A cap member of an internally geared hub includes a cap body and a first seal member. The cap body has a side wall part and an outer cylindrical part provided with an internally threaded section that meshes with external threads of a cylindrical member of a hub shell. The side wall part has an opening in the center thereof configured such that a driver inside the hub shell extends there-through. The side wall part is configured to extend radially inward from a first axial end section of the outer cylindrical part. A first seal member is arranged on the side wall part of the cap body and configured to contact the driver thereby creating a seal around the driver.