bent presta stem

On Mon, 3 Mar 2008 11:57:01 -0600, Hell And High Water
wrote:

In article ,
says...

A dual-head bicycle pump pushes air through whichever hole has some
back pressure, using a clever little ball arrangement.

This one only has one head, IE one 'hole' where the air comes out. Says
it works with both presta and schrader....

Good call on the LBS. That's actually where I bought it. I'll head
over there and ask them.

Thanks!

-Bob

Dear Bob,

Sorry, my mistake--I thought you meant a dual-head Schrader-presta.

You may have a single head with a reversible internal fitting.

If that's the case . . .

You have to unscrew the collar around the chuck, remove the internal
fittings, flip things around, re-insert them, and screw the collar
back on.

Here's a pictu
http://i32.tinypic.com/2n04mdc.jpg

Left to right:

A) collar
B) soft pressure fitting that clamps valve
C) reversible doohickey, presta one way, Schrader the other
d) pump body

Cheers,

Carl Fogel

In article ,
says...
On Mon, 3 Mar 2008 11:57:01 -0600, Hell And High Water
wrote:

In article ,
says...

A dual-head bicycle pump pushes air through whichever hole has some
back pressure, using a clever little ball arrangement.

This one only has one head, IE one 'hole' where the air comes out. Says
it works with both presta and schrader....

Good call on the LBS. That's actually where I bought it. I'll head
over there and ask them.

Thanks!

-Bob

Dear Bob,

Sorry, my mistake--I thought you meant a dual-head Schrader-presta.

You may have a single head with a reversible internal fitting.

I think it's this one:

http://www.bontrager.com/model/05265/en

I don't think I'm supposed to change anything. It says:

Auto-select head instantly fits both Presta and Schrader valves




-Bob

On Mon, 3 Mar 2008 14:04:39 -0600, Hell And High Water
wrote:

In article ,
says...
On Mon, 3 Mar 2008 11:57:01 -0600, Hell And High Water
wrote:

In article ,
says...

A dual-head bicycle pump pushes air through whichever hole has some
back pressure, using a clever little ball arrangement.

This one only has one head, IE one 'hole' where the air comes out. Says
it works with both presta and schrader....

Good call on the LBS. That's actually where I bought it. I'll head
over there and ask them.

Thanks!

-Bob

Dear Bob,

Sorry, my mistake--I thought you meant a dual-head Schrader-presta.

You may have a single head with a reversible internal fitting.

I think it's this one:

http://www.bontrager.com/model/05265/en

I don't think I'm supposed to change anything. It says:

Auto-select head instantly fits both Presta and Schrader valves

-Bob

Dear Bob,

Sorry to keep misleading you--that is indeed an auto-select, no-fuss,
fits-either chuck design, so it may well be defective.

If your LBS still has the same model, they can take yours and compare
how they work on a tire. If it no longer works, then they might offer
to replace the fitting or even the whole pump. If neither model works
very well, then a new pump is the answer.

Cheers,

Carl Fogel

In article ,
says...
On Mon, 3 Mar 2008 14:04:39 -0600, Hell And High Water
wrote:

In article ,
says...
On Mon, 3 Mar 2008 11:57:01 -0600, Hell And High Water
wrote:

In article ,
says...

A dual-head bicycle pump pushes air through whichever hole has some
back pressure, using a clever little ball arrangement.

This one only has one head, IE one 'hole' where the air comes out. Says
it works with both presta and schrader....

Good call on the LBS. That's actually where I bought it. I'll head
over there and ask them.

Thanks!

-Bob

Dear Bob,

Sorry, my mistake--I thought you meant a dual-head Schrader-presta.

You may have a single head with a reversible internal fitting.

I think it's this one:

http://www.bontrager.com/model/05265/en

I don't think I'm supposed to change anything. It says:

Auto-select head instantly fits both Presta and Schrader valves

-Bob

Dear Bob,

Sorry to keep misleading you--that is indeed an auto-select, no-fuss,
fits-either chuck design, so it may well be defective.

If your LBS still has the same model, they can take yours and compare
how they work on a tire. If it no longer works, then they might offer
to replace the fitting or even the whole pump. If neither model works
very well, then a new pump is the answer.



Thanks so much for your help!

-Bob

On Sun, 2 Mar 2008 09:13:21 -0600, Hell And High Water
may have said:

Seems I'm not smart enough to pump up a tire...


The little stem/rod on my tire valves keeps getting bent. I have a
decent Bontrager pump, but it has a nozzle that fits both presta and
schrader valves.

I can't seem to get it to seat correctly. When I first try to attach it
to the tire all the air rushes out, then I close it down, and it never
seems to be seated correctly. Sometimes no air is getting into the
tire, other times there's a delay, where the pressure goes way up, then
backs down to the correct amount.

Is this the bent stem? The two way pump nozzle or am I just dumb?

A bent Presta will often fail to seal properly in my experience. To
keep from bending the stem in the first place, get a pump that has a
hose rather than one whose head is on the end of the pump's body.
Some people are able to pump a Presta with a hoseless pump and not
bend the stem, but I'm not confident that I'll be among them when I
need to be; I carry a Topeak Road Morph for that reason. (At home, I
can cheat; I have a compressor.)

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

I believe that for pumps that use no hose, instructions on how to use
them, in bold print with an illustration, should be included. This
has been a problem with on-the-road pumps as long as I can recall.
Such pumps require that the user pump from one hand into the opposing
fist holding the pump head. For high pressure, holding the wheel with
grip over the tire is sure to bend (crack) the stem.

Presta valve stems are not designed to take lateral loads although
they will survive low pressure pumping. Do not pump against the stem,
but rather into the other fist that is holding the pump head onto the
valve stem.

Jobst Brandt

thumblock heads from SKS or Parks listed as follows:

http://www.bicycletoolsetc.com/index...mp-Parts&q=&s=

http://www.parktool.com/products/det...7&item=PFP%2D3

14. Silca Chuck for Presta/Schrader Brass/ Nylon
Item #SI-30: . $5.95 plus shipping More Info

Or the Silca chuck

Maybe the answer to the expletive deleted cheapo pump heads, if you
braze or pay for it. Welding or industrial supply probbably have
fittings matching say a Road Morp pump to a thumblock or silca chuck.

Clearly, a cheap pump head is imbecilic design, the thumblock the
answer. Maybe a Silca, no experience here but reviews are good.

On Mon, 3 Mar 2008 19:27:53 -0800 (PST), datakoll
may have said:

thumblock heads from SKS or Parks listed as follows:

http://www.bicycletoolsetc.com/index...mp-Parts&q=&s=

http://www.parktool.com/products/det...7&item=PFP%2D3

14. Silca Chuck for Presta/Schrader Brass/ Nylon
Item #SI-30: . $5.95 plus shipping More Info

Or the Silca chuck

Maybe the answer to the expletive deleted cheapo pump heads, if you
braze or pay for it. Welding or industrial supply probbably have
fittings matching say a Road Morp pump to a thumblock or silca chuck.

Clearly, a cheap pump head is imbecilic design, the thumblock the
answer. Maybe a Silca, no experience here but reviews are good.

A thumblock lever is not a guarantee of a good head. I've got a
Serfas pump that came with their version of thumblock lever head, and
to be blunt, it sucked. Or, rather, it blew...air out all the time.
I whacked the hose off and substituted a Zefal head, which solved the
chuck problem...at which point it became possible to get the pressure
up high enough that the pump's sealing failed at three other points,
including the tube/lower body joint and the hose elbow on the pump
base.

I scavenged the Zefal head back off, swapped it onto a cheapie
all-metal-body floor pump that I'd had around for 30 years (it was
Schrader-only, with the old-style "empty all of the air from a road
bike tube before you can get the hose end completely unscrewed"
connector) and stuck a T-fitting in the hose to connect a cheap
pressure guage. That worked.

Needless to say, I haven't bought any more Serfas pumps, though I have
nothing specific against any of their other products.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

WHR-

problem is: where are the fittings found or how did you fit the pieces
together?
I found nothung small enough at Home Depot, haven't searched a more
complete stock of fittings.
The ususal run of gas hoses are too large for road pumps. I guess the
Parks is off gas line diameter, Parks sez larger diameter.
local noise is the SKS is no longer manufactured

I usually use Goop here but an untried glue is:
3M Scotch-Weld 3532 B/A Urethane Adhesive
$15/ 2 0z. tube kit (6 per case)
Available from
Hillas Packaging

Cateye could try their hand at designing a pump.