Motorcycle chain cleaning is an essential maintenance procedure on all chain-driven bikes. While everybody have their favorite chain cleaner, the topic of the suitability of WD-40 as a chain cleaner (and as a chain lube) is amongst the most controversial ones in chain maintenance chats. Some swear by it, while others swear at it.
The biggest concern motorcycle owners have on the choice of cleaning fluids on their o-ring (or x-ring, or z-ring) sealed chain is the effect of the fluid on the o-ring itself. The 0-rings serve as a seal that locks lubricating grease between the pin and the roller of the chain, significantly increase the chain’s useful life as compared to non-o-ring chains. Any deterioration of this rubber o-ring will allow grease to escape and contaminants such as dirt, mud and other yucky stuff into the tiny crevices inside the chain, leading to a drastically reduced chain life.
The idea that WD-40 reacts with rubber, swelling, softening and making it brittle has been debunked. MC Garage produced an excellent video to demonstrate this:
Still not convinced? Kiethm (nick: klm4755) also ran his pretty comprehensive home experiment on the effects of WD-40 (amongst other liquids) on chain o-rings, and posted it on advrider.com. Do check out his amazing effort there!
And the results?
“No visible impact to exposure, maintained shape and elasticity.”
Not bad, WD-40! You’re doing well!
And although WD-40 has been demonstrated to not affect rubber o-rings in the experiments above, some are still (rightfully) skeptical if it has any effects on the grease within the chain.
You see, WD-40 was designed as a water-displacement fluid. It is also a great penetrating fluid and it is reasonably concerning that if the WD-40 gets past the o-rings, what then are its effects on the grease within? Will it dissolve grease and thus dry out the inside of the chain?
And so I set out to perform a little experiment of my own. Now, I have to say that this is in NO WAY near completely scientific, but the goal was to convince MYSELF if WD-40 is safe for use on an o-ring motorcycle chain with sealed grease. So I mimicked Keithm’s experiement – but this time, with GREASE instead of o-rings.
And here’s the observation within the first 5-minutes of soaking:
I wasn’t expecting any observable changes to the grease blob soaked in water (D) and air (E). As expected, the grease blob exposed to degreaser (C) rapidly softened and appeared to “dissolve”. While there was no observable change to the WD-40 (A) mix, I was very surprised to see a very slight reaction the chain cleaner (B) had on the grease blob.
I then allowed the solutions to soak for the next 12hrs or so to determine what effects the various fluids have on the grease blob.
And 12 hours later…
Not surprisingly, no change to the water (D) and air (E) mixture.
And I thought I’d let the video explain the viscosity of the mixture.
Again, I’ll let the video do the talking:
But perhaps the most surprising of all is the WD-40 solution. The grease blob soaked in the WD-40 solution seem to hold up really, really well – especially when compared to the commercial chain cleaner (which I trust to have been tested to not harm to motorcycle chains.)
Again, the video here:
Summary of the observations in this table here:
So there you have it! WD-40 doesn’t swell o-rings. And even if WD-40 gets pass them and reaches the grease contained inside the chain, it doesn’t react with or dissolve grease (at least not any more than a commercial chain cleaner does.)
I don’t know about you, but I feel pretty confident using WD-40 as a chain CLEANER. It’s appears to be safe on o-ring chains and grease, and in my experience, does a great job cleaning off gunk too. It probably won’t function as well as a chain LUBE though – but that’s for another day. Of course, if you still feel uncomfortable, there is always the commercial chain cleaners that you can get off the shelves that are specifically designed to clean motorcycle chains.
But hey! Since there are so many other uses for WD-40 and not just chain cleaning, and at only a few dollars for a large can of WD-40, I know what I’d be keeping in my tools cabinet.