Jayco-AlUla rider, Amaury Capiot, miraculously avoided injury despite ending up with a rear wheel in tatters thanks to the cobbled roads in yesterday’s Omloop Het Nieuwsblad.
Although it’s not clear exactly what caused the failure, Capiot was spotted by photographer, Tim de Waele, walking along the race course with his Cadex rear wheel in tatters, trying to reach a team car for a spare bike.
Not only was Capiot’s tyre completely separated from the rim, but the entire rim and all of the spokes were separated from the hub – which remained fixed in the rear dropouts of his Giant Propel Advanced SL via the thru-axle.
Despite the state of his rear wheel, Capiot thankfully appeared unhurt by the failure and went on to finish the race almost ten minutes behind race winner Mathieu van der Poel.
What we know so far
Capiot’s rear wheel failure is the latest in a string of high-profile incidents in pro cycling involving tyres separating from rims.
Unfortunately, the inciting incident appears to have happened off the race's video feed, meaning we’re unable to analyse exactly what happened to cause such a complete failure.
According to Cyclingnews, a team spokesperson claimed the failure occurred as “the result of riding for too long on the cobbles with a flat tyre after puncturing”.
Zooming in on the photos, we can indeed see the rim is broken, which would help explain why Capiot’s Cadex Aero Cotton tyre and Vittoria Air-Liner tyre inserts have dismounted the Cadex Ultra 50 rim.
This doesn’t provide a full explanation of why the rim and spokes have separated from the hub, however.
Although we can’t be certain, it appears a number of the wheel’s carbon spokes have failed – as there seems to be some missing from the lower half of the wheel.
Perhaps as a result of these failures, the rest of the intact spokes may have lost tension and were therefore no longer securely held in the hub.
Many of the remaining spokes appear intact, so it doens't seem to be the case that all of the carbon spokes have simply shorn off the hub.
Are hookless rims to blame?
In recent years we’ve seen a number of professional cyclists crashing or standing by the side of the road because of tubeless tyres dismounting rims.
Thomas De Gendt suffered a high-speed crash at the 2024 UAE Tour as a result of a rock strike that damaged his Zipp rim and caused the tyre to dismount.
More recently, Fabio Jackobsen suffered a similar fate at this year’s UAE Tour, and we’ve seen a number of examples of wheel failures at Paris-Roubaix – the toughest cobbled classic on the pro cycling calendar.
Many have pointed the finger of blame at ‘hookless’ or ‘Tubeless Straight Side’ rims, claiming their lack of tyre bead hooks (that traditional ‘Tubeless Crochet’ rims have) increases the chances of tyre blow-offs.
The brands involved dispute this, however. Following De Gent’s 2024 crash, both Zipp and Vittoria (De Gendt’s wheel and tyre sponsors) claimed the failure was due to his rim breaking due to a rock strike, and was "unrelated" to the fact the rims were hookless.
De Gendt was also using 28mm Vittoria tyres on a Zipp 303 NSW rim with a 25mm internal width. This was a combination approved by both Vittoria and Zipp at the time, but wasn't according to the latest ISO standards, which stated that 29mm was the minimum tyre size for 25mm-wide rims.
In Jakobsen’s case, he was riding so-called ‘mini-hook’ rims from Picnic PostNL’s team sponsor, Ursus.
Despite ‘mini-hook’ having gained prominence as a marketing term in recent years, it isn’t actually a new rim standard, as defined by the European Tyre and Rim Technical Organisation (ETRTO) or the International Organization for Standardization (ISO).
Instead, these are Tubeless Crochet, or ‘hooked’ rims that meet or go just beyond the minimum requirements for that standard – meaning they must have tyre bead hooks at least 0.5mm in depth.
In that case, then, hookless rims were not to blame.
In Capiot’s case, his Cadex Ultra 50 rims were hookless, but as far as we can tell his setup fell well within the approved standards. Giant and Cadex have also previously detailed that their hookless testing goes above and beyond the required standards.
Given Omloop is a race featuring many cobbled sectors, it’s easy to imagine him striking a particularly sharp cobble at high speed, and catastrophically damaging his rim and some of the spokes.
It may be possible Capiot's tyre would have dismounted the rim under such duress even if he'd been on hooked / Tubeless Crochet rims.
As mentioned earlier, though, this doesn’t explain why the rest of the undamaged spokes were able to completely detach from the hub.
Does Cadex’s Ultra 50 hub design simply not have sufficient ‘redundancy’ built in to guard against this type of failure?
We’ve contacted Giant / Cadex and will update this article when we receive a response.
