The second session was a lot quieter than the first, although Williams had another serious issue with their tyres. Pastor Maldonado's wheel nut popped off, the car ran over it and picked up a puncture, whilst the nut itself went rolling off down the track. Luckily it didn't hit anyone or anything else, but it's the second race weekend in a row that Williams have had tyre safety problems. Meanwhile, Vettel had something of a KERS issue but it didn't stop him going fastest, with Webber behind and Romain Grosjean best of the rest.