Aerodynamics: The purpose of the pace car is to rule out most aerodynamic concerns; to block the wind for the biker. Donhou added wooden extensions to the car to create a little wind-free haven for him to slip into. Still, two aerodynamic considerations remained pertinent. First, Donhou had to be sure his body was low enough to be completely immersed in the hollow; hence, the custom low-hanging, A-frame handlebars. Next, since the Zephyr isn't low enough to the ground to block the tires from wind and drag, Donhou had to choose his wheels based on their aerodynamics.