Originally Posted by
Sixty Fiver
"This is a common question and I will start by saying that WD40 is NOT a lubricant and should not be used on bicycle chains as it is primarily a solvent and will wash any lubricant out of your chain.
If you do neglect your chain and it starts to stick WD40 can be used to free stuck links but then a proper chain lube should be applied."
WD40 is a great chain and parts cleaner. After cleaning my chain with WD40 or gasoline (once a year), I'm using one of my favorite chain lubes - Prolink or T9. I also tried WD40 to clean my frame before winter. Frame stays cleaner longer and its easier to clean overall.
I don't recommend to use WD40 as a lube, but it makes a good "emergency" lube when there is nothing else to choose.