WD-40 as lubricant

Never use WD-40 to lubricate your drivetrain.

WD-40 is meant for rust-prevention. It's a 'squeak-stopper'. It is also a degreaser as well as water repellent. It's a wonderful household item. It may be used as cleaner or 'light' lubricant for door hinges, locks, toys but not bicycle drivetrain especially the chain.

The fast-moving bicycle chain will strip away lubricant and leave the chain dry. This is bad!

Instead, use suitable lubricant that is specially made for bicycle like the one from Finish Line, White Lightning, Pedros, etc, to lubricate your drivetrain. They are heavy duty, also water-proof and great for your chain.

For degrease purpose, I personally use citrus degreaser because they did a great job & safe to use. If I am to use the WD-40 as degreaser, I will wipe it off clean before applying the lubricant. This is to prevent it from striping away the lube after applying it.