FIG. 1 is a left side elevational view of a castor with hub which forms my new design; FIG. 2 is a right side elevational view thereof; FIG. 3 is a rear elevational view thereof; FIG. 4 is a front elevational view thereof; FIG. 5 is a bottom plan view thereof; FIG. 6 is a top plan view thereof; and, FIG. 7 is an enlarged perspective view showing the front, left side and top thereof.