WD-40 isn't, and is not intended to be, a lubricant
What the manufacturer says.
While the “W-D” in WD-40® stands for Water Displacement, WD-40® Multi-Use Product is a unique, special blend of lubricants. The product’s formulation also contains anti-corrosion agents and ingredients for penetration, water displacement and soil removal.
While WD-40® Multi-Use Product it is not a grease, it is formulated with strong lubricating oils and other ingredients, and is a terrific product to use for bike maintenance. It does not attract dirt or moisture to metal surfaces – just be sure to wipe off any excess WD-40® Multi-Use Product before riding.
For long-term lubrication and other specialized bicycle maintenance needs, check out WD-40® BIKE. Developed specifically for cyclists and mechanics, this high-performance line of bicycle care products is sure to become a mainstay in the toolboxes of bike mechanics for decades.
Due to its low viscosity, WD-40 is not always the preferred oil for certain tasks. Applications that require higher viscosity oils may use motor oils. Those requiring a mid-range oil could use honing oil.
Originally designed to be used by Convair to protect the outer skin and, more importantly, the paper-thin balloon tanks of the Atlas missile from rust and corrosion. These stainless steel fuel tanks were so fragile that when empty they had to be kept inflated with nitrogen to prevent them from collapsing. WD-40 was later found to have many household uses and was made available to consumers in San Diego in 1958.