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Niki Terpstra (Quick-Step Floors) suffered a catastrophic mechanical failure last weekend at Paris-Roubaix while riding in support of team leader Tom Boonen. In an episode that recalled George Hincapie’s broken steerer tube on the Mons-en-Pévèle secteur in 2006, Terpstra’s steerer tube broke unexpectedly on the Maing à Monchaux-sur-Écaillon sector, sending the 2014 Roubaix champion tumbling to the ground, ending his hopes for the day. Team sponsor Specialized has assumed full responsibility for the mechanical failure — but what exactly went wrong?
Specialized fielded sixteen riders on its new Roubaix frameset in this year’s Paris-Roubaix, and according to Specialized head of global marketing Mark Cote, fifteen of those riders opted for the stock Future Shock suspended front end (albeit with a team-only progressive spring rate that got stiffer as the fork moved through its travel).
Terpstra, however, wanted to go with a more traditional front end, with no suspension, that let him feel more of the road surface beneath him.
To accommodate that request, as first reported by Cycling Weekly, Specialized provided the team with a special aluminum plug to take the place of the standard Future Shock cartridge. According to Cote, that initial part was only intended to generate initial feedback for the concept.
“The first sample would have likely been fine under [regular] on-road conditions,” he told CyclingTips, “but it was a quick prototype to see how the bike felt.”
Once Terpstra gave his stamp of approval on the idea, Cote said that Specialized’s engineers then set about a full finite element analysis to develop a part that would more ably survive the rigors of Paris-Roubaix cobblestones. Specifically, the tube walls grew substantially thicker in the most highly stressed areas, and the shape also grew more sophisticated as compared to that comparatively roughly hewn prototype. Larger-diameter radii were also added where needed so as not to produce any dangerous stress concentrations where a crack might initiate.
“It was the same materials in both: 7075-T6 aluminum,” Cote explained. “But the product that was re-engineered had tube walls that were over 2mm thicker in the area with the highest stress, where the actual failure occurred.”
Unfortunately, a miscommunication between Specialized and the team allowed Terpstra to continue riding that initial prototype instead of the more finalized version he should have been using. Given those undersized tube walls — plus the fact that his fully rigid machine bore the full brunt of the cobbles as compared to other riders using the Future Shock suspension system — a crack formed at the base of that prototype plug and eventually propagated to the point where the tube could no longer take the pounding.
Cote was quick to stress that there were only issues with that initial prototype plug during the race; standard Future Shock cartridges weren’t affected. Even so, Cote acknowledges that there’s no telling how the race could have played out differently had Terpstra been able to carry on unencumbered with the part that should have been on his bike.
A former winner of the race, who had finished in the top 10 at Gent-Wevelgem and the Ronde van Vlaanderen in the lead-up to Roubaix, would likely have played a crucial role in the finale, and perhaps enabled Boonen to jump across to the winning trio of Greg Van Avermaet (BMC Racing), Sebastian Langeveld (Cannondale-Drapac), and Quick-Step Floors teammate Zdenek Stybar. Instead, Terpstra was out of the race well before the attacks started flying.
“We really did our best to go above and beyond,” Cote said, “and ultimately, due to poor communication, we just screwed up.”