When Zipp got its start a little over a century ago, the company was nearly synonymous with disc wheels. After all, a wheel with a wind cheating disc profile was the first product Zipp created, and it's how the company made its name in a world that had never seen disc wheels before. Today, Zipp still strives to create faster wheels in a market that is becoming more crowded every year by using extensive wind tunnel testing, pro feedback from the likes of the current world time trial champion, and a host of proprietary technology. Designed to be paired with an 808 or 404 Firecrest carbon clincher up front, the Super 9 Disc Rear Carbon Clincher carries Zipp's aerodynamic torch admirably as an incredibly efficient choice for your next triathlon or time trial. Through extensive wind tunnel testing, Zipp's engineers came to the somewhat controversial conclusion that clinchers are more aerodynamically efficient than tubulars. The engineers made this assertion by focusing on the well established fact that the transition from the tire surface to the rim surface is highly instrumental in allowing airflow to stay attached to the wheel and creating less drag. As Zipp puts it, this transition area could work the most efficiently with a clincher design because a clincher's brake track can be molded to more closely follow the contour of the tire, tipping inward slightly rather than remaining completely parallel like a tubular would. This keeps the clincher tucked down into the relatively wide, 26. 42mm tire bed, eliminating any light bulb effect and increasing air volume in the tire for a lower chance of pinch flatting. The Super 9 carbon clincher still features the dimpling pattern that's found on the 900 and the Firecrest models, which effectively smooths air flow in order to minimize drag. Zipp calls this its Aerodynamic Boundary Layer Control ABLC. Essentially, this is a treatment to the carbon fiber, where the surface is embossed with over 4900 golf ball like dimples...