A method and compositions for reducing friction between relatively slideable components is described comprising applying to a slideably engaging surface of the slideable components a lubricating amount of at least one Newtonian, or non-Newtonian, metal overbased salt of a carboxylic acid wherein the metal is selected from the group consisting of lithium, calcium, sodium, barium, magnesium, and mixtures thereof, and the carboxylic acid comprises at least one linear unsaturated hydrocarbon group containing from about 8 to about 50 carbon atoms. The types of slideable components contemplated include flat bearings, rotating bearings, lead screws and nuts, gears, hydraulic systems, and pneumatic devices. The inventors have discovered that applying a metal overbased salt of the aforesaid carboxylic acids results in a remarkable reduction in static and dynamic coefficients of friction and provides anti-wear protection of an extreme pressure agent without requiring auxiliary friction-modifying agents or auxiliary extreme pressure agents.