"Jim, N2VX" <
[email protected]> wrote in message
news:<
[email protected]>...
> On 4 Nov 2003 19:19:44 -0800,
[email protected] (Carl Fogel) wrote:
>
> >"Jim, N2VX" <
[email protected]> wrote in message
> >news:<
[email protected]>...
> >> I recently switched chain lube from wax to the latest sheep dip named Dumonde. Of course after
> >> a couple weeks the chain was filthy.
> >>
> >> So I took it off and cleaned it using a solvent in a clear plastic bottle. After the first wash
> >> I put the used solvent aside for later disposal and repeated the process. It looked very dirty,
> >> no surprise there. Nothing sank to the bottom so the dirt wasn't sand or dirt.
> >>
> >> I looked a few hours later and it started to settle out. The dirt that I could see almost
> >> looked like little tiny fibers.
> >>
> >> The question: What is dirt made of? I don't ride offroad so it must be stuff picked up from the
> >> air. How abrasive is it?
> >>
> >> Thanks, Jim
> >
> >Dear Jim,
> >
> >It's dirt, for lack of a better word. Your front tire kicks it up in the form of dust as it rolls
> >along the dusty, dirty pavement. So does your rear tire, spinning next to the chain. The
> >turbulent air from two spoked wheels and your thrashing pedals and the air whooshing around your
> >legs and frame helps the dust storm.
> >
> >Your chain merrily rolls round and round in a microscopically filthy cloud. If it's oiled, the
> >minute crud sticks happily to the oil. If it's waxed, the stuff gets mashed into the wax. If it's
> >not lubricated with oil or wax, you're doomed anyway by dry metal-to-metal contact.
> >
> >How abrasive is this fdisgusting mess? Depends on your point of view. It eventually ruins all
> >chains, but they actually last a hell of a long time if you think about it. It's basically a very
> >fine polishing paste with a fair amount of tiny grit mixed into a lot of carrier.
> >
> >Clean and oil a chain and your gears, then run the chain through a paper towel, wipe the front
> >chain ring off, and set the clean but oily paper towel aside.
> >
> >Now ride fifteen miles on the nicest pavement that you can find and wipe the chain and front
> >chain ring down again with another paper towel. It will be black, having picked up dust.
> >
> >Off-road is worse. Much worse.
> >
> >The tiny fibers may in fact be tiny fibers--there's plenty of minutely shredded plant matter on
> >the pavement. Think of the fluffy dandelions and disintegrating leaves. The dust particles
> >themselves are too small to see with the naked eye.
> >
> >If "dirt" isn't a good enough description, try "silica," since a lot of it involves particles
> >ground off grains of sand, hard stuff that wears out the inner surfaces of chains.
> >
> >Carl Fogel
>
> Thanks to Chris and Carl for the replies.
>
> You are both right, I didn't think too hard about stuff kicked up by the wheels. Roads are always
> dusty and then there's plant-related fluff, too.
>
> It was funny how the dirt didn't settle out for some time. This time of year there's probably all
> sorts of pulverized plant material in the air.
>
> The other funny part is how fast a chain gets filthy. It doesn't take long.
>
> Jim
Dear Jim,
As for how long it took for the dirt to settle out, keep in mind how tiny the dust particles are.
A lot of what finally settled is what you can see floating in a beam of sunlight in an otherwise
dark room.
The PigPen-like speed at which chains get dirty is due to the oil--instead of most of the dust and
grime bouncing off a dry surface, every tiny bit of dust that hits an oiled surface is trapped like
an flea on flypaper.
This is why some people like wax instead of oil. They reason that the dry wax flakes off in tiny
layers, continually presenting clean surfaces, and doesn't even trap dust like oil in the first
place. Nor does wax carry outer but harmless grime into the out-of-sight working parts of the chain,
which oil tends to do.
Unfortunately, the inability of wax to flow in and out under varying pressure like oil is a serious
drawback in terms of lubrication. The inner surfaces of oiled chains pretty much stay oiled, but
with increasingly filthy oil. Once the wax has been squeezed, worn, flaked, or otherwise forced out
from between two metal surfaces, it's gone and they squeak and grind.
(This is a petrochemical abuser's quick summary of a perennial lubrication debate. Again, from a
practical point of view, chains last a hell of a long time, no matter how you maintain them, when
you remember the abuse that they endure.)
As always, you can get better information in the FAQ:
http://www.faqs.org/faqs/bicycles-faq/part3/
(chains start at 8d or so)
or at Sheldon Brown's web site:
http://www.sheldonbrown.com/glossary-c.html
(which is always worth wandering around in)
Time to clean my chain.
Carl Fogel
