Bike Rear Reflector Mudguard

Motivation

I wanted a mudguard similar to my previous design which didn't require as much specialized hardware to assemble. I had a spare rear reflector and felt that it had a reasonable solution for mounting to the seatpost, so I designed this mudguard to mount with the rear reflector hardware, and some additional common M3 hardware (and optionally superglue).

Important Note: This is not intended to replace a rear reflector, it is simply a way to reuse reflector hardware for a mudguard. Follow your local laws and use reflectors and lights when required.

Details

Assembly requires:

• 2x M3x8 screws
• 2x M3 nuts (or preferably, lock nuts)
• Rear reflector mounting hardware
• Highly recommended: Superglue

Note: It seems like there are a few different designs for rear reflectors, but mine came with 2 holes available for attaching the mudguard to and a screw that self-taps into the plastic reflector body. As long as you have the kind with 2 holes, you should be able to either superglue and zip tie the parts together, or use your own hardware to fix the mudguard to the reflector.

The diameter of the hole in the arm is 4.35mm. You can potentially drill this out if you are using ABS-like materials, but I would not recommend this with PLA. You can try to adjust hole size in PrusaSlicer by merging cylinder geometries (Add Part/Negative Volume). Note that while this is not very precise, the tolerances of the reflector hardware itself are not very tight, so you will probably be fine.

The mudguard is quite the cantilever on the reflector hardware, but I have found it to actually be quite resilient, though a bit floppy. I also recommend adjusting the angle of the flap with respect to the arm, then supergluing it in place, as otherwise it may droop down over time. I haven't ridden a large number of miles yet with this, and I usually use this on a bike with a rear rack, so the droop hasn't been much of an issue.

Printing Tips

• I recommend printing these in something like ABS or PETG for their superior mechanical properties compared to PLA, but PLA is not a bad option for this design. 
• If you are using self-tapping screws, I recommend using a modifier in the slicer to increase the number of perimeters around the hole. You can also print with extra perimeters on the whole part, but that will affect the weight and may overload the reflector hardware.
• The parts are quite long, but I am just about able to fit them on my Prusa i3 mk3s with some precise positioning.
• These parts aren't difficult to print by design, but take care that the overhangs from the nut slots print well, otherwise the nuts may not seat well and can cause the layers to split.