The majority of teams oppose the new technical regulations for 2021 being proposed by Formula 1, BBC Sport can reveal.
Six of the 10 teams indicated in a questionnaire organised by Ferrari, Mercedes and Red Bull that they do not agree with the plans as they stand.
Only Alfa Romeo, McLaren, Renault and Williams preferred the proposed new rules to the existing ones.
And two of those four have subsequently proposed changes to the 2021 rules.
The parties will meet on 16 October to discuss the issue further.
There is a deadline of 31 October for the 2021 technical rules to be decided and so far there has been no indication from the FIA, motorsport's world governing body, or F1 that they will back down.
If a compromise cannot be reached, Ferrari have the right to veto the 2021 rules package, but it is understood the Italian team would prefer for matters not to get to that stage.
- Mercedes eye F1 history in typhoon-hit Japan
- Japanese GP first and second practice results
- I'm not here to be liked: Verstappen on hard racing and dirty driving
What prompted the questionnaire?
Ferrari, Mercedes and Red Bull sent the questionnaire around following a meeting at the Singapore Grand Prix last month at which the teams were shown the latest draft of the 2021 rules.
According to senior figures, this introduced more severe restrictions on design freedom and led to a number of teams expressing concerns.
At the meeting, FIA president Jean Todt said he did not want to impose a set of rules without agreement. The Frenchman asked for teams to indicate their positions on the various issues and suggestions for alternatives if there were any.
The questionnaire asked about 10 questions, including whether teams preferred to press ahead with the proposed 2021 rules or stick with the existing regulations. In the case of the new rules, it also asked whether there should be more design freedom, and what teams felt about standardisation of parts.
Only Alfa Romeo, McLaren and Renault immediately indicated they would choose the current 2021 proposal, while Williams did so a number of days later.
The teams' responses were communicated to the FIA World Council, the sport's legislative body, by Ferrari team principal Mattia Binotto on 4 October.
Since then, there has been a meeting of the technical working group of the FIA and teams' leading engineers, at which Alfa Romeo and McLaren were among those to propose changes to the 2021 rules as they stand.
What are the proposed 2021 rules?
F1, under the leadership of former Mercedes team boss Ross Brawn, has been working for more than two years on a new set of technical regulations, with the aim of closing up the field and creating better racing by making it easier to overtake.
A budget cap has already been agreed, and has the support of the top teams, but discussions over the planned changes to the cars are ongoing.
F1 wants to change the way cars produce aerodynamic downforce to make it easier for drivers to follow each other and therefore overtake, with the proposal being for a greater proportion of the overall downforce of the car to be produced by the underfloor instead of the front wing and various shapers around the upper bodywork.
The idea is for the degree to which performance is affected by turbulent air from a car in front to be greatly reduced.
F1 also wants to limit the design freedom available to teams in order to make it harder for those with more resources to create cars with such an advantage over the others.
It is hoped this would end the two-tier nature of F1, which has a closely packed midfield well over a second a lap slower than the top three teams - Mercedes, Ferrari and Red Bull.
What are the objections to the new rules?
The top teams have concerns about the existing rules for a number of reasons:
- The possibility of unintended consequences, as well as the risk of introducing so many significant rule changes in one go while moving away from regulations that have been developed organically over many years. F1 is introducing an entirely new car design, a number of standard parts, and changing tyre size from 13-inch wheels to 18-inch wheels and much lower-profile tyres, which have a significant effect on the design of suspension and aerodynamics.
- Changing the rules could lead to the field being spread out further rather than closed up, especially as the top teams will be able to devote their much greater resources to the 2021 rules package next year before the budget cap comes into force.
- They argue that the technical rules are not the main cause of problems when cars race closely together, and claim the fragile nature of Pirelli's tyres - which overheat easily when drivers push hard or follow another car - is a far bigger issue.
- They believe the proposed 2021 rules are too restrictive and will lead to the cars all looking the same - even more than is the case at the moment.
- They are opposed to proposals for standard parts, which they believe not only go against the philosophy of F1 but will also not reduce costs and lead to heavier and lower-quality cars.
Some of the smaller teams - as well as some within F1 - believe Ferrari, Mercedes and Red Bull are trying to protect their competitive advantage by keeping the rules the same. The top teams deny this is their motivation.
The six teams who directly objected to the current 2021 proposal are the top teams and what some regard as their effective satellites - Toro Rosso are Red Bull's junior team, while Haas and Racing Point buy large numbers of parts from Ferrari and Mercedes respectively, and have a history of voting with their partners.
What happens next?
Ferrari, Mercedes and Red Bull presented their own proposal for 2021 to the FIA and F1 on Thursday. This was based on the F1 proposal, taking what they consider the more positive aspects and adding scope for development to ensure the cars would not all look the same.
Under the existing governance structure, the FIA and F1 can simply impose the rules on the teams.
Todt has always preferred to run the sport with a conciliatory and collegiate approach, in contrast to the one often espoused by his predecessor, Max Mosley.
And trying to impose the rules runs the risk of Ferrari using their veto - which would effectively force the FIA to stick with the existing regulations.
But the risk for Ferrari is the understanding that if they exercise the veto, they will lose that right under new governance structures that have to be agreed before 2021.