Zipp 303 NSW Carbon Clincher Road Wheelset

Where were you some six years ago this spring' We remember exactly where we were: glued to the couch on a Sunday morning with a sack full of fast food pommes frits and a six pack of Leffe Blonde, watching the ancestor of Zipp's 303 NSW Carbon Clincher Road Wheelset prove its mettle on the cobblestones of Flanders. We'd seen carbon rims on the stones before, and the results were typically disappointing, to say the least. But in 2010, the 303 platform proved that it's more than equal to the bullying of the stones, and the 303 NSW represents an update in every key category. It's more aerodynamic, brakes better, and is even more reliable than before. And that's just the rim. For the first time in its lifespan, the 303's new hubs are every bit as impressive as its rims. We admit that we haven't always associated Zipp with hub innovation, but the 303 NSW's Cognition rear hub may be the most exciting technology in factory wheels that we've seen since Zipp first introduced its bulging sidewalls. The freehub is centered on Zipp's Axial Clutch mechanism, which features two Metal Injection Molding MIM ratcheting rings one mated to the freehub body and one mated to the hub body. The two rings are machined like a ratchet, so they ramp off of each other while freewheeling but engage each other during pedal input. Compared to a standard pawl design, which actually resembles a drum brake, the Axial Clutch's MIM rings engage laterally to reduce friction while freewheeling, so coasting doesn't negate watts already spent. We're familiar with this model, as we've seen similar mechanisms on the designer hubs featured in top end custom builds for years now, but Zipp is the first to replace the usual tensioning agent, steel springs, with magnets. This substitution further reduces friction between the ratcheting rings, making for what may be the smoothest freewheel on any mass produced hub set. It's a design that we suspect will eventually be the norm, but once again Zipp is...