Steerer plug mount for fenders

The fork crown has no mounting points on my bike for a fender or anything else.

I didn't want to drill it, so I made a plug for it.

The plug uses an off-center M4 x 30 mm bolt to clamp a 45 deg wedge in the same style as a quill stem.

It works surprisingly well & holds in place securely, but hasn't been tested over a long time yet.

The plug carries a second M4 female thread as a mounting point. You can also use this to extract the plug assembly.

M4 is the only thread size that could reasonably fit given the limited ID I had to work with.

The steerer plug is designed for a drop in fit into a 19.2 mm ID steerer plug in a tapered aluminum steerer. You can adjust this parameter in the Solidworks file. It's also flanged to prevent it from falling into the steerer. The flange diameter is also modifiable.

Other steerers, namely steel ones, need less of a wall thickness for the same strength & may come in larger IDs permitting M5 hardware.