Ferrari will not use the new floor it brought to Mexico for the remainder of the weekend. The floor was first trialled in Austin last weekend but it did not race, with Sebastian Vettel stating the new-found pace from Ferrari in the US came from taking away upgrades.
The floor was trialled once again in Mexico City on Kimi Raikkonen's car. However Sebastian Vettel confirmed that it has decided not to keep the floor for the remainder of the event: "It was an interesting morning," said Vettel. "We learned a lot and we're sticking to the old package."
Ferrari appeared to struggle to compete with Red Bull, who ended the session over one second ahead of the Maranello outfit. Ferrari's rivals Mercedes also had issues, with both teams suffering to find pace on the fast degrading hyper soft tyre.
Renault was also strangely ahead of the Italian squad, and was the closest team to Red Bull at the end of Friday. However, Vettel is expecting both Mercedes and Ferrari to bounce back stronger on Saturday.
"Everybody's sort of on the limit with tyres and trying to get them to work in order to slide less, with the exception maybe of the Red Bulls," the four-time world champion said. "The difficulty is you don't have any grip. So we're sliding a lot.
"The problem is if you don't have any grip and downforce, because the air's so thin, you don't get the tyres to work and when the tyres don't work it's really tricky. So that's why I think sometimes you can see quite big jumps in laptime. If you don't get it right then you're quite far off the pace. I think everybody still has something to step up tomorrow.
"The key will be the tyres. If you have 1, 2, 3 or 4km/h more in a straight line I don't think that will be detrimental. But I think it will be much more important to get the tyres in the right window because then around here you can easily get two, three, four, five tenths. Quite a lot of laptime."
Bahrain International Circuit - Winter testing