Fernando Alonso was critical of Pirelli’s tyres after the first real test day of the 2011 season on Tuesday.
"They degrade quite a lot, especially the rears, and the lap times are not consistent," the Spaniard, whose F150 Ferrari was almost a second off the pace of the chart-topping new Red Bull, said at Valencia.
Alonso is also quoted by Germany’s Auto Motor und Sport as saying exploring the car’s setup was difficult because there are not enough sets of Pirelli tyres at the test.