Hi- I make Chain-L, so take anything I say with a grain of salt.
The study in question was a bit flawed in a few respects, but their conclusions that lube makes little or difference in power loss, shouldn't totally surprise anyone.
All lubricants cost a bit in energy loss, based on their viscosity and the amount of surface area involved. Also most lubricants ability to lubricate at high loads is somewhat proportional to their viscosity, so in effect some of the benefit of lubrication will always be offset by the viscous drag.
This is particularly significant in bike chains because while the lube reduces friction in the pins, there is lots of shearing action in the lube in the space where the plates overlap and rotate with respect to each other. Depending on the tension load and the nature of the lube, it's quite possible that the viscous drag exceeds the gain in reduced friction.
That said, ask yourself how you'd like your lost power to happen - wearing metal away from the chain itself, or overcomming viscous drag in the lubricant.
The simple reality is that roller chain drives are amazingly efficient mechanical systems, at about 97%, and the role of chain oil isn't to improve on that, but to prevent wear of expensive parts.
FB
