Carbon fiber is composed of extremely thin, bonded fiber made of carbon atoms. Thousands of carbon fibers are bundled together into cloth-like sheets. The sheets are combined with plastic resin. The sheets are placed into a mold with the fibers oriented in specific directions to create the desired characteristics of strength, stiffness or flexibility for the completed rim. Carbon fiber is used in wheels because of the high strength-to-weight ratio, low weight and the ability to mold the sheets into aerodynamic shapes. The subject of intense study in cycling, aerodynamics is the air flow over and around your wheels, bike and body as you ride. The goal of aerodynamics is to reduce the wind resistance called drag on your equipment, so the rider slices through the air and goes faster. At slow speeds, there is smooth air flow called laminar flow. As speed increases, the laminar flow turns to turbulent flow. There is a “sweet spot,” the point of reduced drag, when the air begins to tumble over and across the wheel surfaces in turbulent flow. The key to top carbon fiber wheel design is to produce rim shapes that optimize, capture and maintain the aerodynamic sweet spot for each rim depth.
Bill Shook started the engineering process on our carbon fiber rims from the inside, dictating the direction and lay up of the fibers to form stronger internal spoke beds for structural integrity and stiffness. He then moved to the outside of each wheel, designing unique features for aerodynamic performance to achieve the “sweet spot”. Carbon 38, Carbon 44 and Carbon 50 are the most challenging shapes because of their minimal surface area. Bill designed a gentle curved shape down to the spoke bed to minimizing drag by bringing the air flow back together without turbulence. Carbon 58 tubulars and clinchers have a recurve shape under the brake track. The recurve shape creates air pressure fluctuations causing a ripple effect to induce turbulent air flow to reduce drag at higher speeds. Carbon 85 tubulars are a semi disk shape with no spokes near the leading edge of the wheel. Bill designed the large, smooth carbon surface bringing air back together reducing cavitation behind the spokes. Carbon TT Disk is the ultimate in aerodynamics with lenticular skins to sustain the sweet spot for maximized power output.