A little nail polish on every bolt thread acts like a mild LocTite. My chain guard rattled for months until I finally spent a few hours scrubbing, tightening, rotating, and now every nut and bolt on Rocinante has a dab of nail polish.

All those little squeaks and rattles disappeared, leaving only the occasional and quirky "thunks", like the one on my front which has nothing to do with rotation or speed, that have been a mystery for a year.