Pascal Vasselon, Toyota Gazoo Racing Europe technical director, explained that the Japanese driver who shared the second-placed GR010 HYBRID Le Mans Hypercar with Sebastien Buemi and Brendon Hartley was caught out by a rearward brake balance setting at the tight Arnage right-hander.
This had not been communicated to Hirakawa when he took over from Hartley for the run to the chequered flag and attempted to close down a gap of approximately 15s to the winning Ferrari 499P LMH driven by Antonio Giovinazzi, James Calado and Alessandro Pier Guidi.
“The brake balance on that corner was really rearward,” said Vasselon.
“The drivers manipulate the brake balance they want corner by corner during their runs and Brendon gave Ryo a few indications of what he had done [at the driver change], but this one was missed.
“The information did not pass to him 100% in the few moments [at the pitstop] to be careful at this corner.”
Hirakawa lost the car under braking for Arnage three laps after taking over the car early in the penultimate hour of last month’s centenary running of the Le Mans enduro.
He hit the barrier front and rear on the entry to the corner, the resulting in two minutes lost to body repairs in the pits.
Speaking about the spin, Hirakawa said: “The mistake at Le Mans was painful, but we’ve been investigating, and we found a small thing, so actually I have more confidence in myself now.”
The time loss effectively drew a line under Toyota’s bid for a sixth consecutive victory at the blue riband round of the World Endurance Championship.
Vasselon stressed that no blame was apportioned to Hirakawa for the accident within the Toyota camp because the driver was told “to take maximum risk” in the pursuit of the Ferrari.
Hartley had been able to close the gap to 9s prior to the stops at a stage of the race when the Toyota appeared to have a slender pace advantage over the Ferrari.
“The circumstance was that he knew we were not interested in a comfortable second,” said Vasselon.
“That means there can be no complaint because that was a moment where we could win or lose the race.
“It was a mistake, but it was a mistake caused by wanting to win the race and not being interested in securing second.”
The eventual margin of victory between the Ferrari and the Toyota was 1m21.7s after Alessandro Pier Guidi lost approximately 30s in the final hour when he had to undertake a full electrical reset in the pits.
Additional reporting by Jamie Klein
