Michelin insists 13-inch tyres a no-go

Michelin has once again emphasised that their bid to return to Formula 1 is entirely depended on the sport changing its tyre specifications.

The current F1 tyres are 13 inches, but there has been a lot of talk that it could be changed to at least 18-inches after the 2016 season.

Michelin is in the running with Pirelli for the 2017 tyre supply contract, but the French company's motorsport head Pascal Couasnon warns they will only return if F1 agrees to make changes.

"If the sport decides to stay with 13 inch, we respect it but it would not make sense to us," he told Reuters.

He added: "That’s where we are going to wait for the next time (the contract is up for tender)."

Michelin left Formula 1 at the end of the 2006 season, but they are eager to return and produce tyres that last longer than the current ones produced by Pirelli.

"It’s not the message we want to give which is 'we’re going to invest a lot of technology to make a tyre which doesn’t last'," he said.

"I respect the strategy of my competitors but that’s not really the image and philosophy of Michelin.

"We can create pitstops with some other ideas but what Michelin would like to deliver first is a tyre where the driver has fun and is tired at the end of the race. Today they are not."

Meanwhile, motorsport director Paul Hembery says if F1 is going to make changes then they should not be fixated on a move to just 18 inches, they should rather go for a bigger step forward.

"To be honest the only appetite for going to 18, or something else, has come from external factors," he told Autosport. "The teams are actually very consistent by saying they want to stay with 13 and you can look at it two ways.

"I could sit here and say 18, to be honest, isn't relevant at all because that's what we put on our standard cars. In reality, if you want to do something dramatic, you'd sit on 19 at least, but probably 20 or 21 because that's where the top-end [road] cars are these days.

"So if you're doing it, you'd want to make a huge jump. The majority of our circuit racing is done on 18-inch tyres already, so 18 isn't that unique."