If you’re ready to learn more about why sidecar rigs do what they do, we’ll dig a little deeper into the dynamics of cornering. What follows is not a prerequisite to the lessons or exercises in Driving A Sidecar Outfit, but explains more about the dynamics of cornering for those who would appreciate additional information. This chapter will be clearer if you have completed all the practice exercises in the book.
The following is most true for conventional motorcycle/sidecar combinations. Outfits with a narrower track and a taller profile are affected more by cornering forces, and require much more physical input from the driver to keep under control. A high performance rig or a racing outfit with a wide track, low profile, steerable sidecar wheel, etc. is less affected by tipover forces. But all sidecar outfits respond to the same physical forces in much the same way.
The simplistic concept of cornering is that when centrifugal force exceeds gravity pulling the sidecar down, the rig tips over. But that concept is incomplete. There are forces other than centrifugal force that we can harness to keep the rig under control, including steering, hanging off, and tire slip.
The most obvious cornering forces are gravity and centrifugal force. Gravity is a constant. That is, the force of gravity pulling the sidecar down is the same regardless of speed. However, centrifugal force increases as a function of speed. So, it might seem that the tipover forces are determined entirely by speed. In other words, if you increase speed around a turn to the point where centrifugal force exceeds gravity, the outfit should tip over. Ergo, the only practical tactic for preventing a tipover is to reduce speed.
However, let’s note that a sidecar outfit can be driven around a curve with the sidecar wheel off the ground, at various speeds, without tipping over or running wide. Apparently, gravity and centrifugal force aren’t the only forces involved. Steering, hanging off, and tire slip also affect balance.