Six days' worth of comfort.
The ride of tubulars is legend, and the Zipp Super-9 Carbon Track Disc Wheel is prepared to show you why. When combined with the smooth surface of a velodrome, you'll enjoy such a sure-footed, comfortable ride that, while you won't be in danger of falling asleep during your next six day, you'll also experience far less vibration-induced fatigue during long races. The Super-9 tub also drops almost 100 grams of weight compared to its clincher counterpart, meaning it spins up fast and won't hinder accelerations when you're trying to gain laps or respond to an attack.
Comfort and low weight don't mean the wheels are soft, though. Zipp also incorporates Kevlar thread in their carbon layup, which catches and disperses shock from impacts up to 350% better than carbon alone. This benefit is especially pronounced in the tire bed, where the rim is in greatest danger of taking damage due to unexpected impacts like, say, the calamitous cat that almost took out Cavendish on the track in Ghent.
While that comfort and durability stuff is certainly nothing to scoff at, you're ultimately here because of the aerodynamic benefits afforded by Zipp's wheels. The Super-9 carbon clincher still has a dimpling pattern that's specific to the 900, which helps smooth the air flow in order to minimize drag. Its Aerodynamic Boundary Layer Control (ABLC) carbon fiber skins are embossed with over 4900 golf ball-like dimples in five different sizes patterned to reduce turbulence. You get less drag in all wind angles, as well as less buffeting of the disc in crosswinds.
The hub used is Zipp's durable track hub, with internals manufactured using a high-voltage wire EDM technology. This specialized manufacturing process, usually reserved for avionics and Formula One gearboxes, lets Zipp machine 50% harder materials at tolerances 20 times greater than standard machining and heat treating. The result is a sub-200g hub that can handle the torque of a four-cylinder car engine.