A braking device for a vehicle, comprising a brake disc of a disc brake , suitable for rotating about a rotation axis (A-A), wherein said disc comprises a disc body ; and wherein said disc body comprises a braking band having opposite braking surfaces ; and wherein said disc body comprises at least one connection portion , or bell, suitable for connecting the disc to a connection device, or journal, of the vehicle associable with the braking device ; and wherein said braking band defines an axial direction (X-X) parallel to the rotation axis (A-A) of the disc , a radial direction (R-R) orthogonal to the axial direction (X-X) and a tangential or circumferential direction (C-C) orthogonal both to the axial direction (X-X) and to the radial direction (R-R); and wherein said connection portion is connected to said braking band by means of connecting elements , said connecting elements are a plurality of elements which are equally spaced apart in circumferential direction (C-C); wherein - said connecting elements are firmly connected to said braking band so as to avoid a related movement between said connecting elements and said braking band during the operation of said braking device mounted on the vehicle; - said connection portion is bell-shaped and comprises a disc-shaped attachment flange having a flange outer edge and a cylindrical connecting casing which protrudes in axial direction (X-X) from the flange outer edge ; - said cylindrical connecting casing comprises through seats which freely slidingly house said connecting elements , thus allowing the braking band to expand radially (R-R) when thermally urged; characterised in that said plurality of connecting elements are a predefined prime number of seven connecting elements . and wherein said braking band defines an axial direction (X-X) parallel to the rotation axis (A-A) of the disc , a radial direction (R-R) orthogonal to the axial direction (X-X) and a tangential or circumferential direction (C-C) orthogonal both to the axial direction (X-X) and to the radial direction (R-R); and wherein said connection portion is connected to said braking band by means of connecting elements , said connecting elements are a plurality of elements which are equally spaced apart in circumferential direction (C-C); wherein - said connecting elements are firmly connected to said braking band so as to avoid a related movement between said connecting elements and said braking band during the operation of said braking device mounted on the vehicle; - said connection portion is bell-shaped and comprises a disc-shaped attachment flange having a flange outer edge and a cylindrical connecting casing which protrudes in axial direction (X-X) from the flange outer edge ; - said cylindrical connecting casing comprises through seats which freely slidingly house said connecting elements , thus allowing the braking band to expand radially (R-R) when thermally urged; - said connecting elements are firmly connected to said braking band so as to avoid a related movement between said connecting elements and said braking band during the operation of said braking device mounted on the vehicle; - said connection portion is bell-shaped and comprises a disc-shaped attachment flange having a flange outer edge and a cylindrical connecting casing which protrudes in axial direction (X-X) from the flange outer edge ; - said cylindrical connecting casing comprises through seats which freely slidingly house said connecting elements , thus allowing the braking band to expand radially (R-R) when thermally urged; characterised in that said plurality of connecting elements are a predefined prime number of seven connecting elements . <EOS>