The loss of Michelin rubber has probably hurt Renault the most of all Formula One teams in 2007. Renault and Michelin closely collaborated and complemented one another, resulting in back-to-back world championships. Renault's poor performance in Australia is closely related to the difficulty in getting adjusted to Bridgestone. Renault's engineering director Pat Symonds:
"The first race may have quantified the performance deficit, but we were already well aware that our level of performance was not adequate," he noted. "Therefore, we have been focusing for a number of weeks on assessing where the lack of performance lies. "We are not dealing with a fundamental handling vice, as both drivers have said the car is reasonably well-balanced.
Our concentration is therefore on getting the most out of the [Bridgestone] tyres, but first and foremost on aggressive development of the car's aerodynamics. We know that our performance is not where it should be, and the challenge now is to get on with the job and sort it out."
That quote is from Crash.net via Yahoo. I think most all F1 observers were surprised at Renault's lack of pace at the Aussie GP. One question would be: Did BMW's performance improve a lot or did Renault's fall a lot?