This wheel is optimized for 25mm tubeless tires for all out speed. The 454 NSW features Zipp’s most advanced technologies. Its undulating 58mm Sawtooth™ rim shape with Hyperfoils™ is our most aerodynamic and stable wheel. The 454 NSW features Zipp’s Total System Efficiency™ (TSE™), our approach at combatting the biggest enemies of speed: wind resistance, gravity, rolling resistance, and vibration losses. And gravity? The 454 NSW Tubeless Disc brake is roughly a pound (more than 400 grams) lighter than its predecessor! Zipp’s use of hookless (straight side) rims in the 454 NSW is integral to Making You Faster. With hookless, the transition between the tire and the rim is more seamless and aero. Zipp’s hookless rims have more efficient resin distribution, which means lighter, stronger wheels. At the center of the 454 NSW is the Cognition V2 Hubset re-engineered with an updated Axial Clutch V2™ mechanism for quicker engagement, lower friction, and improved durability.