A disc assembly for disc brake comprising: - a brake rotor having a predefined rotational axis (A-A); said brake rotor having a disc-shaped brake body; said disc-shaped brake body comprising a brake disc attachment portion to a brake disc support having an attachment portion rest surface suitable to abut against said brake disc support; said brake disc attachment portion comprises securing means receiving seats suitable to receive securing means of the brake rotor to a brake disc support thereof; said disc-shaped brake body comprising a braking portion forming a braking band having opposite first and second braking surfaces (8, 9); said first and second braking surfaces (8, 9) being substantially mutually parallel and defining therebetween, under unworn conditions, a braking band thickness; wherein said rest surface of the brake disc attachment portion being, under unworn conditions, substantially coplanar to said first braking surface; - an excitation ring or pulse generating ring or phonic wheel having a predefined rotational axis (A-A); said phonic wheel having a phonic wheel disc-shaped body comprising a facing surface; said facing surface being suitable to face a sensor; said facing surface comprises a plurality of recesses or reliefs evenly distributed circumferentially and suitable to face said sensor; - a phonic wheel reading sensor to detect the rotation, or derived signals, of the phonic wheel; - securing means of the brake rotor to the brake disc support thereof; and wherein - said disc-shaped brake body and said phonic wheel disc-shaped body are in a single piece; - said securing means receiving seats comprise embedding widenings suitable to receive by embedding portions of the securing means so that they do not project relative to the brake disc attachment portion and wherein said embedding widenings are arranged on the same side of the surface facing the sensor of the phonic wheel disc-shaped body, so that said securing means are inserted in said receiving seats on the same side of the phonic wheel reading sensor; and wherein said facing surface comprises a plurality of recesses or reliefs evenly distributed circumferentially and suitable to face said sensor; characterized in that said recesses or reliefs are through holes; said phonic wheel is arranged radially with respect to the rotational axis between said brake disc attachment portion and said braking portion forming the braking band. - a brake rotor having a predefined rotational axis (A-A); said brake rotor having a disc-shaped brake body; said disc-shaped brake body comprising a brake disc attachment portion to a brake disc support having an attachment portion rest surface suitable to abut against said brake disc support; said brake disc attachment portion comprises securing means receiving seats suitable to receive securing means of the brake rotor to a brake disc support thereof; said disc-shaped brake body comprising a braking portion forming a braking band having opposite first and second braking surfaces (8, 9); said first and second braking surfaces (8, 9) being substantially mutually parallel and defining therebetween, under unworn conditions, a braking band thickness; wherein said rest surface of the brake disc attachment portion being, under unworn conditions, substantially coplanar to said first braking surface; - an excitation ring or pulse generating ring or phonic wheel having a predefined rotational axis (A-A); said phonic wheel having a phonic wheel disc-shaped body comprising a facing surface; said facing surface being suitable to face a sensor; said facing surface comprises a plurality of recesses or reliefs evenly distributed circumferentially and suitable to face said sensor; - a phonic wheel reading sensor to detect the rotation, or derived signals, of the phonic wheel; - securing means of the brake rotor to the brake disc support thereof; and wherein - said disc-shaped brake body and said phonic wheel disc-shaped body are in a single piece; - said securing means receiving seats comprise embedding widenings suitable to receive by embedding portions of the securing means so that they do not project relative to the brake disc attachment portion and wherein said embedding widenings are arranged on the same side of the surface facing the sensor of the phonic wheel disc-shaped body, so that said securing means are inserted in said receiving seats on the same side of the phonic wheel reading sensor; and wherein said facing surface comprises a plurality of recesses or reliefs evenly distributed circumferentially and suitable to face said sensor; characterized in that said recesses or reliefs are through holes; said phonic wheel is arranged radially with respect to the rotational axis between said brake disc attachment portion and said braking portion forming the braking band.