Disc assembly for disc brake and energizing ring, or flywheel, comprising: - a disc for disc brake which develops about a rotation axis defining an axial direction (A-A), a radial direction (R-R), orthogonal to said axial direction (A-A), and a tangential or circumferential direction (T-T) perpendicular to said axial direction (A-A) and said radial direction (R-R); - said disc being of a first material less resistant to corrosion and comprising: - a braking band adapted to cooperate with opposite braking surfaces (5, 6) thereof with a brake caliper; - a bell for connecting the brake disc to a hub of a vehicle; - a connecting portion between said braking band and said bell; - a connecting portion of an energizing ring connected cantilevered to said bell so as to avoid to interfere with said braking band and forming an end surface arranged parallel to the radial direction (R-R); - said assembly further comprising an energizing ring comprising: - an energizing ring body having an energizing side, opposite to said disc, and coupling side, facing said disc; - a plurality of projections and/or recesses provided in said energizing side; - said energizing ring being of a second material more resistant to corrosion than the first material; - at least a coupling portion cantilevers from said energizing ring body in axial direction (A-A) and includes a free end portion; characterized in that - said free end portion of the coupling portion is received in said connecting portion of an energizing ring of the disc passing through said radial end surface; - said connecting portion of an energizing ring closely surrounding said free end portion of the coupling portion, leaving said energizing ring body free. - a disc for disc brake which develops about a rotation axis defining an axial direction (A-A), a radial direction (R-R), orthogonal to said axial direction (A-A), and a tangential or circumferential direction (T-T) perpendicular to said axial direction (A-A) and said radial direction (R-R); - said disc being of a first material less resistant to corrosion and comprising: - a braking band adapted to cooperate with opposite braking surfaces (5, 6) thereof with a brake caliper; - a bell for connecting the brake disc to a hub of a vehicle; - a connecting portion between said braking band and said bell; - a connecting portion of an energizing ring connected cantilevered to said bell so as to avoid to interfere with said braking band and forming an end surface arranged parallel to the radial direction (R-R); - said assembly further comprising an energizing ring comprising: - an energizing ring body having an energizing side, opposite to said disc, and coupling side, facing said disc; - a plurality of projections and/or recesses provided in said energizing side; - said energizing ring being of a second material more resistant to corrosion than the first material; - at least a coupling portion cantilevers from said energizing ring body in axial direction (A-A) and includes a free end portion; characterized in that - said free end portion of the coupling portion is received in said connecting portion of an energizing ring of the disc passing through said radial end surface; - said connecting portion of an energizing ring closely surrounding said free end portion of the coupling portion, leaving said energizing ring body free. - a braking band adapted to cooperate with opposite braking surfaces (5, 6) thereof with a brake caliper; - a bell for connecting the brake disc to a hub of a vehicle; - a connecting portion between said braking band and said bell; - a connecting portion of an energizing ring connected cantilevered to said bell so as to avoid to interfere with said braking band and forming an end surface arranged parallel to the radial direction (R-R); - said assembly further comprising an energizing ring comprising: - an energizing ring body having an energizing side, opposite to said disc, and coupling side, facing said disc; - a plurality of projections and/or recesses provided in said energizing side; - said energizing ring being of a second material more resistant to corrosion than the first material; - at least a coupling portion cantilevers from said energizing ring body in axial direction (A-A) and includes a free end portion; characterized in that - said free end portion of the coupling portion is received in said connecting portion of an energizing ring of the disc passing through said radial end surface; - said connecting portion of an energizing ring closely surrounding said free end portion of the coupling portion, leaving said energizing ring body free. - an energizing ring body having an energizing side, opposite to said disc, and coupling side, facing said disc; - a plurality of projections and/or recesses provided in said energizing side; - said energizing ring being of a second material more resistant to corrosion than the first material; - at least a coupling portion cantilevers from said energizing ring body in axial direction (A-A) and includes a free end portion; - said free end portion of the coupling portion is received in said connecting portion of an energizing ring of the disc passing through said radial end surface; - said connecting portion of an energizing ring closely surrounding said free end portion of the coupling portion, leaving said energizing ring body free.