The UCI has a new weapon in the war on tyres that are a little bit too wide

The Union Cycliste Internationale (UCI) has introduced a new handheld, 3D-printed tool to enforce equipment regulations concerning tyre sizes in professional road cycling. Spotted at the start of the men’s Paris-Roubaix race, this device is designed to quickly check whether riders’ tyres comply with the maximum allowed dimensions. While road racing does not impose a direct limit on tyre width, there is a restriction on the overall diameter of the wheel-tyre combination, which effectively caps the tyre height and width to around 39mm, depending on the rim width. The tool appears to be a practical solution to the challenge of measuring tyre diameters efficiently across multiple teams at large events. Given that all road wheels conform to a standard rim diameter of 622mm, the total diameter is influenced primarily by tyre height. By slotting the device over the tyre, commissaires can rapidly assess compliance without resorting to time-consuming measurements of the full wheel-tyre system. However, it remains unclear whether the device measures the actual tyre height or uses a nominal width as a proxy for legality. Observations from Cyclingnews’ technical reporter Will Jones suggest that the checks were somewhat cursory, with commissaires simply placing the tool on the tyre and moving on if it did not get stuck. This implies that the device serves as a quick pass/fail gauge rather than a precise measuring instrument. Paris-Roubaix, known for its rough cobbled terrain, is one of the few races where teams push tyre sizes to the limit, often opting for wider tyres around 35mm to improve comfort and durability, as seen on Tadej Pogačar’s bike ahead of the race. The introduction of this tool reflects the UCI’s ongoing efforts to maintain fairness and safety in equipment standards without disrupting the flow of race preparations. While it is unlikely to be deployed widely across the road racing calendar, its use at high-profile events like Paris-Roubaix highlights the delicate balance between innovation and regulation in professional cycling. Future developments may see refinements in how tyre compliance is monitored, ensuring that teams adhere to rules while continuing to pursue technological advantages.