Luns Tee wrote:
> In article <[email protected]>,
> damyth <[email protected]> wrote:
> >The "modern" chuck is prone to blow offs. When it doesn't blow off it
> >leaks air, to which to have to resort to holding the chuck while
> >simultaneously pumping. (Yes, new rubber grommets, and made sure that
> >the upper cap is securely compressing the grommet against the valve,
> >once it has been mounted for pumping.)
>
> I don't know what you're doing wrong, but I've never had a
> problem with the current 30.0 chuck, or the 24.0 chuck it's based on.
>
> >The older "unsurpassed" reversible design was beautiful. I tried to
> >find a pic of it on the net but can't find one, since it probably
> >preceded the arrival of the internet outside of educational
> >institutions. Imagine the top half of the "24.0" chuck. The old chuck
> >essentially had a design which the bottom was a mirror image to the
> >top. It had two rubber grommets, one on top and one on the bottom.
> >The chuck barrel had an internal shoulder to support the grommet that
> >almost spanned 80% of the cross sectional barrel area, providing firm
> >support to the rubber grommets.
>
> I think this chuck was designated as the 27.0. It uses the same
> chuck washers as the silca impero (washer 323.1) if I'm not mistaken.
> I have one of these chucks too and haven't had any problems with it,
> but haven't found it to be any better (or worse) than the 24.0/30.0.
>
> >The brass part that actually connected
> >to the hose actually allowed the chuck to rotate independently of the
> >hose, to prevent any "kinks" to the hose while pumping.
>
> Rotating is only relevant for schrader where you screw the
> chuck onto the valve. For presta valves, I don't see why you don't
> just untwist the hose _before_ you push it on.
>
> >I sincerely believe the older chuck design was why everyone bought
> >Silca pumps during the mid eighties. Now you'd hard pressed to find a
> >Silca floor pump in a LBS.
>
> The presta chuck that people generally raved about then was
> the 24.0, while all the complaints I recall hearing were about the
> about the reversible chuck that you're praising. I don't understand
> the fuss though - I've never had a problem with either design, except
> that I find both a little annoying to use on schrader valves, needing
> to be screwed on instead of pressed/clamped.
>
> -Luns
Well, that's exactly the point, isn't it? Blame the "clueless"
operator for using the thing incorrectly when the chuck itself doesn't
work worth a damn. FWIW, I tried at least 2 new grommets and different
orientations, and it still worked like ****. I wouldn't wish this
chuck on my worst enemy.
As I stated earlier, instead of putting up with the frustration of the
Silca 24.0 chuck I went ahead and bought a cheap replacement PLASTIC
"auto-sensing" chuck/hose combo from a well known mail-order house. In
this household there are 6 bikes for 3 people (all daily bike
commuters), and this chuck has served us well for the last year or so.
With no fuss and muss, compared to the Silca 24.0 chuck.
While the plastic chuck is not with it's disadvantages, it functions
light years ahead of the Silca 24.0 chuck. I'm almost certain the
rubber grommets inside that chuck won't be available separately as
parts. The auto-sensing function also depends on back-pressure, which
is a bit problematic when attempting to pump a new tube. But there is
an easy workaround for this which I've posted on another thread.
BTW, I think you've accurately described the "27.0" chuck which I
praised earlier. There were a few revisions of the 27.0 chuck, and not
all of those worked well. For example, not all varieties of 27.0
allowed the chuck to rotate independently of the hose, and this posed a
problem for the Schrader attachment, as you commented. There was only
one particular version that worked well for me, and it had two brass
"washers" inside, to give additional support to the rubber grommets,
iirc. If you know anyone who has one of these 27.0 chucks for sale,
I'd be grateful for the reference.