A tire inflation system that couples to the wheel of a vehicle, the tire inflation system including a pumping ring that rotates with the wheel; a positioning system rotatably coupled to the wheel, the positioning system including a positioning mechanism and an eccentric mass; a planetary roller disposed in non-slip contact with the pumping ring and the positioning system; and a flexible diaphragm that defines a pump cavity, wherein relative motion between the pumping ring and positioning system is translated by the planetary roller into an occluding force that deforms the diaphragm to occlude the pump cavity. Relative motion between the pumping ring and the positioning system is achieved by coupling the eccentric mass to the positioning mechanism to offset the center of mass of the positioning system from the center of rotation of the positioning system.