A multi-function Pilates exercise apparatus featuring a foldable frame (200-203), a counterbalance mechanism (271), a wheeled base (90), a rotatable pulley riser with a flexible pulley mount (112), gear changing apparatus (FIG. 9) and adjustable footbar (471). The frame is designed to fold into an upright position and to be rolled to a desired location. The pulley assemblies may be rotated and positioned below the carriage rails. The gear changing apparatus permits the user to adjust the carriage position with a single handed operation. The exercise system includes a reformer, a pole apparatus, and mat mode including a long/short box.