A crankcase lubricating oil composition comprises an oil of lubricating viscosity, in a major amount, and, in respective minor amounts, a boron-containing additive and one or more co-additives, wherein the lubricating oil composition has greater than 200 ppm by mass of boron, less than 600 ppm by mass of phosphorus and less than 4000 ppm by mass of sulfur, based on the mass of the oil composition. Such compositions demonstrate provide improved wear performance.