we looked after that tyre while not losing temperature that was left on it. 

“It was a very delicate balance and I really cannot understate this, Valtteri did an incredible job. We put him in a very difficult position and he dealt with it absolutely perfectly, taking that tyre just to the end of the race.”

Vowles added Mercedes never planned on calling Bottas into the pits in the closing stages because the team had complete faith in its driver to make it to the chequered flag in second. 

“It’s fair to say it was extremely marginal,” he continued. “I think if the race had been a lap or two longer we could have been in big, big trouble. Valtteri did a very good job just managing that weak tyre that had to be looked after whilst to maintain the performance. 

“We were never going to bring Valtteri in during the last few laps because we had the confidence that he was just going to make it. We have a number of metrics from the car which aid us in that decision. You can see for example what vibrations the tyres are experiencing. 

“The amount of managing Valtteri had to do was different depending on whether he had traffic in front and whether he had to pass a back marker. At the end of the race it was all about using some of that race time that he had accumulated to Verstappen just to make sure we absolutely made it to the end of the race.”

Tyres were a talking point throughout the weekend after Pirelli introduced a modified version of its F1 tyres with a reduced tread in Barcelona following concerns raised by teams over severe graining and blistering throughout pre-season testing at the re-surfaced venue. 

Vettel initially suggested the changes had hurt Ferrari more than F1 rivals Mercedes but later changed his mind after completing a back-to-back comparison using the regular tread tyres in the first in-season test in Barcelona. Mercedes had earlier dismissed that Pirelli's revisions were made to its benefit.