Zipp 404 Firestrike Tubular Wheel - Rear. The Zipp Firecrest wheels were a revolution in wheel design, and have had a profound influence on the entire wheel industry since. They were the first to realize that a wider wheel is a more aerodynamic wheel, since wind yaw angles can have as big of, if not a bigger, impact on aerodynamics than head on air pressure. The result of this discovery was the Firecrest rim shape, which was wider than just about any other wheel at the time, and has continued to be a benchmark in performance and durability. So when Zipp announced that they were introducing the Firestrike wheel late last year, most people asked what could they possibly have improved? The answered turned out to be a bunch of things. The biggest advance though is the braking performance. Carbon wheels have come a long way since the early days, but traditionally they still lag behind aluminum rims--especially in the wet. The new Zipp Showstopper brake track technology applies a molded brake track pattern and introduces silicon carbide into the surface for wet weather braking performance that is easily on par with aluminum braking surfaces. With this innovation, Zipp singlehandedly leaped frogged the competition again, by creating a wheel that is not only fast, but can slow down quickly as well. The other big advance is the Carbon Shield technology, with a new ply sequence of unidirectional carbon, as well a new mold-tool design and process to create a stronger and lighter rim than ever before. The new technology means that the new Firestrike is even tougher and more durable than the already venerable Firecrest rims, a fact verified by the pro teams over the brutal cobbles of le Carrefour de l'Arbre, once of the worst sections of Paris-Roubaix, where the rims withstood the worst abuse imaginable, without any damage, chipping or cracking. With Carbon Shield and Showstoppertechnology, the Firestrike takes carbon wheels out of the race day only and into the everyday realm for any rider. Other updates include a new ImPress graphic treatment that reduces weight and looks better than traditional decals, CeramicSpeed bearings with incredibly low rolling resistance and a longer wear life, and an all-new ABLC (aerodynamic boundary layer) control system that smooths airflow more precisely for better stability and control and handling, even in windy conditions. This, combined with the new CFD (computation fluid dynamics) modeling results in a 34% reduction in side force, while maintaining excellent, race-ready performance.