 The appeal of the 404 stems from its aerodynamics and a low rim weight (resulting in a low moment of inertia) which make it a versatile wheel for flat and hilly terrain.In 2011 Zipp released a new line of its long-awaited carbon clincher wheelsets.The 303, 404, and 808 Firecrest carbon clinchers were designed to provide decreased aerodynamic drag and increased stability in crosswinds as well as improved braking performance on long descents.