I'd like to put in my 2 cents worth. I'm not an engineer, and don't know all the answers, and some of you have more bike experience than I have. But, speaking from a heavy equipment mechanic's experience (23 years) I'd like to remind some, and inform others, of the purpose of a lubricant on a bearing surface. The coating of oil or grease on a bearing, actually carries the load, and protects the metal bearing surface from abrasion. All bearings ride on a coating of oil. Metal-to-metal contact is very bad. How long would your internal combustion engine bearings last, if the force of the combustion stroke slammed the connecting rod bearings directly against the crankshaft journals? I guarantee you, it won't last very long.
This same action is taking place inside your chain rollers. Think of the force that your powerful legs are putting against a VERY tiny surface in each link. There must be a coating of oil on that surface. An oil that is very light, can actually be squeezed out. Products like WD-40, and penetrating oils, while very good for many applications, contain more solvent than oil. I think it's good for displacing water after a wet ride, and loosening the external dirt for a quick wipe-down, when you don't have the time to clean and oil the chain properly, but I'd get back to it, and properly clean and oil that chain as soon as I could.
Joe
