Abstract: A caster assembly includes a wheel bracket, a wheel attached to the wheel bracket, a shaft about which the wheel bracket is free to rotate, and a cam assembly. The caster assembly is attached to the underside of a caster board, where the shaft is fixed perpendicular to the board, and the cam assembly comprises a cam track fixed to the board with the shaft at its center and a cam follower fixed to the wheel bracket. The cam track is geometrically formed to have a number of valleys and peaks along its circumference. As the wheel bracket rotates about the shaft, the cam follower engages the cam track and causes the board and the wheel assembly to move away and towards each other. The resulting forces generate or maintain a generally forward motion in the caster board, without the need for further efforts by a rider. The caster assembly further permits the rider to travel backwards as well as forwards. The cam track is easily changeable by the rider to accommodate various user preferences and skill levels.