Rear Brake Nutted Bolt to Recessed Nut Adapter

thingiverse

To convert a side-pull brake to a dual-pivot brake system, you'll need to widen the mounting hole in your frame from 6 to 8 mm to make room for the recessed nut. Unfortunately, the rear triangle often leaves little space to insert a drill and expand the mounting hole on that side. To solve this problem, this adapter is designed to let you widen the 6 mm mounting hole from the other side of the frame, expanding both sides to 8 mm. Once the expansion is complete, one of the holes is reduced back down to 6 mm. The system has been thoroughly tested and works perfectly, as shown in the accompanying photos.