Formula One drivers expressed concern on Thursday that the sport was heading in the wrong direction with its plans for a 2017 rules revamp.
Teams have until Saturday to approve the regulations by majority vote, rather than unanimous agreement, and have already hammered out most of the details in meetings over the past few months.
The plans are for cars and tyres to be wider and more aggressive looking, making them more exciting and harder to handle while also producing closer racing.
Drivers fear, however, that aerodynamic changes will instead make it harder for cars to follow and overtake.
"You hope that the engineers who know what’s going to happen -- just like they knew with the qualifying -- I hope they are proven wrong," triple world champion Lewis Hamilton told reporters at the Russian Grand Prix.
"If they aren’t, then we’re stuck in that period for three years and for the fans, it doesn’t get any better. But those guys who made the decision have to live with it," said the Mercedes driver.
Formula One revised its qualifying format this season in a bid to shake up starting grids but the move was derided as a fiasco, by fans and teams alike, and scrapped after two races.
Hamilton's teammate and championship leader Nico Rosberg said he had hoped the teams would have second thoughts about the 2017 changes.
"Our opinion was that it's not the right direction to go," he said. "Now that's the way it is, so now all we can do is accept it and make the most of it and hope that there are going to be some surprises."
Mercedes have been dominant since the 1.6 litre V6 turbo hybrid power units were introduced in 2014, the team winning 35 of 41 races. However, rivals Ferrari and Red Bull appear to be catching up.
The Mercedes drivers views chimed with those of team boss Toto Wolff, who has said the sport should put the changes on hold because cars were already faster, performance gaps narrowing and races more exciting.
McLaren's Jenson Button and Fernando Alonso also said they felt it was worth waiting for greater convergence between the various power units before making major changes.
Haas's Mexican driver Esteban Gutierrez felt introducing wider cars and tyres was the right move but was "not fully convinced" about increased downforce "which will naturally make overtaking more difficult."