Expanding greatly on its heritage of conquering the Spring Classics, 303S wheel maintains its ideal-for-every-terrain 45mm rim depth but adds a significantly wider internal width to provide greater performance and ride quality in almost every measurable way. Road bikes are more versatile than ever, no matter the road surface, but just as fast as before. The 303 S offers a redesigned rim profile and design to optimize rider performance on this new breed of bike. This wheel is tubeless for disc-brake bikes, allowing the ability to run wide tires at lower pressures for race-ready speed on or off the pavement.
The 303 S is among the lightest wheel, optimized for top aero performance with a 28mm tire but capable of handling gravel tires up to 50mm wide. The key innovation is in the 303 S’s rim design. Its 45mm rim depth is the same as its predecessor, the 302 Disc brake. But its external rim width is 2mm wider, at 27mm, and its tire bed is a full 7mm wider, at 23mm internal width. That rim platform is designed to be the fastest with a 28mm tire. The wide rim optimizes tire profile to allow lower tire pressure. That helps to reduce rolling resistance and provides a more compliant ride. The result of all this is a 10 watt savings vs. a top peer wheel in total power required to ride 40kph on a flat road with a 28mm tire, according to internal Zipp testing. This groundbreaking wheel also features updated cosmetics, setting the rider apart from the pack, and comes at an attractive price.
 
Features
Zipp graphics and cosmetic identity that scream speed. 
Fastest with 28 mm, fits wide gravel tires as well. 
Wide rims optimize tire profile to allow lower tire pressure, especially with tubeless. The result is a larger contact patch for increase grip for confident cornering, descending, and handling in wet conditions. 
Lower tire pressures and larger volume provides a compliant ride with fewer vibrations. 
Significant watt savings when running larger tires at lower pressure. 
Wide hookless rims create a seamless transition to the tire, reducing drag. 
76 / 176 DB hubs with center locking interface. 
XDR driver body option. 
Max tyre ressure: 72.5 psi (5 bar) 
Disc rotor standard: Center Lock 
Front hub: 12x100 mm. 
Rear hub: 12x142 mm.