Helio Castroneves Wins Indianapolis 500 for a Fourth Time

“I knew I had the race to win, but the whole race was so intense,” Castroneves said. “From the drop of the green flag, it was a fight.”

The race’s first plot twist came during the initial round of pit stops, starting at Lap 30. Half the field had made their regular stops, while the other half tried to stretch their fuel economy to the limit. That strategy backfired when Stefan Wilson crashed on pit road, closing it. Those still on the course, like the former Indianapolis 500 champions Scott Dixon, Alexander Rossi, Tony Kanaan, Pagenaud and others, were unable to make their planned pit stops — and ran out of fuel. Before they could get restarted and refueled, they each lost more than a lap, knocking some prerace favorites, including the pole-winner Dixon, out of contention.

In the next segment, the sport’s vaunted youth movement, which has turned IndyCar’s entrenched order on its head so far this season, established itself at the front of the field: the Indiana native Conor Daly, 29, moved to the lead ahead of VeeKay, 20, followed by O’Ward, 22, Herta, 21, and Palou, 24.

Despite their raw speed, however, another key factor, fuel mileage, was starting to come into play. Veterans like the 2014 winner, Ryan Hunter-Reay; Castroneves; the two-time winner Takuma Sato; and Graham Rahal were wisely stretching an extra lap or two, or more, out of every tank. Thinking of the end of the race, they hoped to make one fewer fuel stop than the rabbits up front. That would be a savings of as much as three-quarters of a lap.

Generally speaking, it seemed the drivers powered by Honda engines were getting better mileage than the Chevrolet runners. But at the 300-mile mark, fuel mileage was taken somewhat out of the equation when Rahal, the fuel economy champion to that point, lost his left rear wheel after a pit stop, causing him to crash; Daly clobbered the loose wheel. That brought out a yellow caution flag that bunched the field, jumbled the order and neutralized the best fuel strategies.

“We had ’em,” a dejected Rahal said afterward. “I mean, we had it figured out.”

His teammate Sato, however, was still on the same strategy and hopeful of benefiting from it. He was leading when he pitted on Lap 158, meaning he would need only a short splash-and-go fuel stop around Lap 190 to go for the win.

Other fuel mileage hopefuls were Dixon, who managed to unlap himself during Rahal’s yellow, and Josef Newgarden.