Pirelli's testing data has been constrained by the power unit issues facing Renault-powered teams so far this pre-season.

Renault's issues have seen limited running from Red Bull, Lotus, Toro Rosso and Caterham, with Pastor Maldonado saying on Thursday that the engine is still not at 100%. For Pirelli, the two tests in the heat of Bahrain should help test the tyres in more representative conditions than Jerez in January, but motorsport director Paul Hembery admits it has yet to see representative performance from those four teams.

Asked during an exclusive interview with Crash.net if Renault's problems had impacted on Pirelli's attempts to learn about its new tyres, Hembery replied: "A little bit of course, because you don't know what that chassis in particular is going to create when you start running a lot of laps.

"From the other point of view we've picked up on some positives. If you go round the track in the evening you're seeing a lot less marbles - which was one of the objectives of the season - so it looks as if we're in the right direction for that.

"It's one of those things that when you're running with just one or two cars you don't really know if you've achieved what you want until you actually get here. Wear levels are dramatically reduced; we still have a thermal degradation which in any case you would expect here because of the type of track. It's a traction track and a lot of wheelspin if you're going to get it is going to be here and there are quite high temperatures, so we're pleased with that.

"The step in performance level between the four compounds is a good step. They're not too close together, so that does mean if we make the right choices we can deliver what the sport is asking us to which is the two to three stop races."

And Hembery also said there were no plans to make any changes to the tyres ahead of the first race in Melbourne.

"Nope, we're happy, very happy. But we're very conscious of the fact that the sport and the cars can change very rapidly. Even if you compare this week's testing with last week's, I'm quite sure you'll see some significant changes in performance. So we have to be pragmatic and say 'we're happy, but...'"