MELBOURNE, Australia -- Mercedes admits it got its math wrong at the Australian Grand Prix, costing Lewis Hamilton a possible victory at the opening round of the season.
Hamilton appeared to have the race under control for the first 25 laps, but he lost the victory when Sebastian Vettel made up a large chunk of time by pitting under a Virtual Safety Car [VSC]. Hamilton had made an earlier pit stop in normal racing conditions to cover off the threat from Vettel's Ferrari teammate Kimi Raikkonen and was therefore vulnerable to a Ferrari pincer movement.
Vettel was leading after the stops of Hamilton and Raikkonen but was losing time to both on older tires. His strategy hinged on a Safety Car or VSC coming into play, and it paid off on lap 25 when Romain Grosjean's Haas came to a halt in a dangerous position with a loose wheel nut.
The resulting VSC allowed Vettel to pit while the rest of the field circulated at a reduced lap time, meaning his pit stop only cost him 11 seconds relative to Hamilton, rather than the usual 20-plus at normal racing speeds. Vettel emerged from the pits 0.682s ahead of Hamilton and held the lead for the rest of the race.
At the time, it appeared as though Hamilton had been caught out by an unfortunate sequence of events, but in fact Mercedes believes the situation could have been avoided. After his pit stop, Hamilton was told to stay within 15 seconds of Vettel as his engineers believed that gap would be enough to prevent him losing the lead in the event of a Safety Car or VSC. Hamilton duly hovered around 12 to 13 seconds off to give himself a margin but, as it transpired, it was not enough.
"Lewis did nothing wrong," Mercedes team boss Toto Wolff explained. "It was down to a software bug or an algorithm that was simply wrong.
"Our computer said 15 seconds was the necessary time in order to jump us. We were always within this three-, four-second margin. Then suddenly the cameras showed us the pit exit and Sebastian came out in front of us. We have no explanation yet."
"It could be an unlucky situation that Sebastian was just making it into the pits and was accelerating behind safety car line one and two," Wolff continued. "I don't know. This is a hypothesis at the moment. Therefore, he would have lost much less on VSC than Lewis, who had to brake pretty hard in a high-speed zone. The software or system we have been using for five years just gave us the wrong number."
With Vettel emerging from his pit stop just 0.6s ahead of Hamilton, Wolff said Mercedes should have instructed Hamilton to push harder prior to the VSC but was worried about excessive tire and engine wear.
"The only thing we could have done was try to push more after his pit stop and try to create a bigger gap," Wolff said. "But knowing that the tire needed to go another 40 laps or so, it was very important not to stretch that too much, and he was going quicker than Sebastian anyway. So the gap grew. And we knew that the gap was good enough that even under VSC we would still maintain the lead.
"If we knew it would have been three of four seconds more, we would have pushed a bit more with the tires with the risk at the end of the race -- we would have done it [if we'd known]. I think, like always in motor racing, with the VSC or normal Safety Car, sometimes you are lucky and sometimes it bites you. Today, we were bitten."