Boonen stopped with a mechanical problem on the Taaienberg with just 38km to race. His chain had come off and then got stuck between his inner chainring and the frame. The team scrabbled to get Boonen riding again, but the three-time winner - riding his last Tour of Flanders - was unable to ride himself back in to contention at such a crucial stage of the race.
On Wednesday, ahead of Scheldeprijs (opens in new tab) race, Boonen said; "the error was Shimano's. They had the wrong chainring."
"Normally we always ride with 53-39 rings, but Shimano used a 42 ring. That only works well in combination with a 54 or 55 outer ring. With an outer ring of 53, it can go wrong. And that was the case in the Tour of Flanders. In Paris-Roubaix it cannot happen again."
Boonen did not explain why Quick-Step's mechanics would have used these rings, since they mount his components and not Shimano, or why he would have been given a gearing ratio that he didn't request.
When Cycling Weekly contacted Shimano for a comment, the Japanese manufacturer suggested we speak with the Belgian WorldTour team regarding the matter. On Thursday, Boonen and the team met the press in a pre-Roubaix conference and at the same time, posted a statement on Facebook (opens in new tab).
Quick-Step issue apology
"Quick-Step Floors would like to underline that Tom Boonen's statement on his mechanical mishap at last Sunday's Ronde van Vlaanderen does not reflect reality. It was a consequence of the team's internal mis-communication," read the statement.
"Quick-Step Floors takes full responsibility for what happened and would like to apologise to Shimano for any comments made contrary to this in recent days."
Watch: Tour of Flanders highlights
Boonen was in the group with Peter Sagan (Bora-Hansgrohe) and Greg Van Avermaet (BMC Racing) when the mechanical happened. As he stood at the side of the road waiting for his team car, Sagan attacked and pushed clear with a small group in pursuit of eventual winner Philippe Gilbert.
"It's over, we don't have to talk about it," Boonen added. "Guys crashing, guys having mechanicals... It's a bike race, stuff happens.
"I see Kristoff finished fifth, and he wasn't on his best Flanders shape all day long, so I would have probably sprinted for fifth in the worst possible scenario, otherwise maybe for second. It doesn't matter, it happened, the race is over."
Boonen will use a 46-tooth inner chainring at Paris-Roubaix this Sunday. His final race.
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