A method of reducing drag on the web of a positive displacement sorter is used with a web made up of a plurality of parallel slats interconnected at their opposite ends with chain assemblies in an endless loop. A plurality of pusher shoes each travel along at least one of said slats. The sorter further includes a driven sprocket assembly and a non-driven sprocket assembly. Each of the sprocket assemblies includes at least two sprockets on a shaft, each for engaging one of the chain assemblies. The sprocket assemblies support the chain assemblies at opposite ends of the web. The method includes auditing the sorter including determining if the slats are skewed with respect to the direction of travel of the web. If it is determined that the slats are skewed, then the chain assemblies and the non-driven sprocket assembly are modified. The chain assemblies are modified by adding side thrust wheels on opposite sides of the web. The non-driven sprocket is modified by locking the sprockets to the shaft such that the sprockets rotate together.