This work is basically a dirigibility study applied to tricycles of human traction, HPT - Human Powered Tricycle. The behavior of the vehicle is simulated in a track with compacted floor, contend curves, straight line, up and down grades. A simplified mathematical model is used to model the system (vehicle + cyclist). As the system of equations obtained is extremely coupled and non-linear, it is necessary to use numeric procedures to solve the equations and to obtain the behavior of the system during its path in the racetrack. The influences of the track and the mass center position of the vehicle in its stability, the behavior of the vehicle using chainset transmissions and CVTs (Continuously Variable Transmission) are also analyzed.