A wheel assembly comprising: - a wheel comprising: i) an outer crown or rim for mounting a tire, comprising a cylindrical channel wall having an outer channel surface and an inner channel surface (10"), said channel wall being crossed by a channel hole having an inlet on the inner channel surface (10") and an outlet on the outer channel surface; ii) a hub for fixing to an axle of the vehicle, integral with the crown, having an outer hub surface and an inner hub surface (20"), said hub being crossed by a through-hole for inflating the tire, having an inlet on the inner hub surface (20") and an outlet on the outer hub surface, and by a hub hole having an inlet on the outer hub surface and an outlet on the inner hub surface (20"); - a first fitting separably applied to the hub, provided with at least a first internal conduit suitable for connecting the outlet of the through-hole with the hub hole; - a non-return valve, housed in the first fitting, along the first inner conduit, normally closed, suitable to open to allow air under pressure to enter from the inlet of the through-hole; characterized in that it comprises: - a second fitting, provided with at least one second internal conduit, which is applied separably between the hub and the crown so as to connect the outlet of the hub hole with the entrance of the channel hole; wherein the second fitting comprises: i) an attaching portion provided with holes for inserting bolts in abutment with the hub, and in particular in contact with the inner hub surface (20"), and ii) a perforated shank protruding from the attaching portion engaging with the channel hole. - a wheel comprising: i) an outer crown or rim for mounting a tire, comprising a cylindrical channel wall having an outer channel surface and an inner channel surface (10"), said channel wall being crossed by a channel hole having an inlet on the inner channel surface (10") and an outlet on the outer channel surface; ii) a hub for fixing to an axle of the vehicle, integral with the crown, having an outer hub surface and an inner hub surface (20"), said hub being crossed by a through-hole for inflating the tire, having an inlet on the inner hub surface (20") and an outlet on the outer hub surface, and by a hub hole having an inlet on the outer hub surface and an outlet on the inner hub surface (20"); i) an outer crown or rim for mounting a tire, comprising a cylindrical channel wall having an outer channel surface and an inner channel surface (10"), said channel wall being crossed by a channel hole having an inlet on the inner channel surface (10") and an outlet on the outer channel surface; ii) a hub for fixing to an axle of the vehicle, integral with the crown, having an outer hub surface and an inner hub surface (20"), said hub being crossed by a through-hole for inflating the tire, having an inlet on the inner hub surface (20") and an outlet on the outer hub surface, and by a hub hole having an inlet on the outer hub surface and an outlet on the inner hub surface (20"); - a first fitting separably applied to the hub, provided with at least a first internal conduit suitable for connecting the outlet of the through-hole with the hub hole; - a non-return valve, housed in the first fitting, along the first inner conduit, normally closed, suitable to open to allow air under pressure to enter from the inlet of the through-hole; - a second fitting, provided with at least one second internal conduit, which is applied separably between the hub and the crown so as to connect the outlet of the hub hole with the entrance of the channel hole; wherein the second fitting comprises: i) an attaching portion provided with holes for inserting bolts in abutment with the hub, and in particular in contact with the inner hub surface (20"), and ii) a perforated shank protruding from the attaching portion engaging with the channel hole. i) an attaching portion provided with holes for inserting bolts in abutment with the hub, and in particular in contact with the inner hub surface (20"), and ii) a perforated shank protruding from the attaching portion engaging with the channel hole.