Michael Schumacher has renewed his attack on Pirelli's current specification of tires, claiming that racing with them is like driving on "raw eggs."

The seven-time World Champion criticized the rubber after the Bahrain Grand Prix when he suggested that drivers were not being able to push their cars to the limit because they needed to conserve their tires too much. Although Schumacher has been a lone voice in complaining about the tires, with other drivers happy to accept the challenge thrown at them, the German stands firm that the situation is not good.

"I just think that they're playing a much too big effect because they are so peaky and so special that they don't put our cars or ourselves to the limit," Schumacher told CNN in an interview that was part of its preview of this weekend's Spanish Grand Prix. "We drive like on raw eggs and I don't want to stress the tires at all. Otherwise you just overdo it and you go nowhere."

Pirelli has said numerous times that it is producing the kind of tires that teams have asked it to, with high degradation proving to be a key factor in helping spice up the spectacle.

Despite his criticism of the tires, Schumacher is still positive about the progress being made by Mercedes and thinks that more wins this year, following Nico Rosberg's first career triumph in China, could be on the cards.

"We have luckily got one win under our belt," he said reflecting on the campaign. "I was a bit unlucky in that race as we could have got a 1-2 without doubt, but it proves that we have made a huge step because you have to consider where we came from last year – it was not what we were really looking for.

"Starting the Silver Arrows new generation, for two years we had medium success and finally we managed a victory. I am pretty sure we can have other good races this year, being on the podium and maybe being on top of the podium."