Bike tail light adapter for Cat Eye B-1 rear reflector bracket

thingiverse

The Cat Eye B-1 rear reflector bracket attaches to the frame cross brace right behind the saddle post. It is considered a "vintage" part, and can easily be found on eBay. It is used to mount the Cat Eye RR-290 reflector, which is still sold by Cat Eye – although the bracket is no longer sold.This adapter lets you mount a saddle-post taillight on the reflector bracket.I made this because I wanted to mount a taillight on my old Nashbar road bike, but I have a tool bag occupying the position under the saddle, so I couldn't put a tail light there.The adapter prints as a vertical cylinder but the slot that surrounds the bracket is angled at 73°, which is the typical angle of a bicycle saddle post. The adapter is screwed in place with the original self-tapping screw from the reflector.PrintingThe only critical setting is the number of perimeters. Use 4 perimeters to cover the bite of the self-tapping screw threads.AssemblySlide the adapter onto the bracket, so that the slope of the adapter would be parallel to the saddle post.The screw is inserted from the forward-facing side of the adapter, opposite the rear side where the taillight would go.You need to exert a lot of pressure on the screwdriver to get the threads started.Don't over-tighten. The screw does not need to be tight, just snug. Its only purpose is to lock the adapter in place to prevent it from slipping off.