Front derailleur adapter (braze on)

thingiverse

This is a custom adapter to mount a braze-on front derailleur on a Mongoose Malus Fat bike. The Mongoose Malus comes with a single sprocket front, so I wanted to assemble a triple setup. With a bottom bracket size around 112 mm, I had to offset the deraileur and cable stay as well. There are four parts here, joined into two separate assemblies, each assembly clamps onto the seat tube individually. The cable stay has a spacer to keep it from moving up the tube if the cable force is high. Printing these two assemblies makes printing much simpler and allows for rotating the cable guide if needed. I printed mine in PLA at 40% infill density, which seems strong enough for my casual riding style, but you could print with nylon or a higher fill density for added strength. Required Materials: Four 6mm bolts and nuts Two 3mm steel rods (20mm long) or bolts I used this adapter with a Shimano Sora braze-on derailleur. Printer Settings: - Printer: Geeetech G2 - Rafts: None - Supports: Yes - Resolution: .3mm - Infill: 40% Post-printing steps: 1. Print one cable guide, two cable guides, and one derailleur adapter. 2. The extra cable guide piece will fit with the derailleur adapter. 3. Post-processing involves trimming the hinge sections using a sharp knife after removing supports so that pieces just fit together. 4. Drill out the center to fit your 3mm rod or use a larger hole and a 4mm bolt instead. 5. You'll need to drill a hole (or modify the STL) for the derailleur bolt. As you can see, the cable is coming out of the cable guide piece, and how the derailleur fits into the printed adapter. You can also see here the hinges in the two assemblies as well as the bolt holding the derailleur into the printed adapter.