John Forrest Tomlinson wrote:
> On Sun, 22 Jan 2006 21:22:33 -0500, John Forrest Tomlinson
> <[email protected]> wrote:
>
>
> >Why do guys like Johnny Sunset talk about insignificant savings in
> >weight or aerodynamics but not insignificant increases in durability?
> >The odds of my wife's 28 spoke front wheel having problems are
> >remote. So Sunset has to mention that it will be less useful if some
> >heavy person needs it. Talk about grasping at straws.
>
>
> Should've been clearer. I meant, why do they relish pointing out the
> insignificance of small savings in weight or aerodynamics, while not
> also recognizing that some durability improvements are insignificant
> too?
Speaking for myself:
One difference in these "small savings" is the magnitude of the
consequences. That is, if a person is deciding between 36-spoke wheel
vs. a 28 (or fewer) spoke wheel, the negative consequence of the 36 is
they may require 0.002% more time to get to their desination. The
negative consequence of the lower spoke count wheel is they may not get
there at all without being chauffered in a car! IIRC, I detailed one
such case upthread, where I came upon a guy with fancy wheels stranded
on a deserted highway because of one broken spoke.
The advantage is similar with STI vs. competitors. Sure, it doesn't
happen frequently, but I've had two friends whose STI just absolutely
refused to shift, where the "time penalty" was hours (in one case) or
over a day (in the other) to get them working. To me, that's
absolutely unacceptable. And it happens frequently enough to deserve
"FAQ" status on r.b.tech.
I've got two titanium seat rails that I pass around in my classes as
perfect examples of fatigue failures. They were donated by a
weight-weeny friend. My steel rails have never failed - and I'm
heavier than he is. However much time he's saved by the lighter rails
has been more than obliterated by the necessity for replacing them.
None of this is dealing in absolutes. It's always a probability thing,
partly because the loads on most bike components are difficult to
quantify, partly because the duty to which parts are subjected varies
greatly from rider to rider.
Since you can't calculate this stuff precisely, much of the development
of bike parts has been trial and error. There's always some little
shop saying "Hey, we can shave 30 grams off that component and sell a
bunch to the racers." And the weight weenies buy it and try it, and
after three years of volunteer testing by the weight-weenie public, you
get to hear that it's not working out well.
Except when some design innovation _does_ work, of course, then it
becomes mainstream. The questions for me are a) Do I care to be an
early adopter, part of the "volunteers" who pay money to be the test
team so as to get the advantages first? and b) Are the advantages
likely to be worthwhile to me if and when it does work?
I've cycled long enough and happily enough that I'm not in desparate
need of any new develoment to keep me content. And my riding style, my
favorite rides, pay dividends for reliability, not speed. So even in
the case of 32 spoke wheels (instead of 36) I see no reason to change.
The trade in speed vs. reliability is probably small either way, but
the speed matters less to me than the reliabilty, so I'm just not
interested.
YMMV, obviously.
- Frank Krygowski