Pirelli has made it clear there is "no chance" of delaying the introduction of new 18-inch wheels into Formula 1 next year.

That warning comes after teams opted to reject the tyres the Italian supplier had developed for 2020 for aerodynamic reasons, meaning F1 will race with last season's spec again this year.

Already, work on the new 18-inch wheels is well underway with all 10 teams creating mule cars to try and give Pirelli a representative base for the significant change.

But if those teams are unhappy with the end result, motorsport boss Mario Isola says they'll have to grin and bear it.

"There is no chance of going back to the 13-inch tyres," he stated to Germany's Motorsport-Total.

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"Fortunately, we already ran three tests in 2019. The initial feedback for the 18-inch tyres was good, so I don't expect any surprises this year.

"When everything is new, you usually expect a problem and that you might have to stop for half a day or more but we had no problems at all."

In fact, work on the 18-inch tyres will continue this week with Charles Leclerc driving for Ferrari at Jerez before heading to Barcelona for pre-season testing on February 19.