Conveyor idlers are conveyor wheels that are not powered, but simply freely spin. Generally, a conveyor idler serves to help move the belt along, or provides specific amounts of resistance within a belt and pulley structure. Idlers can also help with gear ratio and other engineering aspects of a conveyor belt system.The two basic types of belt conveyor idlers shall be (i) carrying idlers and (ii) return Idlers subdivided into the following (see Fig. 1). a) Troughing Carrying Idlers — It shall consist of three rolls of equal length and may be either in-line or offset type (see also Fig. 12).