This part of ISO 789 specifies test procedures for determining the power available at the drawbar on agricultural tractors of the wheeled, track-laying or semi-track-laying type. The statement of power rating of the drawbar is specified in 6.4.
GSO ISO 789-9:2013 history
2013GSO ISO 789-9:2013 Agricultural tractors -- Test procedures -- Part 9: Power tests for drawbar