Nico Rosberg is expecting the new Pirelli tyres to play a major role in the type of racing in the 2012 Formula 1 season after his second day of running in the Jerez test.

Mercedes has brought its 2011 car to the first pre-season test with the focus on evaluating the new tyres and Rosberg, who ended today fastest, eight tenths ahead of the best 2012 car of Lotus driver Romain Grosjean, believes that Pirelli has achieved the targets that it set itself.

"It is going to have a big impact on the racing because the compounds are closer now," said Rosberg when asked by AUTOSPORT about the new tyres. "It is difficult for me to foresee how that will go, but it will be different.

"The [the compounds] are much closer together now. Degradation is still a big issue and the rear tyre seems a bit strong. Overall, Pirelli has done a good job."

Rosberg believes the data that Mercedes has collected on the new Pirellis during the test will allow it to hit the ground running when the new car takes to the track at Barcelona on February 21.

"It's important to understand the tyres properly because there are some quite big differences to last year," he said.

"It's a good thing because now we know exactly what the car does [on the new tyres]. We will have a direct comparison when we put the new tyres on the new car."

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