Zipp redesigned the 303 from the ground up for the S model, and the result is a wheel that prioritizes real-world speed over wind tunnel metrics alone. The 45mm-deep rim uses a wider 25mm internal width that lets modern tires—28mm and above—assume their intended aerodynamic profile, creating a continuous shape from rim to rubber. This approach acknowledges that the tire is part of the aerodynamic equation, not just the wheel, and optimizes accordingly.

The Sawtooth dimple pattern across the rim's fairing surface manages airflow in ways smooth carbon cannot. These precisely engineered surface textures reduce drag and improve crosswind stability by controlling how air attaches to and releases from the rim. In gusty conditions or when trucks pass on open roads, the 303 S tracks predictably rather than getting pushed around—confidence that matters when you're descending or riding in a pack.

Hookless bead construction allows for a wider rim bed without adding material, keeping weight competitive while improving the tire-to-rim seal. The design requires tubeless-ready tires and works optimally with 28mm to 38mm widths, giving you latitude to run supple rubber at lower pressures for comfort without sacrificing the aero gains. Zipp rates the system for pressures up to 72.5 psi, which suits how most riders actually set up modern road tubeless.... Read More