An arrangement including a portion of a radially outer lateral surface of an inner ring of wheel hub on which an annular step is formed on the side of a constant velocity joint. The step is an L-shaped fold of a sleeve portion of a first shield that is protrudingly mounted, a flange portion of which shield radially extends so as to protrude towards an outer ring of a wheel hub, in front of a flange portion of a second shield; the L-shaped fold defines, with a wing thereof, a tubular element arranged straddling wheel hub and an outer ring of the constant velocity joint, which has a free end supporting an annular seal; an annular signal generating insert completely covers a face of the flange portion where it is provided with a shallow recess defining, together with the L-shaped fold, a thrust shoulder for mounting the first shield.