Michael Schumacher is refusing to let Pirelli off the hook after launching another attack on the tyre manufacturer by claiming their rubber is like driving "on raw eggs".

The seven-times world champion bemoaned the quality of the tyres this season following the Bahrain Grand Prix last month.

After the race Schumacher said: "The main thing I feel unhappy about is everyone has to drive well below a driver's, and in particular, the car's limits to maintain the tyres. I just question whether they should play such a big importance, or whether they should last a bit longer, and that you can drive at normal racing car speed and not cruise around like we have a safety car."

That prompted a disappointed reaction from Pirelli's director of motorsport, Paul Hembery, who claimed other drivers were "getting on with the job and getting their tyres to work".

Schumacher, though, has refused to let the issue lie and told CNN ahead of this weekend's Spanish Grand Prix. "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. We drive like on raw eggs and I don't want to stress the tyres at all. Otherwise you just overdo it and you go nowhere."