Pirelli could scrap its proposed 2020 tyres.
The teams and drivers were nearly unanimous in their disapproval of the 2020 prototypes when they were tested for the first time in US GP practice.
"It is not a positive step, but we have agreed to take a few days for the analysis," Red Bull team boss Christian Horner told Germany's Motorsport-Magazin.com.
Pirelli's goal was in part to make the tyres less susceptible to overheating. 1997 world champion Jacques Villeneuve thinks that is one of the main factors affecting the F1 show.
"It's a big problem right now that Pirelli has to deal with," he told Le Journal de Montreal.
"The reason the cars can't follow is because they lose downforce, and when that happens, the tyres overheat."
Ferrari team boss Mattia Binotto says Pirelli has failed to address that problem with the 2020 design.
"The tyre is not faster and not better on the wear side," he said after Sebastian Vettel and Charles Leclerc tried the 2020 tyres in Austin practice.
"We do not prefer the tyre because the targets have not been met."
Pirelli boss Mario Isola, however, said the initial complaints from the drivers should not be immediately taken as gospel.
"It's not that I do not trust the drivers," he said. "We can only look at the data. We have the first indications now and we still have a lot more work to do."
The drivers will get their next taste of the 2020 tyres after the season finale in Abu Dhabi.
"Now we need some adjustments to the cars to use the tyres better," said Isola.
