A conveying system has a roller and a shaft-hub assembly with a kingpin (81), an expansion element (83) and a hub (82). The kingpin has a cross-section corresponding to a cross-section of the hub so that the kingpin is fixed radially to the hub. The kingpin (81) is fixed rotationally to the hub (82). The expansion element in a relaxed state, has an external diameter that exceeds the internal diameter of the hub. The expansion element also is deformed elastically when the kingpin is disposed in the hub so that the external peripheral region (831) of the expansion element shifts from the relaxed position. Axial displacement of the external peripheral region of the expansion element is coupled with a reduction in the external diameter so that the reduced external diameter of the expansion element corresponds to the internal diameter of the corresponding internal peripheral region of the hub.