So why only 4 stars?
Run after about 20 minutes the unit began to creak on terribly and 5 minutes later it cracked even in the clock. After several hours of search (dismantle and grease) I had found and solved the problems: A kick shell which is made of plastic, had scoured the steel tube, which rotates slightly. Because the holes in the sheets, on which the foot plates are screwed, are not round but oval, you can see the shells before tightening the screws several millimeters back and forth. The right one millimeter shell moved away from the steel tube and it creaked nothing. Now it cracked just yet ... Here the plastic cover of the roles has been to blame. The Upper pulled slightly upwards managed relief, the Lower screwed slightly loose so that they can move, also eliminated this problem. Now the unit is running as it should! The role panel, incidentally, was assembled by Kettler, so no assembly error of mine.