Listen to this article The heavier cars for this year, rather than the shift to ground effect, has emerged as the biggest difference that drivers felt in their first day of testing the new F1 cars at Barcelona in Spain on Wednesday. As a result of ramped up safety structures and the shift to 18-inch wheels, F1’s car weight has jumped from 752kg last year to 795kg this season. For McLaren driver Lando Norris, who topped the times on the opening day of practice, the extra weight has left him feeling that the cars are not as nimble as the previous generation. “The weight makes a massive difference for just the driving, how the car reacts,” he said. “It’s a lot heavier than it was last season. So it just feels a bit slower, a bit more sluggish. “It’s like running with the race fuel of last season before almost a qualifying lap in a way. You do feel it in like the braking and certain areas. The performance is not qui …