A spiral conveyor system may include a drum and a conveyor belt traveling helically about the drum from an entrance end to an exit end of the drum, and a rib associated with the drum, wherein the rib extends radially from a surface of the drum. A length of the rib extends along the length of the drum from a first end of the rib to a terminus of the rib proximate the entrance end of the drum. In addition, a height of the rib above of the surface of the drum varies along the length of the rib. Further, the rib includes at least one drive face, wherein the conveyor belt includes at least one belt surface configured to engage the at least one drive face, and wherein the drum includes a smooth ribless portion between the terminus of the rib and the entrance end of the drum.