Bottas was nursing "severe" tyre damage during Russian GP
Valtteri Bottas was nursing "pretty severe" damage to his front tyres as he held off Sebastian Vettel in the closing stages of the Russian Grand Prix, his Mercedes team has revealed.
The Finnish driver had dominated the early stages of the race at Sochi and appeared in control at the front when he suffered a major lock-up at the tricky Turn 13 on lap 38.
Although it was not clear from television footage how bad his tyres were, Mercedes said its data in the pits indicated that the situation was quite serious, which set up an intense finish as Vettel closed in to challenge.
Onboard TV footage at the end of the race showed Bottas' steering wheel was shaking heavily.
Mercedes motorsport boss Toto Wolff said: "He locked both front tyres and flat-spotted them, and our metrics showed that it was pretty severe damage to the tyres, which harmed his performance at the end.
"It was a bit of a stressful moment, but he kept it together. You could see the pace was still good enough, sector one was obviously very good, but in sector two he was able to fight back and there was the odd tenth he lost. But on the next lap around he was good.
"So it wasn't all plain sailing, and obviously again backmarker traffic was an issue. Sometimes it went against us, but with Felipe [Massa at the end] – thank you very much, I have to get him a beer – it was in favour of us but that is how it goes."
Bottas explained that the lock-up happened as temperatures began to drop in his front tyres, and the moment briefly took him out of his comfort zone.
"I definitely lost some time during that lap with the flat spot," he said. "The team was [previously] asking me to go forward with the brake bias, giving advice just to help the tyre temperatures.
"Then I had the flat spot so I had to go rearwards. I also had a little bit of traffic during that point.
"This track, it's so special about the rhythm. If you find the rhythm then you can be so quick here, and get consistent lap times and be on it. But if you lose it, it always takes a few laps to get it back here.
"So I kind of lost the rhythm for a bit, plus the backmarkers. Once I was in free air again, able to focus on my job itself, I managed to get the tyre temperatures back up and pick up the pace.
"I was also asking for a bit of radio silence from the team, for me to just to just get on with it really, for me to focus on every single corner, making it every lap perfectly, and losing minimum time with the backmarkers. And that helped."
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