Pirelli has tried 2017 Formula 1 tyre concepts on GP2 cars

The Italian tyre manufacturer's motorsport boss Paul Hembery concedes Pirelli now faces "a big challenge" after finally being given clear testing guidelines on development of its 2017 rubber.

On Wednesday, the World Motor Sport Council signed off on changes to the sporting regulations that will allow Pirelli 25 days of testing for this year, 2017 and '18.

Pirelli, however, has long been conducting work alongside recent talks to amend the rules in a bid to get a head start on the wider 2017 tyres.

"We've been doing a huge amount of work," Hembery told Autosport.

"We've supplied sets of windtunnel tyres, we're looking to supply the first sets of rig tyres, we've been doing a lot of integrity work, doing a lot of profile work.

"There's been a lot of work on the simulation side up until now, and physical testing on indoor rigs.

"We've also done limited tests on GP2 cars looking at some new concepts, so work has been ongoing.

"It's now a case of bringing it all together, which will obviously happen later in the year."

Although GP2 cars were deployed for what Hembery described as "initial testing" at Barcelona, he added that "lack of heat generation meant they were not sufficiently representative" for substantial ongoing use.

It is anticipated teams will have the modified 2015 F1 car required for Pirelli this year ready by the end of July, following which Pirelli will then attempt to squeeze in its permitted 25 days.

"We'll certainly try to. Of course it depends on the availability of the modified cars, and we'll know in the next couple of weeks who is able to do that for us," added Hembery.

"There are between five and seven teams who have suggested they would be able to do it, which is a positive.

"You can imagine, though, there is also a lot of work to do on the wet tyres as we've two wet compounds to do, and with wider tyres you have more issues with aquaplaning.

"We're now in the phase of stabilising all our test plans, which is something we have been doing this week, and then we can convey those to the teams who will get involved."

With the first pre-season test of next year around nine months away, time is pressing on Pirelli.

"It's a big challenge," said Hembery.

"We're at least happy to have some clear guidelines going forward, and now we have to deliver what the sport is asking us.

"We want to give the sport and the drivers what they are looking for, and we're working in that direction.

"The team is very motivated and full of ideas, so it's great we now have the final part of the jigsaw in place to allow us to do our work."