On 11 Jun 2004 02:32:23 GMT,
[email protected] (TBGibb) wrote:
>In article <[email protected]>, [email protected]
>writes:
>
>>The report mentioned may not have been quite as definitive
>>as everyone would like.
>
>Why not? And, will you commit yourself with more than a "may not"?
>
>I'll be glad to re-post my results.
>
>I started that trial because of the authoritative "oil on a chain that hasn't
>been completely cleaned will produce a grinding paste inside the chain"
>statement here on the news group that was contradicted by SRAM's web site where
>they advocated simply cleaning the outside using some kind of degreaser. My
>first thought was the SRAM was trying to sell chains by recomending substandard
>cleaning. So I started the trial with the presupposition that SRAM was wrong.
>Knowing that I might (!) be biased in the measuring of the chain I drafted my
>wife to confirm my measurements. In the end there was no doubt for either of
>us, the "solvent thrashed" half elongated to the 1/16 mark before the wiped and
>brushed half. There were a few times before the chain got to that point that
>our 33 year old marriage was slightly stressed because I was sure the solvent
>method was going to be the best. It's pretty easy to be off when the ruler is
>measuring to 1/32 and both of us are not close focusing as well as we used to.
>But in the end there was no question as we can both easily detect 1/16. And, I
>had to admit I was wrong.
>
>I encourage anyone that doubts my results to try it themselves and publish
>their results. It's not hard but it does take a little time. I especially
>would like to see this done in a rainy climate as this one is dry and in a
>drought.
>
>Tom Gibb <[email protected]>
Dear Tom,
Here's a link to a post from DVT in the middle of your
original thread about your chain testing:
http://groups.google.com/groups?q=c...&[email protected]&rnum=2
In any case, DVT's "chainge" pun deserves notice.
For anyone interested in browsing the 61 posts, the page in
Google Groups offers the option to view-complete-thread.
I think that the posts support the comment that the test may
not be as definitive as everyone would like.
Briefly, you used a pair of master links to connect two
chain sections, one of which you cleaned by washing nine
times in about 2700 miles, measuring chain wear in 1/64ths
of an inch. (I won't try to recount the details of exactly
how things were washed, brushed, re-oiled, and so
forth--they're in the thread.)
Curiously, the first six pairs of measurements show that the
unwashed chain section wore noticeably faster than the
washed chain:
> Date Miles Elongation Elongation
> of washed of unwashed
> chain chain
> 07/11/03 0
>
> 07/14/03 137.1 0 0
> 07/23/03 328.6 1/64 1/64
> 08/01/03 607.24 1/64 1/64
> 08/11/03 819.71 1/64 1/64
> 09/02/03 1076.67 1/64 1/32
> 09/19/03 1430.39 1/64 1/32
Apparently, washing reduced chain wear for the first 1430
miles. The repeatedly washed chain is stubbornly showing
only 1/64th of an inch of elongation, just half as much as
the unwashed chain.
But this trend abruptly reverses in the next 370 miles after
a single washing:
> 10/23/03 1801.17 3/64 1/32
Why did the washed chain elongate twice as much in 370 miles
as it did in the previous 1430 miles? It doesn't seem to
have been a terribly abrasive period, since the unwashed
chain shows no measured wear at all during the same time.
The sudden accelerated wear disappears with the next
washing--the washed chain doesn't wear noticeably in the
next 456 miles:
> 11/07/03 2257.55 3/64 1/32
Then it wears a little in the next 484 miles:
> 01/05/04 2739.52 1/16 1/32
What the measurements seem to show is an impressive hiccup
between 1430 and 1801 miles, as if whatever was done to the
washed chain at 1430 miles tripled its wear rate--which then
returned to normal after the next washing.
It could be that the big blip in the wear rate accurately
reflects something odd in the chain-washing at 1430 miles.
It could be that the big blip in the wear rate shows that
chains wear oddly, with a sudden increase in wear as some
surface is worn away, followed by a slow-down as yet another
surface is exposed.
It could be that the tiny measurements are so tricky that
normal variation and error are responsible for what looks
like an odd pattern. After all, measuring chains to within
1/64th of an inch is the kind of exercise that high school
science teachers use to show students just how hard
seemingly simple experiments are in real life.
It could be other things, too, but the tripled wear-rate in
the 370 miles between the sixth and seventh chain washes
suggests that the extremely small measurements and slow wear
rates involved in chain-care experiments may require more
than a single test to be definitive.
Cheers,
Carl Fogel
