The resulting sheets of carbon fiber are trimmed to size with a precision cutting machine. The pieces are then layered and shaped into bicycle rims using a mold. Rim manufacturers can use modern technology such as computer modeling and 3D printed molds to shape wheels with incredible precision.
Next, the carbon fiber sheets and mold are heated up in an oven. The wheels are heated in a special heating cycle called a ramp cycle. The heat starts at a low temperature and ramps up over time then cools off. The temperature and heating time are precisely controlled. This process melts and combines the layers into a single piece and hardens the wheels. When the wheels come out of the oven, they are finished.
Not all carbon fiber wheels are equal. There is quite a bit of variation in the way that carbon wheels are built and the way the carbon fiber itself is made. For example, manufacturers can vary the type of resin used, the direction of the fibers, the weave of the fibers, the density and types of fibers used, the grade of carbon fiber, the thickness of the layers, the number of filaments per tow, the way the material is heated and molded, etc.
All of these variations play a role in the stiffness, weight, and durability of the finished wheels. This can affect the wheel’s weight, the bike’s handling, ride characteristics, and comfort. Manufacturers can opti
characteristics, and comfort. Manufacturers can optimize carbon wheels for different types of riding. For example, a road wheel could be made stiffer and an off-road wheel could be made flexible
