LONDON - Mercedes say Lewis Hamilton's unusually poor US Grand Prix qualifying last weekend was due to a protective device on the steering wheel being accidentally knocked off, affecting the car's performance.
The Briton qualified only fifth fastest in Austin, while Finnish team mate Valtteri Bottas took pole position, before finishing the race in second place to secure his sixth world championship.
Hamilton had qualified on pole in Austin for the previous three years and had started on the front row there in every race since 2014.
"During the course of the lap, underneath his right hand, there's a little rotary and that rotary adjusts the engine braking," said Mercedes' strategy head James Vowles in a race debrief.
"Normally it has a guard on it, and what happened is the guard had been accidentally knocked off and as he went through the lap and every time he turned the steering wheel, he accidentally changed the engine braking and that caused him to lose performance towards the end of the lap.