Firecrest
Firecrest technology was developed from Zipp's earlier “toroidal” rim shapes. These were designed with a bulge in the rim cross-section to reduce turbulence behind the tire at the leading edge of the wheel. Firecrest essentially inverts this shape, placing the leading edge of the airfoil along the interior of the rim (towards the hub). As a result, Zipp claims that Firecrest rims show improved aerodynamic performance at all points around the wheel, combined with improved stability in crosswinds. A product review on the Cyclingnews website reported, “The Firecrest aero profile is noticeably fast at cruising speed” and that a Firecrest wheelset “offers handling stability in crosswinds unmatched by other aero wheels we've used.”
NSW
Zipp NSW wheels feature the company's most advanced technologies and is short for "Nest Speed Weaponry" a reference to the company's advanced R&D office known as "The Nest". For example, the 82mm deep Zipp 808 NSW offers a claimed improvement in crosswind stability and a revised brake track for reduced stopping distances and improved all weather performance compared to Zipp's 808 Firecrest wheels. NSW wheels also featured the company's new “Cognition” hubset. The rear Cognition hub features what Zipp terms an “axial clutch” to disengage the ratcheting mechanism inside the freehub when coasting in order to reduce internal hub drag.