Input and advice needed...
I'm researching an old steel framed bike that
I may purchase and ran across a touring oriented
comment in the Classic Rendezvous archives that
just doesn't jive with my understanding of things.
Somebody asked (in 2002) about about using a 1983 Trek 311
for touring and another poster made the following
> flexible rear end that doesn't handle too well when
> heavily loaded.
couple of points but was wondering if anybody
could deny or confirm that observation.
Here is my understanding of things:
TUBES - My understanding is that steel tubes'
stiffness is determined by the outer diameter
and thickness/butting, not on the different recipies
of steel (which effect strength and brazing).
Further, in that era, Trek primarily used Ishiwata
022 and Mangy X and Reynold 531 and 501 in their
touring and sport bikes and those tube sets were/are
pretty much the same in terms of thicknes/butting and
So, I conclude that this wobbly rear triangle observation
probably doesn't come doesn't come from material selection.
GEOMETRY - The big difference in the rear triangle is
chainstay length and Sport and Touring Treks of that era
ranged in the 43cm to 47cm range, compared to things in
the 41cm range for road bikes. While a longer chain
stay would presumably make for more bottom bracket
sway, I thought the common wisdom for touring was
longer was better for chainstays for increased comfort,
heel clearance and stability. I'm not sure wobbly
can be equated with bottom bracket sway so I totally
don't get what somebody would mean about a sport
frame being wobbly in this regard, especially when
the touring ideal is even longer!
Am I missing something here? My belief has been
that wobble and speed shimmy are related to panniers,
racks and load distributions (assuming a relatively
long rake). Could somebody defend this guy's
assertion or should I just dismiss it
Ding, ding, ding! Some of the Trek sport bikes had
relatively (for the day) steep steering angles in the
73.5 to 74 degree range and relatively short (for the
day) fork rakes of 4cm. I've felt bikes with tight
rakes get speed shimmy, especially with load up
high on the rear rack. Did I just answer my own
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Aristotle, <<Politics>>, 1323a-b, trans Jowett