I used hot melt candle wax on the chain of my first good road bike since new, for cleanliness. I was clueless at the time about checking for chain stretch. I ended up running the same chain for 15 years, my estimate is 70,000 miles. Then I noticed cupping on the cogs, so reversed them (could do that with Uniglide), and bought a new chain. Never ridden in rain.

In more recent years I had used oil lube, due to occasionally being caught in rain, and because I thought it would lube better. I never suspected that wax was actually better in terms of durability, until seeing test results on ZFC. My plan is to go back to wax this year.

The mechanism by which wax lubricates the chain, I am only guessing, is that it works sort of like old babbitt metal poured-in-place bearings; The wax creates a solid bushing, not as hard as the materials it separates, between the rollers and bushingless nubs, and between the inner plates and pins, and is not squeezed out, until worn away and the chain begins to squeak and is rewaxed. The wax on the outside of the chain flakes off very quickly, and I would think also in the flat area between outer and inner plates, though in a thread or website this year (can't recall which), someone had photo proof of wax with PTFE additive bonding durably to that sideplate interface. But in the two places mentioned, my guess is the wax is captured so does not just flake off. IF TRUE... I think a softer wax mix (wax with tallow, mineral oil, or as seen on Sheldon Brown, new toilet ring seals) would be inferior to a harder wax mix. Also, a harder wax seems to facilitate easily shedding of any fine metal particles, as well as dirt, whereas a softer wax may keep both embedded and act as abrasive. My current oil lube, when I clean with solvent, a magnet into the solvent removes copious amounts of black sludge, which is the very fine metal particles from the chain, which turns the oil lube into a paste due to the particles in suspension, that's my clue to clean and relube the chain. When I wax lubed, I never saw anything but the slightest amount of metal particles at the bottom of the wax pan, and I mean over a decade in the same pan of wax. So either way less metal particles created, or them being shed into the environment.

Does anyone else have a different theory about how/why melted hard wax lube works so well?