I wanted my bike computer to be centered above the handlebar. The design is slightly raised, to allow for something like a handlebar basket to also be in place. Initially I wanted an “invisible” floating design, but it wasn't stable enough. So now it's only somewhat invisibly floating. The handlebar part already clips on quite tight, but also has an internal channel for a zip tie, which mounts it quite firm.

I've been using it for some time now, and my first few prints broke due to the vibration. But I think I have it working reasonably well now. My guess is, PETG or ASA should be the best filament for it (pictured is Black ASA, my last one was PETG, broke in one place but still held on tight). Print with very high infill and 3+ walls, otherwise the arms might break off. Print two, mounted each on one side, the original mounting frame of the computer can then be screwed on.

The design is parametric to allow thicker/thinner handlebars, different screw layouts or larger/smaller distances between the mirrored mounts. Its created in OnShape: Link.