Patent ID: 7780558

Claim:
A bicycle rear derailleur comprising: a mounting member including a bracket having a fastening part that is configured to be fastened to a bicycle frame and a supporting part disposed rearward of the fastening part when the fastening part is fastened to the bicycle frame; a base member rotatably mounted on the supporting part to rotating about a first center pivot axis; a moving mechanism movably connected at a first end to the base member to move with respect to the base member; a movable member connected to a second end of the moving mechanism; and a chain guide including a first plate member pivotally connected to the movable member to swing about a second center pivot axis, a second plate member connected to the first plate member to define a chain receiving gap between the first and second plate members, a guide pulley rotatably supported between the first and second plate members at first ends of the first and second plate members, a tension pulley rotatably supported between the first and second plate members at second ends of the first and second plate members, and a chain slip prevention part disposed between the first and second plate members in a vicinity of the guide pulley with the chain slip prevention part having a width of 10 mm or greater and 50 mm or less, the chain slip prevention part including a first end part and a second end part, the first end part being a farthest point of the chain slip prevention part from the tension pulley as measured in a first direction that is parallel to a first straight line running between rotational centers of the guide pulley and the tension pulley with the first end point being located at one circumferential end point of the chain slip prevention part along a circumferential direction about the rotational center of the guide pulley, the second end part being a closest point of the chain slip prevention part to the tension pulley as measured in the first direction that is parallel to the first straight line running between the rotational centers of the guide pulley and the tension pulley with the second end part being located at the other circumferential end point of the chain slip prevention part along the circumferential direction about the rotational center of the guide pulley, the first end part being disposed closer to the rotational center of the guide pulley than the second end part, and the fastening part including a shaft member that has a third center pivot axis, with a minimum distance from the first center pivot axis to the chain slip prevention part being greater than a minimum distance from the third center pivot axis to the chain slip prevention part when the bracket is fastened to the bicycle frame.