A two-degree-of-freedom active suspension is analyzed for its performance sensitivity as a function of the linear feedback gains of the control system. The active suspension is equipped with a microcomputer-controlled pneumatic actuator and has a relatively low car body to truck mass ratio and low primary and secondary natural frequencies. Physically, this set of data approximates some magnetically levitated vehicles. The performance is examined through car body vertical acceleration, truck-guideway gap variations, and suspension working space excursions. The results show that acceptable performance can be obtained with incomplete state variable feedback control.