Mercedes is investigating an unexpected loss of performance at Sepang after an upgrade to its W17 failed to deliver the improvement the team anticipated. Team principal Toto Wolff said Mercedes had expected the package, one of its few major upgrades, to be worth about three tenths of a second, but the car appeared to have gone backwards by several tenths instead.

“You’re expecting three tenths to kick in and it looks like [we’ve gone] three or four or five tenths backwards,” Wolff told Sky. He said the result marked the first time this season Mercedes had missed the top three, and that it had done so by a considerable margin. “So it’s odd, but I guess we will find a solution.”

Wolff said the unusually abrasive asphalt at the Sepang circuit, along with the heat, had made it difficult to assess the new package. Mercedes encountered car behaviour on Friday that it had not experienced during the year. The car looked promising in the morning, but qualifying brought a return to earlier performance levels, with no pace, he said.

“It’s very difficult to understand,” Wolff said. “We have been a little bit caught out on Friday with some car behaviour that we didn’t see all year.” He added: “But then you can say it’s very hot and the Tarmac is very different to all the tracks. It looked really good in the morning. We seem to have, at least with Kimi, made a step in understanding. And then qualifying was a little bit back to what we saw before, just no performance.”

Mercedes has identified two specific handling and speed concerns. Wolff said the car appeared to have too much drag, costing time on the straights, particularly relative to Max Verstappen. In the low-speed Turn 2, he said, the car was unable to turn properly because of excessive understeer. Both issues were unlike what the team had seen over the course of the year.

“It looks like we are very draggy because it’s the first time that we’re losing a lot of time on the straights to, especially, Max,” Wolff said. “Then through the low speed, turn two, we are not able to turn the car. There’s just too much understeer. So overall, things we haven’t seen we haven’t seen all year.”

He said other causes may also be contributing and that the team still needed to work through the data. Wolff maintained that he believed the upgrade itself was effective, but said Mercedes needed to determine why it had not worked at this circuit. “Something else is going on and we have to understand,” he said. “This is now [about] working through the data and putting our heads together because we still believe that the upgrade works we just need to understand why not here.”

The report was published by RaceFans on Oct. 3, 2026, at 10:38, and was written by Keith Collantine. The article identifies the event as the 2026 Bahrain Grand Prix in Malaysia and says Verstappen took his first pole of 2026 ahead of Lewis Hamilton and Kimi Antonelli in Sepang. It also notes that Antonelli led the Red Bulls in final practice. Separately, Haas acknowledged that a set-up mistake on Oliver Bearman’s car made one session a “total waste of time.” RaceFans was established by Collantine in 2005 as F1 Fanatic; he had worked as a motoring journalist and began running the site full-time in 2010.

Based on reporting by RaceFans.