A rear dual wheel assembly with a novel self-locking mechanism in a heavy transport vehicle comprises a common axle hub, an inboard wheel assembly and an outboard wheel assembly at each side of the heavy transport vehicle; wherein each outboard wheel assembly comprises, a knave for connecting the wheel rim to the common axle hub; a removable bead seat (412, 415) in an outer and an inner portion of the outboard wheel;; a two-piece segmented saddle lock ring (409a, 409b) and an endless ring in the inner portion; a split lock ring in the outer portion; a tyre flange (403, 416) at both outer and inner portion; and wherein each inboard wheel assembly comprises, a knave for connecting the wheel rim to the common axle hub; a removable bead seat in an outer portion of the inboard wheel; a fixed bead seat in an inner portionof the inboard wheel; a split lock ring; a tyre flange (203, 212) at both outer and inner portion; characterized in that the two-piece segmented saddle lock ring (409a, 409b) in the inner portion being retained on the wheel rim by the endless ring; an O-ring is provided at the inner and the outer portion (400a, 400b) of the outboard wheel; an O-ring is provided at the outer portion of the inboard wheel; and an inner surface of the endless ring is provided with a taper that is pressed against a taper provided on the two-piece segmented saddle lock ring (409a, 409b); wherein the taper provided on the two-piece segmented saddle lock ring (409a, 409b) is a self-locking type and the half angle of the conical frustum with respect to a wheel rim axis may vary depending on the wheel size, torque and other tribological conditions. a common axle hub, an inboard wheel assembly and an outboard wheel assembly at each side of the heavy transport vehicle; wherein each outboard wheel assembly comprises, a knave for connecting the wheel rim to the common axle hub; a removable bead seat (412, 415) in an outer and an inner portion of the outboard wheel;; a two-piece segmented saddle lock ring (409a, 409b) and an endless ring in the inner portion; a split lock ring in the outer portion; a tyre flange (403, 416) at both outer and inner portion; and wherein each inboard wheel assembly comprises, a knave for connecting the wheel rim to the common axle hub; a removable bead seat in an outer portion of the inboard wheel; a fixed bead seat in an inner portionof the inboard wheel; a split lock ring; a tyre flange (203, 212) at both outer and inner portion; characterized in that the two-piece segmented saddle lock ring (409a, 409b) in the inner portion being retained on the wheel rim by the endless ring; an O-ring is provided at the inner and the outer portion (400a, 400b) of the outboard wheel; an O-ring is provided at the outer portion of the inboard wheel; and an inner surface of the endless ring is provided with a taper that is pressed against a taper provided on the two-piece segmented saddle lock ring (409a, 409b); wherein the taper provided on the two-piece segmented saddle lock ring (409a, 409b) is a self-locking type and the half angle of the conical frustum with respect to a wheel rim axis may vary depending on the wheel size, torque and other tribological conditions.