A method of enhancing the operating life of roller bearings assemblies (B) subject to oil-out conditions is disclosed. The method comprises applying a tribological metal carbide reinforced amorphous hydrocarbon coating layer (16) over either the sliding surfaces (SS) or the rolling surfaces (RS) of the bearing assembly rolling elements (RE), but is preferably applied at least to the sliding surfaces of the rolling element. The coating has a thickness determined according to the equation: Formula (I), where d=coating thickness P=is the ratio of force applied to the rollers/contact area; n=the number of rollers; (t−t0)=the desired operating time after oil-out condition starts; and K′ is the Archard constant. d K ′ = Pv n ⁢ ( t - t 0 ) , ( 1 )