Front wheel alignment due to pulling to right side of the road.
Reason found: the upper one of the 2 large bolts holding the left side shock adsorber was not completely tightened. Rot cause: the former owner had replaced both front shock assorbers, but the bolts were not cleaned from massive rust, so the nut did not hold the adsorber properly only slightly (however 200 Nm torque applied at the first try for tightening it).
Even the knocking sound disappeared at cornering to right.
I will keep the annual wheel alignment proposal - it worth the money (after purchased brand new set of winter and summer tyres).