Ferrari has opted to race its SF71-H in Mexico equipped with the car’s old floor following a comparative test on Friday in which the updated component did not prove more efficient.
The Scuderia had introduced its revised floor in Austin, but a lack of dry running at COTA did not allow for a relevant comparison.
However, Friday’s free practice running in which the new floor was tested once again did not demonstrate its advantage, compelling the Italian outfit to stick its original configuration.
"It was an interesting morning," said Sebastian Vettel. "We learned a lot and we're sticking to the old package."
Like most of his colleagues, the German driver pointed to tyre management as the day’s main challenge, and one that will likely persist for the remainder of the Mexican GP weekend.
"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," he added.
"The difficulty is you don't have any grip. So we're sliding a lot," he continued.
"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 lap time.”
As teams progressively come to grips with… the lack of grip, performance will evolve, and so will the running order according to Vettel.
“I think everybody still has something to step up tomorrow,” he said.
“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 lap time."
Gallery: The beautiful wives and girlfriends of F1 drivers
Keep up to date with all the F1 news via Facebook and Twitter
