A motor-driven chair has a central drive wheel located beneath the seat and linked so as to be aligned with the facing direction of the seat. A user turns the direction of motion by rotating the seat relative to a surrounding stabilizer assembly so as to turn the seat and the drive wheel towards a direction in which he wishes to move. A suspension arrangement maintains a desired distribution of user load between the drive wheel and the stabilizer assembly. A combination of fixed-axis wheels with castered wheels provides angular anchoring of the stabilizer assembly to facilitate the seat steering process. The entire structure is preferably foldable for easy transportation and storage.