Red Bull fears that its prospects for this weekend's Las Vegas Grand Prix - which could see Max Verstappen clinch the 2024 title - have been compromised by bringing the wrong rear wing configuration to the event.
Verstappen finished second practice down in 17th place because of problems getting in a representative flying lap before the session was briefly red flagged. But even before that, Verstappen had been struggling for pace.
Engine settings and a different tyre programme were partly to blame, but the car also appeared to be some 7km/h slower on the straights than those of their rivals according to GPS data.
"We don't have another rear wing, a smaller rear wing, as we see it on our competitors," Red Bull motorsport advisor Helmut Marko said. "It would be more helpful, for sure.
"On the short run we didn't go out with a soft tyre, and the long run was only partly good," he admitted. "Some laps were competitive, but then the rear tyres were disappearing.
"There were flashes of speed, we just have to get consistency into it," he added. "On the single lap we can improve. But on the long run, the tyre wear is a problem at the moment."
Marko said there was no chance of flying in a trimmed wing in time for the race. He added that they needed to find more balance before tomorrow's final practice and qualifying sessions. "Tomorrow is a different day," he said.
"You maybe saw it a lot of times. People will be fastest on Friday or Thursday, but it doesn't mean that they are fast in the race," he explained. "We will, for sure, make a reasonable step."
"The issue for us is definitely tyre related as we have no grip and it feels like driving on ice," said Verstappen. "We struggled to make the tyres work, especially over one lap, and we were quite far off with the pace.
"On the long runs we started off a bit more competitively, but we still need to fine tune a few things," he admitted. "However, at the end of the day this is the same for everyone, so we need to understand what we are doing wrong."
Things weren't much better for his team mate Sergio Perez who ended the day in P19.
“We have some work to do over one lap, I think the long run looked a little bit more promising, but we have got to focus overnight to really try to exploit everything because we are not where we want.
"We were mainly struggling with balance in the low speed today, the rear is stepping out a lot, we came down a lot on downforce with the rear wing and it made it quite tricky.
"Especially over a single lap we need to improve and hopefully we can do that, make another step and go in the right direction."
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