Three Wheeled Vehicle Dynamics

Comparisons are made between a three wheeled vehicle with two wheels on the front axle, a three wheeled vehicle with two wheels on the rear axle, and a standard four wheeled vehicle. Each vehicle’s lateral stability, rollover stability during lateral acceleration, rollover stability while braking in a turn, and rollover stability while accelerating in a turn are determined. It is shown that for lateral stability, the three wheeled vehicle with two wheels on the rear axle is more stable than the four wheeled vehicle, which is in turn more stable than the three wheeled vehicle with two wheels on the front axle. For rollover stability the four wheeled vehicle is always stable as long as the vehicle’s track width is greater than twice its center of mass height. The three wheeled vehicles are less stable than the four wheeled vehicle in terms of rollover stability. Vehicle track width to center of mass height relationships which govern rollover stability are developed for the three wheeled vehicles. Provided these relationships are observed, three wheeled vehicles can offer safe alternatives to four wheeled vehicles.