A self-actuating tension head for a strapping machine includes a body defining a strap path, a drive wheel, a tension wheel a fixed distance from the drive wheel and a pinch wheel. The strap path extends between the tension and pinch wheels. A first link operably connects the drive and tension wheels and defines a first pivot arm that is pivotable about the drive wheel axis of rotation. A second link operably connects the tension and pinch wheels and defines a second pivot arm that is pivotable about the pinch wheel axis and movable along the second pivot arm to move the tension wheel into and out of engagement with the pinch wheel. The first and second pivot arms define an energizing angle therebetween that decreases as the tension wheel is moved into engagement with the pinch wheel and increases as the tension wheel is moved out of engagement with the pinch wheel.