Abstract: A bicycle frame includes two first through holes respectively defined in two opposed points in a periphery of the head tube to communicate with the down tube so as to allow extension of a first derailleur cable for a front derailleur and a second derailleur cable for a rear derailleur. The bottom bracket has a down tube hole for communication with an interior of the down tube, two chain stay holes for communication with each of the two chain stays and two bellow tube holes for extension of two a first bellow tube and a second bellow tube respectively received in the bottom bracket. The derailleur cables extend to the first bellow tubes and the second bellow tubes respectively, which in turn extend out of the bottom bracket and toward the extension holes of the inner tubes for connection to the front and rear derailleurs.

Abstract: A bicycle frame includes two first through holes respectively defined in two opposed points in a periphery of the head tube to communicate with the down tube so as to allow extension of a first derailleur cable for a front derailleur and a second derailleur cable for a rear derailleur. The bottom bracket has a down tube hole for communication with an interior of the down tube, two chain stay holes for communication with each of the two chain stays and two bellow tube holes for extension of two a first bellow tube and a second bellow tube respectively received in the bottom bracket. The derailleur cables extend to the first bellow tubes and the second bellow tubes respectively, which in turn extend out of the bottom bracket and toward the extension holes of the inner tubes for connection to the front and rear derailleurs.