Gates Drive

This is the first generation of belt interface from Gates which is no longer in production since it has been replaced by the Centertrack system. Unlike Centertrack, this interface doesn't have a track cut down the center to prevent the belt from sliding off the sprocket so belt tension and alignment are critical. Just like a chain, a belt operates best in a straight line, if it's operating on an angle it will cause premature wear and not function smoothly. In addition to proper beltline and frame alignment Gates also used flanges on their sprockets and chainrings to help keep the belt centered which added extra weight. 

This series of Gate's belts were called CDC and came in a wide array of different lengths/tooth counts.