ISO TS 20825:2003规定了在用机械联轴节磨损部件的最大允许磨损量和极限尺寸，如果遵守，将确保装有此类联轴节的重型商用车辆在道路上的安全运行。它适用于40 mm和50 mm牵引杆联轴节、40 mm和50 mm牵引杆孔、50 mm和90 mm牵引轮主销、钩联轴节和环形孔。

ISO TS 20825:2003 specifies the maximum allowable wear and the limit dimensions of worn components of in-use mechanical couplings, which, when respected, will ensure the safe operation on the road of the heavy commercial vehicles fitted with such couplings. It is applicable to 40 mm and 50 mm drawbar couplings, 40 mm and 50 mm drawbar eyes, 50 mm and 90 mm fifth wheel kingpins, and hook couplings and toroidal eyes.