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From: peters@cubsvax.UUCP (Peter S. Shenkin)
Newsgroups: net.bicycle
Subject: Extent of Stretch of a Chain
Message-ID: <407@cubsvax.UUCP>
Date: Tue, 21-Jan-86 14:26:56 EST
Article-I.D.: cubsvax.407
Posted: Tue Jan 21 14:26:56 1986
Date-Received: Fri, 24-Jan-86 08:27:09 EST
Reply-To: peters@cubsvax.UUCP (Peter S. Shenkin)
Organization: Columbia Univ. Bio. CG Fac., NY
Lines: 28

I just replaced my chain, after finding that it still felt gritty after
cleaning (that is, it felt like there was grit in the bearings).  I had
hung my old chain up to dry, and instead of counting links, I hung my 
new chain beside it, expecting to be able to match ends, and therefore
not have to count links.  I was amazed to see that after lining the chains
up carefully at the top, the new chain was noticibly shorter than the 
old one even a foot down.  In fact, in 40 inches of length, the new chain
was shorter by a full link spacing, i.e., 3/4 in.  This comes out to
(3/4)/40=0.019, or 1.9%.  That doesn't sound like a big percentage, but
consider that 40in of chain has about 53 links in it, so it will approximately
fill a 52-tooth chainwheel a full circle around.   A chain stretched by 2%
is stretched roughly to the point that 51 links, instead of 52, fit around
such a chainwheel.  I haven't gotten back on my bike yet, but it'll be
interesting to see whether I can still shift, or whether I have to replace 
chainwheels and/or cogs.  Incidentally, the chain had less than 1000mi on it,
but much of my riding was fully loaded in sandy land.

My old chain was a DID-Lanier and the new one is a Sedisport, but this
shouldn't matter.

By the way, when I bought the new chain I also decided to invest in a Vetta
chain cleaner.  Live and learn.  And while I was at the shop, I picked
up a pair of the new Diadoro touring shoes;  haven't used them yet, but
they're beautiful, and very comfy.  (My old shoes literally fell apart
on my Florida trip.)

Cheers,	Peter S. Shenkin, Columbia Univ. Biol. Sci.
	philabs!cubsvax!peters		cubsvax!peters@columbia.ARPA