[ST] Rear huggers and chain length explained

["Nowak, Nick" <n.nowak@xxxxxxxxxxxxxx>]

I started thinking(never a good thing) about the problems people are having
with fitting the rear hugger in combination with smaller front sprockets.  I
worked through a couple of calculations and a few autocad sketches, and this
is what I found - 

108 links of new 530 chain = 67.5 inches (5/8 pitch X 108)
The closest the rear wheel would be to the front sprocket with this length
is roughly 24 inches center to center.
Keeping the same center points for the front sprocket and rear wheel, these
are the following lengths of chain needed

17 X 43	=	66.89"
18 X 43	=	67.17"
19 X 43	=	67.50"
18 X 45	=	68.14"

To make it around a 17t vs. a 19t, you only need 0.61" less chain.  By going
down to 106 links, you would be removing 1.25" of chain.  If you could
remove half a link, then it would almost be perfect.  The simplest way to
explain this is by assuming the chain only runs across half of the front
sprocket.  In a 19t, the chain would be in contact with roughly 9.5 teeth.
In a 17t, the chain would be in contact with 8.5 teeth, thus there is only
about a one link difference between the two.  Also, the change in rear axle
position would only be approximately half of the difference between the
stock length and the new length listed above.

The point to all of this?  You should probably be using 108 links of chain
no matter which of the above sprocket combinations you are using.

Hope this helps
Nick "the dirtbag"
'00 Yellow RS 

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