Jasper Janssen said:Quoted message said:Quoted message said:I've actually read and thought about this a bit and am not
convinced that it's actually qualifies as an upgrade.
Quoted message said:Quoted message said:I'm with Eric. And there's no shortage of black quills. If
anything there's more selection now, especially at both small and
large extremes.
Quoted message said:Yeah, me too. The main advantage of threadless, besides giving bike
shops something to do in selling them for older bikes and the
immense market in replacement stems, seems to be that you don't get
aluminum quills oxidizing solid in the steerer tube any more. Now,
if I had my druthers, I'd call that a materials science defect
rather than a structural defect. Never seen an old fashioned
chromed-steel stem be more than a little rusted shut.
I think you must have missed the years after the introduction of the
aluminum quill stem when steel stems practically vanished. Head
bearing manufacturers tried O-rings in the top nut and goop in the top
of the steer tube to prevent the common permanent corrosion of stem to
fork.
Only then did the failure mode become apparent in which the quill stem
is attached only at its lower end by an expander while the upper end
remained free to move radially, both elastically and by fretting in
the expanded split end.
At this time, some stems reverted to the slant cut wedge that had been
used on department store bicycle, because it had a longer clamp zone.
The result was that these stems are rotationally insecure and with
forceful riding unscrewed the stem expander bolt.
All this came to a head when MTB bars with their larger width and
often greater offset overloaded the quill stem to the point that it
broke off on occasion besides experiencing the corrosion failure more
readily. The corrosion failure occurs primarily because the stem
pumps from side to side and in wet weather introduces water laced with
sweat into the interface. The pumping motion was not readily evident
because it was partly elastic compliance and not made up entirely of a
loose fit in the steer tube.
Quoted message said:And it's not like threadless is any cheaper, the headsets are more
complicated, the steerer tube has to be longer (and selling one that
has been cut down second hand ought to be a crime), and even the
stems are twice as complex (even compared to quill stems with
4-bolt, easy-change bar attachment side). And lower end bikes need
even more complicated stems with a pivot to have even the slightest
adjustability, which is something people count on getting on those.
As with tubular tires, we will see defenders of the ill conceived
quill stem for many years.
Quoted message said:As far as I'm concerned, threadless should be the domain of weight
weenies.
I suppose if you don't want to recognize mechanical realities, you can
remain in that belief without doubt. You might consider some of the
tradeoffs:
http://www.sheldonbrown.com/brandt/threadless-headset.html
Jobst Brandt
