A V-ribbed belt pulley system comprising: (a) a V-ribbed belt having an outer back-side section, an inner front-side section having a plurality of laterally spaced longitudinally extending v-ribs, and a load-carrying section disposed between the outer back-side and the inner front-side sections and coextensive with both the back-side and front-side sections, (b) a front-side driving pulley frictionally engaged with the inner front-side section of the V-ribbed belt, and (c) a flat-faced back-side pulley frictionally engaged with the outer back-side section of the V-ribbed belt, characterized by: the outer back-side section of the V-ribbed belt having a thickness of 0.76 mm to 1.3 mm and having formed therein a plurality of continuous laterally spaced, longitudinally extending raised features separated by continuous longitudinally extending low regions along the length of the back-side section having a depth of 0.1 to 1.0 mm alternating therebetween, wherein the raised features have a uniform center-to-center distance and, when viewed in cross-section across the lateral width of the belt, the raised features have at least one of curved, semi-circular, elliptical, sinusoidal, triangle, rectangular shapes repeating thereacross while alternating with the low regions, which have at least one of flat or curved shape, wherein only the raised features contact the back-side pulley forming a reduced contact patch with the back-side pulley, and wherein the reduced contact patch has an area from 20% to 50% of the area of a full contact patch that would be formed between the back-side pulley and a flat-faced belt over the same length of engagement, and the longitudinally extending low regions direct contaminants away from the contact patch over time thereby, after continued use, the coefficient of friction of the outer back-side section increases. (a) a V-ribbed belt having an outer back-side section, an inner front-side section having a plurality of laterally spaced longitudinally extending v-ribs, and a load-carrying section disposed between the outer back-side and the inner front-side sections and coextensive with both the back-side and front-side sections, (b) a front-side driving pulley frictionally engaged with the inner front-side section of the V-ribbed belt, and (c) a flat-faced back-side pulley frictionally engaged with the outer back-side section of the V-ribbed belt, the outer back-side section of the V-ribbed belt having a thickness of 0.76 mm to 1.3 mm and having formed therein a plurality of continuous laterally spaced, longitudinally extending raised features separated by continuous longitudinally extending low regions along the length of the back-side section having a depth of 0.1 to 1.0 mm alternating therebetween, wherein the raised features have a uniform center-to-center distance and, when viewed in cross-section across the lateral width of the belt, the raised features have at least one of curved, semi-circular, elliptical, sinusoidal, triangle, rectangular shapes repeating thereacross while alternating with the low regions, which have at least one of flat or curved shape, wherein only the raised features contact the back-side pulley forming a reduced contact patch with the back-side pulley, and wherein the reduced contact patch has an area from 20% to 50% of the area of a full contact patch that would be formed between the back-side pulley and a flat-faced belt over the same length of engagement, and the longitudinally extending low regions direct contaminants away from the contact patch over time thereby, after continued use, the coefficient of friction of the outer back-side section increases.