Bruce Schrader wrote:
>
(cut)
> By "sighting" from behind the rear cluster up through
> the chainwheels, I can move my head left or right so
> that I'm viewing a straight line that the chainwheel
> will take and see which rear gear it lines up with.
> Ideally, in a triple crank/7sp cluster, the chain
> wheel that I sight on is the center one and the line
> it should take is through the center gear on the
> cluster (three on either side of the center one). If
> your eye sight is not that good, then a piece of
> string tied to a tooth on the front side of the
> chainwheel, running along side the chainwheel and back
> to the cluster will show where the chain line goes.(cut)
There is a Campagnolo tool ("G") for this job. Its a metal straight edge that nestles between the large and small chainrings and extends backwards to the freewheel. The straight edge should pass over the middle cog on a five speed freewheel and split the third and fourth cog on a six speed.
I find that a common yard stick is a perfect substitute for the Campagnolo G tool.
Chuck Schmidt SoPas, SoCal http://www.velo-retro.com (Catalogo Campagnolo 1951-1984)
.