A technique for reducing the likelihood of fatigue damage to a wheel rim assembly (11) of the type having an annular wheel rim (13) with a first bead flange (19), a second separable bead flange (15, 21), and a retaining ring (17) disposable within a groove (35) in the wheel rim to secure the separable bead flange to the wheel rim includes forming the retaining ring to have an annular bead (41), a portion of which has an arcuate cross-sectional configuration by shaping the annular bead, in cross-section, as at least two tangentially joined circular segments (43, 45) of unequal radii (27, 29). The separable bead flange is formed to have a concave retaining ring engaging annular surface (25) which, in cross section has a finite radius of curvature (5) and the retaining ring is formed to have a separable bead flange engaging convex annular surface (23) which, in cross-section, has a finite radius of curvature (61).