Thomas De Gendt’s Crash Highlights Safety Concerns with Hookless Road Wheel Systems
Belgian cyclist Thomas De Gendt experienced a serious crash during stage five of the UAE Tour, raising concerns about the safety of hookless road wheel systems. De Gendt, who is in his final professional season, fell mid-stage and suffered cuts and bruises. The cause of the crash appears to be a mismatch between the tire and rim dimensions, specifically a hookless tire and rim combination. This incident sheds light on a major issue that riders using hookless road wheel systems should be aware of.
The crash occurred on a wide, smooth highway, with no debris or potholes in sight. It is unlikely that De Gendt hit something on the road. Instead, it is probable that the mismatch between the tire and rim caused the tire to blow off suddenly. The Lotto-Dstny team, using Zipp wheels and Vittoria tires, was not compliant with ISO standards regarding tire-rim compatibility. The 28 mm tire De Gendt was using is too narrow for the 25 mm internal rim width on the Zipp 353 NSW rim.
The updated ISO standards mandate that a 622x25TSS rim should be paired with a 622×29 TSS (hookless) tire. The pressure limit for hookless tires should not exceed 72 PSI / 4.9 bar, and this limit decreases as the tire width increases. It is possible that De Gendt’s crash was caused or exacerbated by not adhering to these standards.
The issue of mismatched tire and rim combinations is not limited to De Gendt’s case. The UCI has highlighted these mismatches to teams and plans to crack down on non-compliant combinations. Confusion in the hookless compatibility space and a lack of understanding among riders contribute to these mismatches.
The focus on tire width and the promise of increased comfort, grip, and decreased rolling resistance has overshadowed the importance of considering the internal rim width when choosing tires. ISO standards provide specific dimensions for tire and rim compatibility, and mounting a tire on a rim with a wider internal dimension can result in the tire expanding beyond its design specifications. This can lead to the tire riding up the rim sidewall and potentially exploding off the rim.
While hookless road wheel systems are unlikely to disappear, it is crucial to use reputable manufacturers and adhere to correct tire pressures. The rollout of the hookless standard in road cycling raises concerns about varying pressure limits, home pump gauge accuracy, and the safety of some rims that do not comply with required dimensions. There is a lack of understanding in the market, and riders are responsible for knowing complex compatibility factors.
To address these issues, there needs to be a central compendium of information on hookless safety and a shift in focus from tire width to compatibility. Riders should consider the specific requirements of their rims when choosing tires. The obsession with wider tires should not overshadow the importance of compatibility for safety.
In conclusion, Thomas De Gendt’s crash highlights the safety concerns associated with hookless road wheel systems. Mismatched tire and rim combinations can lead to accidents, and it is crucial for riders to adhere to ISO standards and prioritize compatibility over performance. The industry and riders need to be more informed about hookless safety to prevent future incidents.
