Patent ID: 8192315

Claim:
In 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 said back-side and said front-side sections and coextensive with both the back-side and front-side sections, (b) a front-side driving pulley frictionally engaged with the front-side section of the V-ribbed belt, and (c) a flat-faced back-side pulley frictionally engaged with the back-side section of the V-ribbed belt, the improvement wherein the outer surface of the back-side section of the V-ribbed belt has a maximum thickness of about 1.3 mm and comprises raised features separated by low regions having a depth of 0.1 mm to 1.0 mm alternating therebetween, wherein the raised features have a uniform center-to-center distance and contact the back-side pulley forming a reduced contact patch with the back-side pulley, the reduced contact patch having an area about 20% to about 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.