What are the differences between manufacturing a gearbox and conventional frame?
This question is asked because of the worry that manufacturing a gearbox frame would take much more time and effort to produce in comparison to a conventional gear hanger frame. The first difference of manufacturing a frame with a gearbox in comparison to a frame with a conventional gear hanger is the area around the bottom bracket. In comparison the mounting points between the frame and bottom Weldin/bracket on the gearbox frame are higher along the tubes. Responding to this the Weldin is simply a different shape to accommodate the mounting points and gearbox. Therefore the manufacturing processes equate to the same time and effort. When an aluminium-made frame is manufactured, first, the bottom bracket housing without thread is welded to the tubes of the frame. The drilled hole of the bottom bracket housing is smaller than the final diameter. This is to prevent the welding from destroying the bottom bracket housing thread. Therefore, only after the following heat treatment, the housi
