A counterbalance system for an overhead door is disclosed. The system includes a torsion adjustment comprising a first portion and a second portion, the first and second portions being rotatable relative to one another in a first direction and not in a second direction opposite the first direction. The system also includes an anchor fixed to the first portion, a collar fixed to the second portion, the collar being selectively fixable to a shaft of the overhead door, and a spring coupled between the collar and the anchor. The spring supports at least a portion of the weight of the overhead door as the overhead door is raised and lowered. Rotating the first portion of the torsion calibration collar relative to the second portion of the torsion calibration collar increases torsion in the spring and therefore calibrates the spring to support a desired amount of the weight of the overhead door.