The Sub-9 Disc Gives You Speed!
Allright, we'll admit it, when we first heard Zipp's claim of "negative drag" being created by their new Sub-9 disc our first reaction was a good laugh. Instantly we thought of humorous oxymorons like "giant shrimp," "no truth," "sharp cookie," "serious comedy," and "random order." Our second reaction was, "What a bunch of marketing hype." As usual, strong reactions are symptomatic of a lack of understanding, and boy did we have a strong reaction and a serious lack of understanding.
In fact, Zipp's Sub-9 disc not only dramatically reduces drag, in the right conditions it actually has a sail-like effect which helps propel the rider. In short, the Sub-9 creates negative drag by actually working for you, not against you.
The same principle working to create lift on an airplane wing is at work with the new Sub-9. Depending on the angle of wind resistance coming towards a rider in motion (so called "yaw") the Sub-9 gives the rider forward momentum by decreasing wind resitance up to 80 grams. At 15 degrees of yaw (which studies show happens in 70% of all conditions) this translates to a whopping 1/5th of a pound of decreased drag. When you consider that in time trials and triathlons a massive 75% to 90% of your energy is consumed by overcoming wind resistance a 1/5th of a pound translates to a stunning 11 watts of added power! Add to the mix Zipp's Tangente tubular tires for a total overall gain of 16 additional watts. That's an improvement of 5% for a rider generating 320 watts. That translates to a 1.5 mph gain at an average speed of 27 mph, or a mind-blowing 2.5 minutes over 40 kilometers!
Zipp's Sub-9 is not only faster, it rides better and handles better, too. The bulging shape of Zipp's carbon bridge construction allows for a more compliant and safer handling disc which means that a rider in competitive stress can relax a little, fatigue more slowly, and have more punch left for the final kilometers.