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Mercedes has abandoned its new floor for the remainder of Formula 1’s Belgian Grand Prix weekend following doubts over its performance during Friday practice.
The Brackley-based squad had a disappointing opening day of running at Spa-Francorchamps with both George Russell and Lewis Hamilton not feeling totally comfortable with how their W15 felt as they ended the day more than one second adrift of the best times.
Despite having made improvements with the set-up over the course of the day, the team was left baffled as to why it was losing up to 0.9 seconds on the Spa straights compared to its benchmark opposition.
It had arrived in Belgium with some confidence that, following its strong showing at the similarly high-speed Silverstone, it should have been able to maintain a similar form this time out.
The disappointing pace on Friday immediately prompted some debate about whether updates it had brought this weekend were behind its struggles.
With post-session engineering meetings on Friday evening, and work conducted in the simulator and factory overnight, not delivering a firm conclusion that the new floor was a definite step forward in performance, the team has elected to revert to its previous specification from Saturday morning's running.
That decision was also nudged across the line by the likely wet weather that is anticipated, meaning drivers’ confidence needs to be at a high while there is also an increased chance of accidents – which could put a strain on spare parts availability.
![](https://cdn.motorsport.com/images/mgl/YMdqk7n2/s1000/mercedes-w15-floor.jpg)
While the team has gone back a floor spec for now, it is understood that the team will now spend the gap before the next race evaluating whether its Friday difficulties were caused by the floor or something else.
Mercedes engineering director Andrew Shovlin had said ahead of running that the team had had good faith in the floor bringing a gain.
Speaking about the upgrades, he said: “The main thing is the floor. It's just another step of development that we've been able to bring here.
“It's also nice to get some new parts on the car, because the reality of a cost cap is you're constantly sort of patching them up, trying to repair them. Hopefully this will be a step forward."