Bernie Ecclestone says a dispute between Pirelli and the F1 teams means the sport might not get wider and faster tyres for 2017.
It has been reported that while radical changes to the chassis rules are scheduled to arrive for 2017, a new engine formula might need to wait until 2018.
But the F1 supremo told Auto Motor und Sport: “We want the new engines in 2017 as well.”
As well as more power and downforce, some of the slashed laptime for 2017 will also come courtesy of Pirelli, who have agreed to build wider tyres.
But at the moment, F1’s official supplier cannot get the teams to agree a way forward regarding a suitably fast car for tyre testing.
“We want cars that are and look more aggressive,” Ecclestone admitted. “And one of the ingredients is wider tyres.
“We have asked Pirelli to build these tyres — it was not their idea. But the tests are a matter between the teams and Pirelli.
“If there is no testing, Pirelli will continue to build the tyres we have now,” he warned.