Trek’s engineers set out to achieve the aero performance of a high aspect ratio within a compact, light profile that would be stiff, stable, and comply with UCI regulations. Veteran engineer Doug Cusack teamed up with new addition Paul Harder to investigate platforms for a cycling-specific airfoil. As Paul explains, “at the time, bicycle airfoils (industry-wide) were being designed using an old system for defining airplane wing airfoils. I saw this as a major disconnect and decided to study airfoils as they truly apply to bicycles as my first “personal” R&D project.” In order to test as many designs as possible, the team created a new approach to computational fluid dynamics (CFD) that acts as a virtual wind tunnel capable of testing 3D drawings. This more efficient approach allowed Trek to test more than eighty different shapes, something that would have never been possible in the wind tunnel. Doug had a hunch that truncating an airfoil could lead to a breakthrough in aerodynamic efficiency, and the CFD results the team saw with such designs exhibited unprecedented results. KVF was born. The new design solved a fundamental problem with previous platforms. Bike airfoils have very high curvature compared to a more stretched out airplane wing or stabilizer type of airfoil, and bikes also experience much higher yaw, or a larger angle between apparent wind (often inconsistent and coming from the side) and the direction of bicycle motion. The larger this angle is, the more unwanted lateral movement the bike will experience. As a result, air has a very difficult time staying attached to the airfoil wall and tends to separate, causing large amounts of drag and reduced stability. The truncated design of KVF solves this curvature problem by using the portion of a high aspect ratio that works the hardest, (the front), and doing away with the pointed rear that is less important in cycling-specific applications. Winds flow around the front of the foil like a traditional design, and stay on this trajectory because truncating the shape reduces its curvature. As yaw and crosswinds increase, so does the performance advantage of KVF.