Abstract: A floating brake disc assembly includes a disc body and fasteners. The disc body includes a hub member and a brake rotor circumferentially around the hub member. The hub member and the brake rotor together defines connecting holes. Each fastener includes a rivet pin, a coned-disc spring and a protection washer next to the coned-disc spring. The coned-disc spring has a conical body and a positioning post axially extending from the conical body. The protection washer defines in an inner wall of its central bore a dent for reception of the respective positioning post of the coned-disc spring. The rivet pin passes through the connecting hole of the disc body, a central hole of the coned-disc spring and the central bore of the protection washer so as to fasten the hub member and the brake rotor together while allowing slight floating movement of the brake rotor relative to the hub member therebetween.