A ratio of 1/4 to one would be signified by .25:1. To find the total ratio, use the pulley ratio formula: Ratio = (Radius of Driven Pulley) / (Radius of Drive Pulley) Example: A handcrank is attached to a drive pulley of 2 inches in radius. The belt runs from the drive pulley to a driven pulley. The driven pulley is 6 inches in radius and is ...