Ribbon coil spring anchor mount system for use in a window counterbalance assembly

A counterbalance system for counterbalancing the weight of a window sash of a window frame, said system comprising:

• a guide track disposed within said window frame for guiding movement of said window sash;
• a mounting slot formed in said guide track;
• a coil spring of wound steel ribbon having a first end, an opposite second end, and a transition zone, wherein said coil spring has a constant first width between said first end and said transition zone and a constant second width between said transition zone and said second end, wherein said constant second width is less than said constant first width;
• a first bend in said coil spring between said transition zone and said second end;
• a second bend in said coil spring between said first bend and said second end;
• wherein said first bend and said second bend form a slot engagement configuration that engages said mounting slot formed in said guide track.