So, you’ve heard that three wheel vehicles are inherently unstable, and prone to turning over while cornering, and you want to know what makes the Can-Am Spyder three wheeled motorcycle different? You came to the right place.
When any vehicle turns, it produces a centrifugal force which manifests as a pushing force to the outside of the turn. Since the strongest point of resistance is the traction of the tire against the road surface, and with the center of gravity above that, the combined forces of friction (the tire traction) and centrifugal force produce a tendency to rotate the vehicle over the traction point. In layman’s terms, the vehicle starts to roll over the outside wheels. Motorcycles counteract this force by leaning into the corner, channeling the centrifugal force down through the motorcycle to the tires, negating the rollover tendency. The Can-Am Spyder does not lean, however, and therefore must address this issue in a different way.
Most Can-Am Spyder riders will never experience enough force to cause this effect, but since it is a possibility, Can-Am went to great lengths to insure that the Spyder comes under control immediately upon any threat of rollover. To this end the Spyder employs advanced sensors to detect imminent rollover, and when so detected, simultaneously cuts power to one of the two cylinders while applying the brakes. Both of these measures combine to reduce the forward velocity that is one of the components producing the centrifugal force.
By regulating the power to arrest imminent rollover, the Can-Am Spyder continues to allow the operator to continue through the turn on the desired and expected course, albeit at a reduced speed. The only other way of attempting to arrest rollover, without designing a leaning machine, would be to regulate the other component of the turn, that being the tightness of the turn, and would both require an extensive linkage system to adjust the steering automatically, and would result in the unsettling, and unsafe, experience of the Spyder failing to follow the desired path, regardless of the input of the rider. I, for one, and glad the Spyder’s designers chose to implement their design strategy, for I am much more comfortable with the Spyder slowing down in a corner than it wandering its own course in a corner.
