A rotation detection set comprising: - an encoder washer rotatable around a rotation axis (X2, X20), - at least one sensor (48A-48D) adapted to detect a rotation parameter of said encoder washer through an air gap, - a support member for holding said sensor with respect to said rotation axis (X2, X20), - a mounting member for immobilizing said support member with respect to a fixed structure, wherein - said mounting member is made of one piece of magnetic material - said detection set includes several sensors (48A-48D) - said mounting member is an annular flange centered on a central axis superimposed with said rotation axis (X2, X20) in a mounted configuration of said rotation detection set and has a first peripheral wall located on the same side of said air gap as said encoder washer and a second peripheral wall located on the same side of said air gap as said sensor (48A-48D) - said first and said second peripheral walls (421, 423) are parallel to said central axis - a magnetic body of said encoder washer, said air gap and respective bodies of said several sensors (48A-48D) are located in a volume (V 42) defined by said mounting member between said first and second peripheral walls (421, 423) - a third wall of said mounting member connects said first and second walls (421, 423) and is perpendicular to said first and second walls characterized in that - said first peripheral wall is an inner radial wall of said annular flange, - said second peripheral wall is an outer radial wall of said annular flange, - along an axis radial with respect to said rotation axis (X2, X20) in the mounted configuration of said rotation detection set, said magnetic body is located between said air gap and said first inner radial peripheral wall and a body of said sensor (48A-48D) is located between said air gap and said second outer radial peripheral wall - said third wall is provided with a hole for the connection of said sensors to an electronic device, - said support member has an extension engaged within said hole and defining a housing (V 445) where all said sensors (48A-48D) are accommodated. - an encoder washer rotatable around a rotation axis (X2, X20), - at least one sensor (48A-48D) adapted to detect a rotation parameter of said encoder washer through an air gap, - a support member for holding said sensor with respect to said rotation axis (X2, X20), - a mounting member for immobilizing said support member with respect to a fixed structure, - said mounting member is made of one piece of magnetic material - said detection set includes several sensors (48A-48D) - said mounting member is an annular flange centered on a central axis superimposed with said rotation axis (X2, X20) in a mounted configuration of said rotation detection set and has a first peripheral wall located on the same side of said air gap as said encoder washer and a second peripheral wall located on the same side of said air gap as said sensor (48A-48D) - said first and said second peripheral walls (421, 423) are parallel to said central axis - a magnetic body of said encoder washer, said air gap and respective bodies of said several sensors (48A-48D) are located in a volume (V 42) defined by said mounting member between said first and second peripheral walls (421, 423) - a third wall of said mounting member connects said first and second walls (421, 423) and is perpendicular to said first and second walls - said first peripheral wall is an inner radial wall of said annular flange, - said second peripheral wall is an outer radial wall of said annular flange, - along an axis radial with respect to said rotation axis (X2, X20) in the mounted configuration of said rotation detection set, said magnetic body is located between said air gap and said first inner radial peripheral wall and a body of said sensor (48A-48D) is located between said air gap and said second outer radial peripheral wall - said third wall is provided with a hole for the connection of said sensors to an electronic device, - said support member has an extension engaged within said hole and defining a housing (V 445) where all said sensors (48A-48D) are accommodated.