A round baler is disclosed for forming crop material into cylindrical bales. The baler has a main frame, a pair of side walls, a crop pickup mounted on the main frame, and a tailgate pivotally connected to the main frame. The tailgate is operative between a closed position during which a bale is being formed in an expandable chamber, and an open position during which a formed bale is being discharged from the chamber. A sledge assembly, pivotally mounted on the main frame for movement between a bale starting position and a full bale position, has crop engaging transverse rolls for urging the crop material along a spiral path in the chamber for starting and forming a bale. An apron is supported along a continuous path on the main frame and tailgate by a plurality of rotatable guide members. The path has an inner course that cooperates with the sledge rolls on the sledge assembly to define the chamber. A take up assembly, affixed to the sledge assembly, moves therewith between the bale starting position and full bale position. Structural twisting during uneven loading of the bale chamber is countered by a hydraulic cylinder affixed between the main frame and the sledge assembly.