A baler (10) is disclosed. The baler (10) comprises: a frame (20)； a bale-wrapping system including a surface-wrap guide roller (32)； a counterknife assembly including a support member (74) rotatably mounted to the frame (20) and a counterknife arm (72, 94) mounted to the support member (74), the counterknife arm (72, 94) pivoting to cause a counterknife (34) to cut surface wrap when the support member (74) rotates with respect to the frame (20)； a pulley member (40) attached to and rotating with the guide roller (32)； a traction device (54) surrounding, at least in part, the pulley member (40)； a tensioning assembly (30) attached to the frame (20) at a frame attachment point (90) of the tensioning assembly (30), the tensioning assembly (30) including a lost motion linkage limited by a stop to a limited range of motion with respect to the frame (20), the lost motion linkage being attached to a first end of the traction device at a brake attachment point (88) of the tensioning assembly (30), and attached to the support member (74) at the frame attachement point (90) of the tensioning assembly (30)； and a counterforce assembly (28) attached to a second end of the traction device (54) at a brake attachment point (56) of the counterforce assembly (28), and pivotably attached to the frame (20) at a frame attachment point (58) of the counterforce assembly (28)； wherein rotating the support member (74) in a braking direction with respect to the frame (20) causes the tensioning assembly (30) to pivot in the braking direction to move the lost motion linkage toward the stop such that the stop prevents further movement of the lost motion linkage with respect to the frame (20), the tensioning assembly (30) thereby applying a first tensioning force to the traction device (54), the first tensioning force being resisted by the first counterforce assembly (28), via the brake attachment point (56) of the counterforce assembly (28), to impose a braking force on the pulley member (40)
