Rui Costa was forced to switch to his road bike for the Tour de Romandie Prologue time trial after the chainring on his Cube time trial bike sheared off on the start ramp.
The Portuguese former World Road Race champion's chainring appeared to fall or shear off under his starting effort and was dangling off the chainset before Costa had even reached the bottom of the start ramp of the short 6.82km stage.
An Intermarché-Circus-Wanty team helper was on hand almost immediately but could only provide Costa with a spare road bike, not a second-time trial bike.
Costa was also visibly in pain after looking to have banged his knee on his time trial base bar after the chainring gave way. He finished last on the stage 4 minutes and 52 seconds down on stage winner Josef Cerny (Soudal-QuickStep) but appears to have survived the time cut.
Disaster for Rui Costa in Switzerland #TourdeRomandie pic.twitter.com/uOJtkN44uBApril 25, 2023
The Intermarché-Circus-Wanty team use Cube road and time trial bikes fitted with Shimano Dura-Ace groupsets and Rotor chainsets, the team appear to use the Rotor Aldhu chainset for road and time trial use.
The Aldhu chainset is a modular unit with carbon or alloy crank arms and an integrated power meter that can be set up in either 1x or 2x configurations with a splined spider that mounts directly to the arms. From the race footage, it appears Costa was using a 1x setup for the prologue with a Rotor Aero four-bolt chainring.
It's unclear exactly what caused the failure to occur. It's difficult to imagine something as important as chainring bolts being left undone by team mechanics. Chainring bolt threads usually have a thread lock compound applied and torque specs are clearly marked. Perhaps the bolts themselves or the mounting holes failed under Costa's effort. We will update this story if we hear more from the team or Costa himself on the failure.
