Pirelli and Michelin go head-to-head for 2017 Formula 1 tyre deal

Pirelli motorsport boss Paul Hembery told reporters in Austria that there were only two bidders for the three-year contract from 2017 and independent sources confirmed to AUTOSPORT this was the case.

Michelin's bid is based on switching from 13-inch to 18-inch rims, as is currently the case with its supply to Formula E, and longer-lasting rubber.

However, Pirelli's proposal is more flexible, with the Italian supplier saying it will follow whatever rules the FIA chooses to enforce.

"Our bid is to follow the rules," said Hembery.

"An example would be an engine manufacturer coming in and proposing a five-litre V8 then acting surprised when the sport says it wants a 1.6-litre turbo.

"We can only reply to the rules and we've said we will supply what they want.

"Do you want to do 20-inch? We'll do 20-inch.

"Tyres that last the whole race? We'll do that.

"Tell us what you want and we'll do it.

"We do what the sport asks from us. It's not our position to change the rules.

"We can have suggestions, of course.

"At the moment it's very clear that the size of the tyre is set by the FIA together with the teams and the promoter and it sets a certain type of tyre.

"They are still asking us to help assist create a number of pitstops. If that changes, of course we can do that as well."

Pirelli took over from Bridgestone as F1's control tyre supplier at the start of the 2011 campaign.

Michelin left the championship at the end of 2006 after a five-season tyre war with Bridgestone.