Toto Wolff admits: ‘We made a mistake with George Russell’

“We have to take our disqualification on the chin,” read a statement from Toto Wolff, after George Russell’s Belgian Grand Prix-winning Mercedes was found to be 1.5kg underweight after the race. “We have clearly made a mistake and need to ensure we learn from it. We will go away, evaluate what happened and understand what went wrong. To lose a 1-2 is frustrating and we can only apologise to George who drove such a strong race.”

The cars must weigh at least 798kg when empty. They must also have enough fuel left in the tank for the FIA to take at least a 1kg sample if required. When Russell’s car was weighed before any fuel sample was taken it was already 798kg. So after around 1.5kg of fuel was removed for the sample the car was underweight by that amount. The FIA has no alternative but to disqualify in the absence of any mitigating circumstances. The team provided none.

It has been suggested that the greater wear on the one-stopping tyre (on a day when no one expected to one-stop) over a less worn two-stop tyre could account for the amount by which Russell’s car was underweight. Especially so since at Spa the cars do not do the usual slow-down lap, picking up marbles offline to increase the weight. Because of the length of the circuit, the cars simply turn right into the pitlane from La Source.

When new the front Pirelli weighs 10.7kg, the rear 13.3kg, making a total new tyre weight of 48kg. The average weight loss for a tyre after a stint is circa 8-10%. But obviously this varies with the length of stint, circuit characteristics and how hard the driver has pushed. But with Russell’s 34-lap stint on his final set of hard tyres (compared to a typical stint of 14-18 laps for a two-stopper), it’s quite conceivable that it was only the difference in wear which took the car below the legal weight. Further details are expected after the team has conducted its own investigation.