Pneumatic Pressure Gage Presta?

Tom Nakashima said:

We have access to an air line that we could tie into. I was wondering if
anyone knows of a pneumatic pressure gage with indicator for the presta
valves? Similar to ones found in gas stations, but for presta valve use.
Not sure if one even exist. If not I will use the presta adapter.

See: http://harriscyclery.net/site/page.cfm?PageID=49&SKU=PU9997

Sheldon "At Your Service" Brown
+-----------------------------------------------------+
| We can complain because rose bushes have thorns, |
| or rejoice because thorn bushes have roses. |
| --Abraham Lincoln |
+-----------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Tom Nakashima said:

We have access to an air line that we could tie into. I was
wondering if anyone knows of a pneumatic pressure gage with
indicator for the Presta valves? Similar to ones found in gas
stations, but for Presta valve use. Not sure if one even exist. If
not I will use the Presta adapter.

Since most Presta valve chucks have no valve depressor (opener) and
Presta valves are inherently sticky due to their tapered valve.
Measuring inflation pressure doesn't work well with a reservoir
(continuous) pressure supply, the valve being either open or closed.
With a piston hand pump, the valve opens abruptly when line pressure
exceeds stiction of the valve and allows all air from the pump stroke
to enter the tube up to the level of equilibrium. So the reading
after each pump stroke is correct.

You'll have to balance your options. My floor pump performs that task
ideally although a reservoir supply that is largely at a higher
pressure than desired (as at gas stations) will not do that. When you
release the trigger, you may have no idea what pressure is in the tire
and then again you may, depending on the length of hose between the
control trigger and Presta Valve.

Jobst Brandt
[email hidden]

Tom Nakashima said:

Quoted message said:

We have access to an air line that we could tie into. I was
wondering if anyone knows of a pneumatic pressure gage with
indicator for the Presta valves? Similar to ones found in gas
stations, but for Presta valve use. Not sure if one even exist. If
not I will use the Presta adapter.

I already gave a link to one of those.

Jobst replied:

Quoted message said:

Since most Presta valve chucks have no valve depressor (opener) and
Presta valves are inherently sticky due to their tapered valve.
Measuring inflation pressure doesn't work well with a reservoir
(continuous) pressure supply, the valve being either open or closed.
With a piston hand pump, the valve opens abruptly when line pressure
exceeds stiction of the valve and allows all air from the pump stroke
to enter the tube up to the level of equilibrium. So the reading
after each pump stroke is correct.

Sorry, Jobst, you're a bit out of date on this. Modern floor pumps have
high tech air chucks that do hold the Presta pin down. These newer
units also automatically work for both types of valve. I use a Topeak
pump of this description, works fine (though the ergonomics of the lock
lever could be improved. Even got a digital pressure readout.

The Problem Solvers air chuck/gauge also appears to have one of the
newfangled automatic connections.

Sheldon "PSI" Brown
+------------------------------------+
| A good plan today is better than |
| a perfect plan tomorrow. |
| --David Mamet |
| (Wag the Dog, Bulworth) |
+------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

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

Quoted message said:

Tom Nakashima said:

We have access to an air line that we could tie into. I was wondering

if

Quoted message said:

Quoted message said:

anyone knows of a pneumatic pressure gage with indicator for the presta
valves? Similar to ones found in gas stations, but for presta valve

use.

Quoted message said:

Quoted message said:

Not sure if one even exist. If not I will use the presta adapter.

See: http://harriscyclery.net/site/page.cfm?PageID=49&SKU=PU9997

Sheldon "At Your Service" Brown
+-----------------------------------------------------+
| We can complain because rose bushes have thorns, |
| or rejoice because thorn bushes have roses. |
| --Abraham Lincoln |
+-----------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

That's it Sheldon.
In fact the air line on our mating end (quick disconnect) will match the
male fitting on the Air-Bob tire inflator you show. We have quite a few
riders here, now I need to take up a collection.
thanks,
-tom

Tom Nakashima said:

We have access to an air line that we could tie into. I was wondering if
anyone knows of a pneumatic pressure gage with indicator for the presta
valves? Similar to ones found in gas stations, but for presta valve use.
Not sure if one even exist. If not I will use the presta adapter.
-tom

Be careful not to blow the tyre off the rim if you use an airline.
People do it every year when they get distracted and put 250psi into
their mountain bike tyres. Makes you jump!