For adjusting the supporting load of a central axle trailer equipped with at least two axles having pneumatic suspensions and a pneumatic suspension system that includes separate pneumatic suspension circuits on the axles with pneumatic suspensions, a method and electronic control device are provided by which the respective quantities of air are separately adjustable. When the current supporting load exceeds a permitted supporting load range, the current supporting load is reduced by separate alteration of the quantity of air in at least one of the pneumatic suspension circuits; and, when the current supporting load is below the permitted supporting load range, the current supporting load is increased by separate alteration of the quantity of air in at least one of the pneumatic suspension circuits.