A rotor including: a shaft; a structure comprising at least one end ring and rotor bars, wherein at least the end ring comprises a material subject to expansion or movement radially outward from the shaft upon a rotor balancing process that involves spinning of the structure; a core that at least partially encloses the rotor bars; and means for limiting the expansion or movement of the structure radially outward. A method including: providing a structure comprising at least one end ring and rotor bars, wherein at least the end ring comprises a material subject to expansion or movement radially outward from the shaft upon spinning of the structure; assembling a rotor from the structure and a core, the core at least partially enclosing the rotor bars; spinning the rotor in a rotor balancing process; and limiting the expansion or movement of the structure radially outward in the rotor balancing process.