The information originated from an email from the Intermarché-Circus-Wanty team to Rotor on the mechanical issue.
Upon making his initial starting effort down the Prologue start ramp Costa ripped out all four of his chainring bolts. The broken bolts were later found on the start podium.
It transpired the wrong chainring bolts were accidentally used which caused the mechanical. Shorter single chainring bolts had been used instead of the longer bolts needed to run a double chainset. Meaning the big chainring was not fully supported. Team mechanics have been instructed to double-check all bikes to ensure they have the correct bolts.
The image provided by Rotor shows the difference in depth between single and double chainset chainring bolts. Note the orange-coloured thread lock compound on the bolt threads (Image credit: Rotor)
It transpires that Costa was using a double chainset, but with the shorter chainring bolts designed for single chainrings fitted in error. The shorter bolts would have had minimal thread engagement which wouldn't have held up to Costa's starting effort, resulting in the bolt failure.
Cyclingnews has reached out to the team for comment but hasn't received a response at this time. We will update this story if we receive further clarification.
Costa's chainring mechanical forced him to dismount just after rolling off the Romandie prologue start ramp (Image credit: Eurosport/GCN)
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Tom joined the Cyclingnews team in late 2022 as a tech writer. Despite having a degree in English Literature he has spent his entire working life in the cycling industry in one form or another. He has over 10 years of experience as a qualified mechanic, with the last five years before joining Cyclingnews being spent running an independent workshop. This means he is just as happy tinkering away in the garage as he is out on the road bike, and he isn’t afraid to pull a bike apart or get hands-on with it when testing to really see what it’s made of.
He has ridden and raced bikes from an early age up to a national level on the road and track, and has ridden and competed in most disciplines. He has a keen eye for pro-team tech and enjoys spotting new or interesting components in the wild. During his time at Cyclingnews, Tom has already interviewed some of the sport's biggest names including Mathieu van der Poel, Tadej Pogačar and Alberto Contador. He's also covered various launches from brands such as Pinarello, Ridley, Specialized and more, tackled the Roubaix Challenge sportive aboard his own rim-brake Cannondale SuperSix Evo, tested over 20 aero helmets in the wind tunnel, and has created helpful in-depth buying advice relating to countless categories from torque wrenches to winter clothing.
