Our forged Magnesium alloy rear wheels measure ø625mm (the same as the fronts) and 445mm wide (80mm wider). Each rim is barcoded and paired with a specific tyre, and once the tyres are fitted, they go into our stacks, to be warmed in their electronic heated blankets. In a pitstop, rear wheels are slightly harder to fit than front wheels, because they’re heavier – 16kg vs 14kg – with the captive nut buried slightly deeper within the well. The gunner on the outside rear corner has the toughest job: he can’t see the car approaching.