Abstract: A wheel rim (10) has a tire bead retaining means (20,21) disposed on the axially inner margin of at least one of its bead seats (14,15). The bead retaining means comprises a plurality of radially outwardly protruding humps (22) formed integrally with the rim. The humps (22) each extend circumferentially so as to merge one into another, and each hump has a radial height that gradually and continuously increases from a minimum height to a maximum height (H), and subsequently decreases back to the minimum height. The outer peripheral surface (28) of the bead retaining means between points (29) of maximum height (H) is a continuous arc having a radius (R.sub.2) greater than the radius (R.sub.1) of the rim bead seats, and at the points (31) of minimum height forms a tangent to a circle (27) concentric with the rim.