The invention provides a method for preparing the manufacturing of bales of harvested crop material with a baler (70) having a bale chamber (80) comprising chamber doors pivotably connected to a fixed frame part. Upon obtaining (10) at least one crop parameter (40), a door angle value (α) between two side sections (160a, 160b) of a door is selected and the position of one of the side sections (160a) with respect to the other one (160b) is adapted in accordance with the selected door angle value (α). A corresponding baler (70) and a control system for such baler (70) are also provided.
