What in the world happened to Schumi?

Michael Schumacher’s Singapore Grand Prix came to an early end on Sunday when he crashed into the back of Jean-Eric Vergne’s Toro Rosso. The stewards investigated the incident, found that Schumacher was to blame – which he admitted – and handed him a 10-place grid penalty for the next race in Japan.

The incident occurred under braking for turn 14. Schumacher was not particularly close to Vergne approaching the braking zone. He braked visibly later than Kimi Raikkonen behind him, but still seemed to be far away from Vergne in front. Realising that his car was not decelerating quickly enough, Schumacher braked harder and locked up all four tyres, which effectively ended his chances of avoiding the accident.

Two things seem strange about the crash. Firstly, the gap between Vergne and Schumacher was significant enough that even braking a bit late should not normally have caused Schumacher to run into the back of the Toro Rosso. Secondly, Schumacher’s outside front tyre was the first to lock up. Normally the inside front tyre is slightly unloaded on the approach to a corner, and so will lock up first.

Both issues can possibly be explained by cold tyres and brakes. The crash took place shortly after a Safety Car period, during which the cars run at significantly reduced speed and therefore tend to lose temperature in their tyres and brakes. It is normal to be cautious under braking for a lap or two after racing resumes in order to get the tyres and brakes back up to temperature.

Another possible explanation is an incorrect brake bias. The driver of an F1 car can change how much braking force is distributed to the front and rear axles using a lever in the cockpit. Schumacher himself is famous for adjusting his brake bias almost every corner. Perhaps he made an error with the bias and put too much of the braking force through the slightly cold front tyres. That would certainly cause the front tyres to lock up and prevent adequate deceleration.

Another possibility, which Schumacher suggested when he was interviewed after the crash, is a technical failure on the car. But exactly what that could be is mystifying. His brakes worked. That much is evidenced by the plumes of tyre smoke generated by his four locked-up tyres. The only other obvious failure that could cause his car to brake inefficiently would be suspension-related. The car can only slow down if the tyres are rotating and in contact with the track. If he had a suspension failure that caused the front tyres to have limited grip with the track surface, that would explain the locking brakes and lack of deceleration.

What is most likely is that it was a simple driver error. On slightly cold tyres and with slightly cold brakes, Schumacher probably just braked too late and then found himself a passenger in a car that would not slow down enough. At least he had the experience to hit the middle of the back of Vergne’s car, thereby reducing the chances of become airborne.