The Brawn GP cars, which locked out the front row of the grid for the Australian Grand Prix, have been revealed to have had no weight advantage in qualifying after the FIA published a list of each car's race-start load.
With each car's minimum weight set at 605kg (including driver), the Brawns of Jenson Button and Rubens Barrichello weigh in at 664.5kg and 666.5kg respectively. This suggests an opening race stint for the pair of more than 20 laps, depending on safety car intervention.
By comparison, Sebastian Vettel weighs in at 657kg from third on the grid, with fellow second-row starter Robert Kubica at 650kg. This means that the BMW Sauber driver is the lightest car in the field, helping him to qualify well despite not showing that kind of pace in free practice.
Of the top 10 in Q3, only Toyota's Timo Glock was on a heavier fuel load than the two Brawns, although Toyota's times have been disallowed.
Nelson Piquet's Renault is the heaviest car on the grid at 694.1kg, which should allow him to run more than 10 laps longer than the Brawns, with both Nick Heidfeld and Heikki Kovalainen also tipping the scales at over 690kg.
Williams driver Kazuki Nakajima's weight has been officially declared to be 612.5kg, although it is understood that figure could be amended to around 685kg.
The 10 cars who made it through to Q3 all qualified at their declared race-start weights, plus the fuel needed for them to complete that session, while those who fell in Q1 and Q2 have been allowed to choose their start loads after qualifying.