The present invention relates to a device for demounting a tire (T) from a rim (W), comprising: at least one support element (3, 5); an articulation pin element (9; 29) borne by the at least one support element (5); a spring shackle element (7; 70) having a first end (7a) and a second end (7b) articulated on the articulation pin (9; 29); a demounting lever (2); an actuator (4) borne by the at least one support element (3) and set to act on the demounting lever (2) in order to make the demounting lever (2) angularly move during use; and friction or elastic loading means designed to slow the angular movement of the spring shackle element (7, 70) around the articulation pin (9, 29) with respect to its angular movement around the first axis (x-x).