A sorting conveyor for transporting objects and unloading objects at one or more unloading stations adjacent the conveyor. The sorting conveyor includes a conveyor track, a train of conveyor carts connected end-to-end, and an opposed roller motor assembly. The opposed roller motor assembly may include a motor; a support frame attached to the conveyor track for supporting the motor; and a pair of cantilevered, drive rollers connected to the motor and to one pivot block assembly and another pivot block assembly adapted for positioning the drive roller adjacent to one surface of an extended fin driven member. The pivot block assemblies may be coupled together with a self-tensioning adjustment assembly. In some examples, the self-tensioning adjustment assembly may be adapted so that movement of each pivot block assembly mirrors movement of the other pivot block assembly.