Abstract: A protection structure for outer shell of a hub comprises: a hub and an outer shell mounted at one end of the hub, the outer shell is provided at one end close to the hub with an enlarged flange, on an outer peripheral surface of the outer shell are annularly and spaced-apart formed a plurality of splines and at least one positioning rib, at least at one side of each splines is disposed with a protecting member whose material is different from that of the outer shell. By such arrangements, the protecting member can be assembled with a sprocket to prevent the sprocket from touching the splines. Thus, damages of the outer shell of the hub are prevented.

Abstract: A protection structure for outer shell of a hub comprises: a hub and an outer shell mounted at one end of the hub, the outer shell is provided at one end close to the hub with an enlarged flange, on an outer peripheral surface of the outer shell are annularly and spaced-apart formed a plurality of splines and at least one positioning rib, at least at one side of each splines is disposed a protection structure whose material is different from that of the outer shell. By such arrangements, the protection structure can be assembled with the cassette to prevent the cassette touching the splines, thus preventing the damage of the outer shell of the hub.

Abstract: A hub shell confines an axial bore therethrough and has first and second annular mounting flanges formed integrally on an external surface thereof adjacent to first and second axial end portions of the axial bore. The hub shell is constituted by two pieces and a tubular connector that interconnects the two pieces. Each piece has an annular end portion which is formed opposite to a respective one of the first and second axial end portions and which has an annular flange that extends inwardly and radially from the periphery of the annular end portion and that abuts against the annular flange of the other piece when the first and second pieces are disposed side by side such that the axial bores are in alignment. The tubular connector is disposed entirely within the two pieces and has two outwardly and radially extending flange portions which clamp the annular flanges of the pieces so as to interconnect the latter.