Motorbike Aerodynamics - 10 mph faster with Joseph Katz

In this video, we’ll discuss the motorbike aerodynamics with together with Joseph Katz, author of the famous book “race car aerodynamics”, professor at the San Diego State University and passionate motorbike rider. Before we move on to the interview, let’s summarize some basic aspects of motorbike aerodynamics and how they differ from cars: First of all, the drag: the frontal area, which is the area when looking at an object from the front, is much smaller for a motorbike. But to get the total drag on an object, you need to multiply this frontal area by the drag coefficient, which is much, much larger for a motorbike, offsetting the benefit of the smaller frontal area: it is filled with exposed bits of geometry like the wheels, brakes, and so on, and the surface the air needs to follow is hardly a smooth one: it’s full of abrupt changes like the end of the wind shield causing the flow to detach. And then there’s the rider, a massive disturbance to the air. So, the drag coefficient of a motorbike is easily double or more than that of a modern-day car. Second of all, the centre of pressure, which is the point where the total sum of the pressure is acting, is quite high above the ground. With respect to the contact point of the rear wheel on the ground, this tends to push the motorbike backwards, lowering contact pressure on the front wheel, which reduces steering control. As the aerodynamic drag force increases with the square of velocity, this can become problematic at high speeds. So, trying to get the center of pressure as low as possible is crucial for motorbikes. A low rider position is a good start. Another way to balance things is to create down force on the front wheel to counteract this back-flipping moment on the bike. In the interview, we cover the following topics: - Effects of leaning on aerodynamics - Engine performance - AMA superbikes - Rider position - Rear tire wear - Active aerodynamics - Wind tunnel testing - Centre of pressure - Ducati wings - Lateral forces - Helmet vibration - Better engine performance via RAM air

Supported by

  • Solar Impulse
  • iMec
  • Voxdale

Code contributions by

  • KU Leuven
  • Inholland
  • Linkoping University