Synaptic Adhesion

"App" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

An old room-mate of mine from my college years used to refer to senior
moments experienced by a 22-year-old as episodes of "synaptic
adhesion".

My latest episode involves my new Salsa threadless stem, accompanying
which was a shim to accomodate a 1" threadless steerer. This shim,
unlike the one I received with a Ritchey stem, does not have an upper
flange to rest against the top of the steerer clamp of the stem.
Additionally, the shim is approximately 1 mm shorter than the clamp.

How does one mount a stem with a shim like this? With a flange, I
insert the shim in the stem, the stem is placed on the steerer, the top
cap inserted and tightened till just snug, then I align the stem, set
the preload with the top cap, check the alignment, and tighten the stem
clamp.

Without a flange and being too short (the stem, that is), I just don't
see how the whole installation goes. Can't tighten the stem clamp
before adjusting the preload but the top cap can't push down on the
shim because it sits shy of the top of the clamp preventing the
"transmission" of the tension by tightening the top cap....

Hope that wasn't too g. daniels -

TIA

App

Sounds like all the threadless stems and shims I've seen - never saw the
flanged type you described. Anyway, the top cap is pressing down on the top
of the stem as you tighten the screw. It doesn't need to be pressing on the
shim to set the headset bearing preload. Just be sure the underside of the
cap can't hit the top of the steering tube or you won't be able to adjust
the headset properly.

Cal

Cal said:

Sounds like all the threadless stems and shims I've seen - never saw the
flanged type you described. Anyway, the top cap is pressing down on the top
of the stem as you tighten the screw. It doesn't need to be pressing on the
shim to set the headset bearing preload. Just be sure the underside of the
cap can't hit the top of the steering tube or you won't be able to adjust
the headset properly.

Cal

Ok, yah, but the spacers between the headset and the bottom of the stem
are too narrow (outside - inside dim) to bear against the bottom of the
stem properly - there is a slight bevel that slips into the 1 1/8 stem
and probably would have a damaging,wedging effect on the clamp.

It appears just that I need thicker shims (say, carbon rather than the
aluminum ones I have now) so that the clamp will bear on the shim.

?

Thanks,

App

App said:

Cal said:

Sounds like all the threadless stems and shims I've seen - never saw the
flanged type you described. Anyway, the top cap is pressing down on the top
of the stem as you tighten the screw. It doesn't need to be pressing on the
shim to set the headset bearing preload. Just be sure the underside of the
cap can't hit the top of the steering tube or you won't be able to adjust
the headset properly.

Cal

Ok, yah, but the spacers between the headset and the bottom of the stem
are too narrow (outside - inside dim) to bear against the bottom of the
stem properly - there is a slight bevel that slips into the 1 1/8 stem
and probably would have a damaging,wedging effect on the clamp.

It appears just that I need thicker shims (say, carbon rather than the
aluminum ones I have now) so that the clamp will bear on the shim.

One solution, as you mention, is spacers with larger OD. Another
solution is a longer shim (OD and ID the same, axial length greater). If
neither of these is available, you might try to stack two shims to get
the length you need.

--
Dave
dvt at psu dot edu

App said:

How does one mount a stem with a shim like this?

The normal way, unless the top cap you've got is unusually small. If
so, get a 1 1/8" top cap and use that. The top cap needs to bear on
the stem, not the shim, and the spacers below will (likewise) bear
against the stem unless they're significantly thinner than any I've
used.
--
Typoes are a feature, not a bug.
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App said:

Cal wrote:

It appears just that I need thicker shims (say, carbon rather than the
aluminum ones I have now) so that the clamp will bear on the shim.

The aluminum 1" spacers I keep around have an OD that's a bit more
than 1 1/8", so there's not specific need to go with carbon. Are
yours beveled at both ends? If there's an end that's squared off,
turn the spacer over...
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.