You might need a microscope to understand the intricacies of the 404 Firecrest Tubular, but you certainly don't need one to grasp the magnitude of its records. From L'Alp d'Huez to Kona, it's nearly impossible to find another wheel with such a storied career. However, the best just got better with the 404's adaptation of Zipp's 177 rear hub. The future is here.
The 404 maintains a rim depth of 58.0mm and a maximum width of 26.53mm in the front and 27.07mm in the rear. The Zipp 77/177 creates a more stable structure, and offers greater vertical and lateral compliance with increased control, comfort, and rigidity. While the 404 benefits from these welcomed additions, to achieve the Zipp-standard of strength and rigidity, the 404 utilizes unidirectional fibers to handle the tensile and comprehensive loading within the rim, and woven fibers in the spoke-hole areas. A woven silica-ceramic fabric and a woven carbon fabric encapsulate the braking and tire-mounting surfaces. The combination of fiber patterns creates a high stiffness-to-weight ratio without stacking up the grams.
The wheels still receive an 18/24 Sapim X-Ray spoke configuration, but on the rear wheel Zipp moved from a radial non-drive side and two-cross lacing drive side pattern to its new "virtual three cross" lacing configuration on both sides. Zipp uses the word "virtual" here to describe the manner in which one spoke doesn't actually contact the other two spokes it crosses. The result is a stiffer overall construction that more effectively transfers power directly to the rear wheel, which is crucial for those out-of-the-saddle sprints and climbs.
The Zipp 404 Firecrest Carbon Tubular Road Wheel is available in the color Black with either Black labels. Every wheel is hand-built in the USA, compatible with 10 or 11-speed cassettes. Please note that Zipp's maximum recommended rider weight is 250lbs.