A rear derailleur with an articulated quadrilateral linkage movable body along respective parallel articulation axes perpendicular to a reference plane (REF), a base body on a bicycle frame along a drop-out axis (F), a chain guide being rotatable around a first rotation axis (R), an upper pulley rotatable around a second rotation axis (RS). The first rotation axis (R) and the second rotation axis (RS) are parallel and spaced by a distance of eccentricity (E). An angle of inclination (Q) of the articulated quadrilateral is defined by the angle that the drop-out axis (F) and the reference plane (REF) form on a plane passing through the drop-out axis (F) and perpendicular to the reference plane (REF). The angle of inclination (Q) being between 5° and 40°, including extreme values, and the distance of eccentricity (E) being between 18 mm and 50 mm, including extreme values.