Originally Posted by
Sixty Fiver
There is a reason why every bike mechanic I know will tell you that WD40 is a poor chain lubricant, myself included.
Wet lubes attract dust so a lubed chain is going to get dirty and require periodic cleaning and this is the nature of chain drives... dry lubes are great if you live in places where it does not rain much and during the mid summer here, dry lube is great stuff.
If the drive is all shiny and clean because you are using WD40 it is because there isn't any lube there to pick up dust and dirt so of course it will stay cleaner.. I have a lot of people tell me that is why they were using WD40 in the first place... as I tell them they need to replace their prematurely worn chains (and drive components) and then explain why they need to use the proper lube.
I'm just a lowly mechanical engineer who's who's been riding bikes and wrenching on them for 25 years. I've been using homebrew wet lubes for the last 10 years and I get better chain life than 90% of those who post on this forum. My regular homebrew is a 4/1 mix of mineral spirits or naptha and synthetic motor oil. I used a Campy chain with that lube for 6,000 miles and measured 1/16" of elongation over the entire length of the chain - not 12 inches. That blows your theory that wet lubes attract dirt and cause premature wear. A Shimano or KMC won't perform that well, however. Shimano in particular, will elongate at least four times faster than a Campy chain, with the same lube.
The popular ProLink chain lube is nothing but a mineral spirits and oil wet lube. Most shops sell a 4-ounce bottle for $6-8. I can make the same thing for 8 cents.
I don't ride in the rain since it rarely rains here in the Denver area, but I never intentionally rode in the rain when I lived in the Kansas City area either. I do ride where it's dry and dusty, with plenty of grit for that wet lube to pick up.
WD-40 has about the same percentage of oil as my regular homebrew. I know that the oil isn't very heavy, but it really behaves about the same as my homebrew. I do relube my chains frequently and wipe them down before and after lubing. I suspect that the greater reason for premature chain wear in infrequent lubing. A factory rep from ProLink actually advised me NOT to relube unless the chain started squeaking. Just what I want, a chain that starts squeaking after 10 miles into a 50 mile ride. No thanks.
When I get done with my chain wear test and find little difference between WD-40 and 80/90W synthetic gear lube, will that change your mind?
FWIW, the lubrication expert who posts on this site doesn't have much good to say about dry lubes.