Zipp 303 XPLR SW Rear Wheel The Zipp 303 XPLR SW Wheelset is the fastest gravel wheel Zipp has ever developed, featuring a mega-wide and deep rim that integrates seamlessly with gravel tyres. Unlike current gravel wheels, which are slightly modified versions of road wheels focusing on high stiffness and low weight, Zipp's design prioritises speed. Rolling resistance, vibration loss from rough surfaces, and wind are significant barriers to speed in gravel riding. To address these challenges, Zipp applied its Total System Efficiency design philosophy specifically for gravel. Speed-Focused Gravel Wheel: The 303 XPLR SW starts with the perfect gravel tyre and designs the wheel around it. Zipp's engineers analysed recent changes in gravel racing, leading to several vital conclusions. Aerodynamic Efficiency: Increasing gravel speeds highlight the importance of aerodynamic efficiency. Current gravel wheels perform poorly aerodynamically with gravel tyres. The 303 XPLR SW, designed as a seamless airfoil cross-section with gravel tyres, provides a 5-watt aerodynamic advantage over leading competitors. Low Tyre Pressures: Essential for unlocking speed on gravel but current rim designs fail to support lateral cornering loads at low pressures. The 303 XPLR SW’s wide tyre bed increases tyre stance, allowing lower pressures without squirming, decreasing vibration loss while maintaining control in corners and traction while climbing. The rim edge is 77% thicker than previous models, reducing pinch flats and potential damage when tyres bottom out. Rim Depth: Contrary to conventional thinking that shallow rims are best for gravel, the 54mm deep rim of the 303 XPLR SW creates an effective aerodynamic complement for large gravel tyres at high speeds (35kph+). The deep rim creates the perfect aspect ratio for aerodynamic efficiency with a 40mm gravel tyre at race speeds. Tyre Compatibility: Optimised for use with Goodyear XPLR Slick and Goodyear XPLR Inter tyres, both designed in partnership with Zipp. Tyre Widths: Typical widths for gravel racing range from 38-50mm. The 303 XPLR SW wheelset represents a groundbreaking approach to gravel racing, focusing on integrating tyre and wheel design to deliver unparalleled speed, comfort, and performance.