A wheel hub assembly for motor vehicles, provided with a first hub, which is stationary, a second hub, which is rotatable, and a bearing unit in turn having a radially outer ring provided with respective radially external raceways, at least one radially inner ring provided with respective radially internal raceways, at least one row of rolling bodies, positioned between the corresponding internal and external raceways, at least one sealing device, positioned on the axially inner side with respect to the at least one row of rolling bodies. A metal deflector configured so as to allow the water to drain and protect the area of the sealing device from the external contaminant is mounted by interference on the rotating hub.