Impact of Disc Wheel Geometry on Aerodynamic Performance: A Computational Fluid Dynamics Investigation

Aerodynamic drag is the main resistive force in cycling at high speeds and on flat terrain, so reducing it is critical to improving cyclist performance. Aerodynamic comparisons have been made in the past between different types of wheels, and disk wheels were often the best performers. However, to the best of our knowledge, there are no studies in the available literature on how modifications to the disk wheel geometry can improve its performance. Therefore, this paper studies and compares the aerodynamics of disk wheels with flat side disks and with curved side disks (lenticular). Moreover, semilenticular front wheels with an asymmetrical shape are introduced. All but one of the simulated (semi-)lenticular wheels perform better than the flat disk wheels at all yaw angles, e.g., the maximum C_D reduction was 5.5%, 10.9%, and 87.5% at 0 deg, 4 deg, and 8 deg yaw angle, respectively. Semilenticular wheels provide a lower C_D at medium and large yaw angles compared to corresponding symmetric lenticular wheels. Moreover, the large influence of the ratio of tire width to wheel width on the aerodynamic drag of cycling wheels is confirmed. These results will help riders in their wheel choice and will help manufacturers to design future disk wheels.