Re: Chain lube and rust
WD-40 was developed by the military in the 50s as a rust preventative solvent and de-greaser to protect missile parts. It quickly became a household item when people discovered it had thousands of other uses as a cleaner, rust-prevention agent, squeak-stopper and more. It also works wonders as a light lubricant on small items like hinges, locks, and toys. Bicycle chains, on the other hand, are far too heavy and fast-moving for the lubricating power of WD-40 to have any effect at all. As a matter of fact, WD-40 will actually strip away any existing lubricant and leave your drivetrain dry – metal on metal. Basically, spraying this stuff on your chain is worse than using no lubricant at all!
An alternative approach to chain lubrication is to immerse the chain in hot wax. This is a variation on the oil/solvent approach. The hot wax is of a thin enough consistency that it can theoretically penetrate into the private parts of the chain, then when it cools off, you have a nice thick lubricant in place where it can do the most good. The major advantage to this approach is that, once cooled off, the wax is not sticky, and doesn't attract dirt to the outside of the chain as readily. Downsides of the wax approach include the fact that it is a great deal of trouble, and that wax is probably not as good a lubricant as oil or grease.