Adrian Sutil has reinforced the view that three or even four-stop pit strategies will be commonplace in 2011.
The Force India driver did a race simulation at the Barcelona test on Thursday.
"We tried to do a two stop strategy," he told Germany's Auto Motor und Sport, "but it's impossible."
He lamented the extreme degradation of the Pirelli tyres and noted that "the only positive is that it's the same for all".
Ferrari's Felipe Massa has a slightly different view.
"With a fresh set of tyres I can immediately feel the grip, which was different for me with Bridgestone," the Brazilian is quoted by O Estado de S.Paulo.
Massa acknowledged, however, that there will be "three or four" pitstops per race.