Ferrari has again opted against using its new floor following more trials during practice for Formula 1’s Mexican Grand Prix.
Ferrari recently introduced an updated floor but did not race it in Austin, with Sebastian Vettel suggesting that reverting to an older specification car was behind its surge in pace.
Ferrari ran further evaluations during Friday practice in Mexico and Vettel confirmed that “we are sticking to the old package.”
Vettel finished fourth during a second practice session that finished with an atypical running order.
Red Bull dominated for a 1-2 finish, with its drivers a second clear, while Renault took third and fifth courtesy of Carlos Sainz Jr. and Nico Hulkenberg, as Brendon Hartley took sixth for Toro Rosso.
Lewis Hamilton, meanwhile, was left down in seventh position.
Vettel believes he would have been ahead of Sainz Jr. without an error through Turn 11, but lamented an overall lack of grip at the high-altitude Autodromo Hermanos Rodriguez.
“I think it’s sort of expected that Red Bull is very strong,” said Vettel.
“I don’t think we had a tidy lap, so we should have been in front of the Renaults.
“The difficulty is that you don’t have any grip so we are sliding a lot, and the problem is if you don’t have a lot of grip and downforce because the air is so thin, you don’t get the tyres to work.
“When the tyres don’t work then it is really tricky. So that is why you can see sometimes quite big jumps in lap times.
“If you don’t get it right you are quite far off the pace.
“That will be the main job to get right for tomorrow because you have one lap in qualifying.
“With the Hypersoft it should be a bit easier, but still it is tricky to keep a clean balance from the beginning to the end of the lap.”
