Oh for pity's sake. If you listen to everyone here, WD-40 will make your chain blow up. Bull*****.

Just don't use it as lube. WD is low-viscosity with a healthy dose of volatile solvents to let it 'carry' and penetrate deaply, then evaporate. So it's great to displace water and muck that gets deep inside chains and other stuff. The trick is to NOT think that the oils left are any more than very light and insufficient mineral oil. Spray the crap out of it to clean it; but then blow all the WD-40 reside out with your air compressor - - THEN lube the chain with a good bicycle roller chain lube.

People make things so much more complicated and voodoo than they need to, These are bicycles . . . with roller chains (and comparatively low-grade ones at that). They're not 32-valve F1 cars, for pity's sake.