Fabio Jakobsen (Picnic-PostNL) suffered a heavy crash on stage 4 of the UAE Tour, in which his front tyre and foam insert were both ripped completely off his front rim.
The incident occurred with just under 30km on the flat stage, where the Dutchman was hoping to contest the sprint finish but ended up having to ride gingerly home with his kit ripped to shreds.
A spare bike was obviously needed, too, as the tyre and foam insert were both wrapped around the frame and no longer in contact with the wheel at all.
It is unclear initially what exactly caused the crash, which was not clearly captured by the television cameras. The peloton was strung out on a false flat on a wide road, and when the cameras caught up, Jakobsen was picking himself up off the ground along with Ethan Hayter, Daan Hoole, and Robbe Ghys.
Spokespeople for both the Picnic-PostNL team and their wheel supplier Ursus later told Cyclingnews that the cause of the incident was Jakobsen hitting a rock in the road.
"It was clarified that Fabio Jakobsen hit a rock while riding at speed, which impacted on both the tire and the rim. This caused the tire’s coming off the rim," read a statement from Ursus.
Jakobsen appeared to be using Ursus' Proxima R 60 Team Edition model. Interestingly, he was riding unbadged tyres in recent stages, which look to be a new version of a Vittoria Corsa Pro Speed, which has recently been released in a 30mm size, though this is unconfirmed.
The pairing of tyres and rims has been a hot topic in recent years in the wake of a number of blowouts on tubeless set-ups. Foam inserts are used to keep the tyre on the rim in the event of a catastrophic and sudden loss of pressure, and also allow riders to ride on the insert in a 'run-flat' scenario.
Hookless rims, whereby the inner rim has no retaining hook, relying on the outward air pressure and tight tolerances to keep the tyre on the rim, have attracted controversy over a perceived propensity to unseat certain tyres, depending on the relative widths of the rim and tyre.
Ursus' Proxima R 60 Team Edition is described as a 'mini-hook' rim profile, though from renderings on the brand's website it appears to not feature a discernible hook at all.
"The Proxima Team Edition features Ursus’ mini-hook system: the hook is effectively present, albeit shorter in size," Ursus told us. "So far, Ursus has never reported failures related to this system."
