Low pressure gauge doesn't register. What am I missing?

bme107 · Jul 21, 2013

It doesn't read no matter what presta valve I put it on. Stans, forte, specialized, bontragger. It would appear that there might be something missing in the chuck which would depress the end of the valve down to release air into the gauge. I can put it on and take it off and never hear air movement. The clear rubber sleeve only allows a valve about 3/4's deep and can never bottom out against the back of the chuck body, releasing air.
The gauge does read if I hook it directly to a pump, so the dial isn't defective.

What am I missing?
This is what I've got:

SmooveP · Jul 21, 2013

Mine looks exactly the same, so you're not missing any parts. Does the release valve button move freely and spring back?

bme107 · Jul 21, 2013

Yes, other than on a presta valve it appears to function normally. I put an adapter for inflatable beach toys on a foot pump and wedged the cone into the chuck up against the rubber gasket. Half a stroke and the gauge is reading. Release valve bleeds it off.

As you can see below the gasket stops at the larger threads where the nut turns on. At that point the tip of the valve is within the gasket with nothing to depress it letting the air reach the gauge.

autodoctor911 · Jul 21, 2013

Have you tried different positions of the nut. I have had some pumps not work with the nut all the way out. I had to leavit only unscrewed about 1/2 to 3/4 of the way out, I assume because it was blocking the air when all the way up.

autodoctor911 · Jul 21, 2013

Is it too hard to push it all the way over the larger threads?

It can't get as good of a seal around the threads as against the tapered part between the small and large threads, but that is how some of them are designed to work. they usually use a softer gasket for that though.

SmooveP · Jul 21, 2013

My gasket is pretty soft. Try pushing harder. It may just be a matter of breaking it in.

bme107 · Jul 22, 2013

Without the brass collar on it the gasket presses over snugly and the outer diameter expands. Once you put it inside the collar there is no way to push it down since there is no room for it to expand. I tried it separated from the gauge body so I could see the valve tip and it still comes up short.

I guess I can try running an oversized drill bit down the inside by hand to see if I can shave a bit of the material away.

autodoctor911 · Jul 22, 2013

I would try pushing harder before using a drill. It can't expand inside the collar, but the material should give way, and shear off a little at a time until it fits over easily, then over time, more will wear off, until you need a new one.

If it just won't go, it may be too hard from sitting on a shelf for too long. Maybe try to find some rubber hose the right diameter and thickness, and cut a short piece to replace the gasket.

Why are we using presta valves on 3-4" wide rims anyways?

I don't think an 8mm hole vs a 6mm makes much difference to a 100mm wide rim, like it does on a wimpy little road race rim, where the 8mm hole is taking out almost half the rim width in some cases. Heck, we are drilling 1.5" holes in the rest of the rim.

duggus · Jul 22, 2013

Return it. Get a tiny $.99 presta to shrader adapter online or at any bike shop, and use a low psi normal shrader gauge like you can get for $5 at any big box department store.

bme107 · Jul 22, 2013

I've got the adapter and a nice/big schrader dial gauge with a 10" hose extension on it. Though more pieces to fiddle with I guess this will be my back-up if I can't sort this thing.

bme107 · Jul 31, 2013

Update: I removed the core from an old valve stem and pushed the larger threads as hard as I could into the gauge to hopefully crush the gasket down. Broke some blood vessels in my palm and left an outlined ring of the stem that lasted a couple days. Let the gauge sit like that for a day or two. When I removed the old valve it must have worked some because I was able to get the gauge to slide on far enough for a short enough burst of air to take a reading. It still does not stay set in the deep position because bleeding it off only let out the air trapped in the gauge. Had to jamb the gauge down again to take another reading from the tube.

I assume after a few days sitting w/o a stem lodged inside that the gasket will go back to it's original shape. I'm probably going to try and over-drill it.

Low pressure gauge doesn't register. What am I missing?

bme107

SmooveP

bme107

autodoctor911

autodoctor911

SmooveP

bme107

autodoctor911

duggus

bme107

bme107

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