A round baler is described having a housing with two sidewalls and a plurality of belts arranged side by side within the housing between the sidewalls and guided over rolls of which at least some are mounted movably to permit a baling to increase in diameter as the bale being formed grows in size. The movable rolls are supported by a belt tension arm assembly having radius arms extending from an axle that is rotatable relative to the housing about an axis parallel to that of the rolls. The rolls nearest the sidewalls of the housing are cantilevered mounted on the belt tension arm assembly to extend laterally beyond the radius arms.
