Mark Webber was fastest in the second practice session at Spa.
The teams made the most of an hour’s running without rain and the times tumbled as the drivers used first intermediate tyres and then slicks.
Bruno Senna returned to the track after his crash in first practice and immediately went third fastest. He was briefly quickest of all as he traded times with team mate Vitaly Petrov.
Fernando Alonso was the first driver to use the medium slick tyre and took the fastest time off Webber by over four seconds.
With the prospect of fresh rain arriving the drivers hurried up their programmes to get some running done on soft tyres. Nico Rosberg used a set to go fastest.
But it was Webber who set the best time before the rain returned, setting the mark at 1’50.321.
Alonso was second-fastest ahead of the McLarens of Jenson Button and Lewis Hamilton.
Felipe Massa was fifth ahead of Rosberg and Sergio Perez.
The two Force Indias of Nico H?â??lkenberg and Paul di Resta were separated by two hundredths of a second in eighth and ninth, with Sebastian Vettel completing the top ten.
2011 Belgian Grand Prix
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