Official Tyre of Ironman. Schwalbe has developed a tyre specifically for the sport of triathlon. Ambitious triathletes today use special time trial bikes and aerodynamically optimized wheels. The new Schwalbe Ironman is optimized for this set-up. In the optional tubeless version, it is particularly fast and puncture resistant. The name Ironman is a trademark of World Triathlon Corporation (WTC) and is used under the license of Schwalbe.
OneStar Compound
Aerodynamics: Space is usually limited for aerodynamically optimized wheels on time trial bikes. Therefore, Schwalbe chose a narrower 22mm tyre width than the usual 23mm. Because modern aero wheels today are more bulbous and have wider rim widths than classic wheels, this makes the tyres, in practice, become slightly wider.
Wind Tunnel: In complex wind tunnel tests, Schwalbe determined the tyre width that produces the least aerodynamic drag for the entire wheel system. The 22mm tyre width was by far the best. The bulbous aero rims resulted in both the common 23mm tyre width as well as very narrow 20mm and very wide tyres in 25mm width having a measurable increase in aerodynamic drag.