Wout Van Aert and Christophe Laporte, two of Jumbo Visma's favorite riders to win Paris-Roubaix, suffered unusual mechanical problems during the race. In two completely unrelated incidents, both riders' Shimano Dura-Ace 9100 series tubular rear wheels cracked and snapped in half.

The first accident occurred when Wout van Aert took on the infamous Arenberg Forest. Television cameras focused on the Belgian on teammate Timo Roosen's bike, for reasons that were initially unclear. However, roadside footage shared on Timo Roosen's Instagram account revealed that Van Aert's rear wheel broke in half and that a quick bike swap with Roosen allowed Van Aert to continue riding.

LaPorte's accident was elsewhere on the course, and roadside footage also shows the Frenchman surfing his bike after a wheel broke under him, forcing him to stop.

A spokesperson for Team Jumbo-Visma confirmed that both riders were attempting to ride with flat rear tires before their respective breakdowns occurred.

For reasons unknown, all of Jumbo-Visma's riders' Cervélo bikes were equipped with the older 9100 series Shimano Dura-Ace groupset. This is despite the fact that the team had obtained and was using a newer version of this groupset (R9200) and was also using a mix of the 12-speed R9200 groupset and the 11-speed R9100 chainset.

It is speculated that the reason for reverting to 11-speed was due to the higher frequency of chain dropouts when mixing 11- and 12-speed chainsets, or the logistical simplicity of having all riders on the same equipment, despite the race being very complicated for the team mechanics

As a result.

As a result, teams were forced to use older R9100 series Dura-Ace wheels as well. The reason for this is simpler: the freehubs on the new wheels are not backward compatible with 11-speed cassettes.

The wheels in question are tubular, the preferred tire interface technology for decades until the rise of tubeless tires. The tire they chose was a cottonwall Dugast (now owned by Vittoria) and was 30c wide.

Tubular tires have several advantages over tubeless and clincher tires. One advantage is the reduced weight of the wheel, but the biggest advantage is that the tire is glued to the rim, so that if the tire goes flat, it remains in place and the rider can continue riding, albeit a little more cautiously, until the team cars catch up.

This is a common practice in the World Tour and is considered safe on the flat roads of a typical bicycle race, but it apparently could not withstand the brutality of the Paris-Roubaix cobblestones. Repeatedly hitting angular stones on carbon rims protected only by a layer of uninflated rubber is, of course, not the wheel's intended use. Jumbo Bisma was unfortunately made painfully aware of this on two occasions.

As tubeless tires continue to rise, these incidents may be another nail in the coffin of tubular tires. Tubeless tires, by contrast, are self-sealing, eliminating the need for riders to stop at all, and can be run with foam inside to dampen sharp impacts. They are not without drawbacks, however. If the tire fails to seal, it will come off the rim, forcing the rider to stop immediately.

After all, there is no such thing as a perfect tire system, and riders know that continuing to ride with a flat tubular tire carries the risk of failure. But for riders, when they choose to stop on the shoulder, the cost is worth the risk.