A screw compressor includes a housing having an inlet for receiving gas to be compressed by the compressor and an outlet for discharging pressurized compressed gas. A pair of meshing threaded rotors, each rotor having an axis and being rotatably received in the housing, each rotor having a first end near the inlet and a second end near the outlet. A bearing rotatably carrying each rotor about its axis and positioned near the first end and the second end of each rotor. A conduit formed in the housing in selectable fluid communication with at least one bearing and a force generating source from a pressurized fluid source, the force generating source selectably providing a force in a radial direction relative to the axis of the at least one bearing.