Derailleur for a bicycle

A derailleur for a bicycle, for shifting a driving chain from one sprocket to another of a multistage sprocket assembly, said derailleur comprising:

• a linkage mechanism comprising a base member, an inner linkage member, an outer linkage member, and a movable member carrying a chain guide;
• and
• a connecting means comprising a pair of first connecting pins for respectively pivotally supporting one end of each of said inner linkage member and said outer linkage member to said base member and a pair of second connecting pins for respectively pivotally supporting said movable member to the other end of each of said inner linkage member and said outer linkage member, said first and second connecting pins being oriented obliquely with respect to a predetermined plane adapted to be positioned perpendicular to an axis of said multistage sprocket assembly when said derailleur is mounted on said bicycle, said chain guide, responsive to deformation of said linkage mechanism, being movable axially and radially of said multistage sprocket assembly when said derailleur is mounted on said bicycle;
• said inner linkage member having an upper surface at its said one end connected to said base member which is positioned at a predetermined position adapted to be located on a side closer to said axis of said multistage sprocket assembly relative to a phantom extension line extending from an upper surface of said outer linkage member at its said one end connected to said base member and perpendicular to an axis of the one of said first connecting pins which connects said outer linkage member to said base member.