Tire pressure anomaly

DeanR

DeanR

Joined
Jul 28, 2007
Messages
3,153
Location
finger lakes ny
Bike
1999 ST1100
STOC #
7959
A couple weeks ago I went to back the bike out of the garage for a grocery run. Always an easy go. Not this time.
Turns out the front tire had virtually no air. This has never happened. Tires are always more or less good to go. Per feel, per gauge and per TPMS. Even if it has been parked for a while, which rarely happens.
Aired it up and has been fine since.
Can’t come up with any idea how this one time thing happened. I need help solving this mystery!
 
That core has an o-ring as well so if it's old, it may be the issue.
 
ToddC said:
Anyone else have access to the bike...?
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:) nope, (except for the public in parking lots)

flyfisher said:
Stuck valve stem core from when you last aired up or checked with gauge?
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Possible, though never had that happen.

Mellow said:
That core has an o-ring as well so if it's old, it may be the issue.
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Possible also. Kurvey Girl 83 degree stems. Do people replace cores periodically? I think I have a couple spares.
 
DeanR said:
:) nope, (except for the public in parking lots)


Possible, though never had that happen.


Possible also. Kurvey Girl 83 degree stems. Do people replace cores periodically? I think I have a couple spares.
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easiest is the spray soapy water and air up the tire and see what bubbles up.
 
DeanR said:
A couple weeks ago I went to back the bike out of the garage for a grocery run. Always an easy go. Not this time.
Turns out the front tire had virtually no air. This has never happened. Tires are always more or less good to go. Per feel, per gauge and per TPMS. Even if it has been parked for a while, which rarely happens.
Aired it up and has been fine since.
Can’t come up with any idea how this one time thing happened. I need help solving this mystery!
Click to expand...

How long did it sit without you riding it before you noticed the flat?
 
DeanR said:
Do people replace cores periodically? I think I have a couple spares.
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Periodically? No...well, I doubt it. The reason for my waffling is that while I've never heard of anyone making a practice (anyone = my mechanically inclined friends and in my readings) of doing so, I am sure we have at least one member somewhere who does (I'd call that an anomaly). Rubber valve stems are almost always changed with a tire (cars); with angled metal stems, T stems, and some of the esoteric OEM ones found on Beemers regular core changing might become standard...at least regular will come to mean 'with the tire'. I do know that on our Highlander, renewing some rubber parts on the valve stem when installing new tires is recommended.
 
I had an intermittent leak on a car tire once that was finally determined to be caused by a tiny bit of wire penetrating the tread. Turns out it only leaked with the weight of the car on it and when parked with the puncture in a particular orientation, under the tire. Must have been the slight deformation of the tire when parked that way that caused it to leak. No leak, with the tire off the car and submerged in water, could be found. Finally a sharp eyed tech at the tire shop noticed the tiny wire on the inside of the tire, removed it and patched the tire. No more problems after that.
 
I have seen this strange pressure loss happen twice - once on my Africa Twin rear tire and another time on my wife's Volvo. Both times it happened for the same reason.
Has the temperature where the bike is kept gotten fairly cold while the bike was sitting?

The problem I had was caused from an issue with the bead not sealing - on the bike this happened due to some small rubber whiskers that were molded into the bead seating area of the tire and on the Volvo it was due to not having the bead seat area on the rim clean after having new tires put on.

The tires held air fine through the warmer months as the rubber was flexible and was able to seal but in cold weather when sitting the bead area developed a small leak and the tires lost air. This only happened when the tires got cold - the tires held air fine after warming up and being driven or ridden. It took me a while to figure out what was happening When I checked the cold tires with soapy water I finally detected a very slight bead leak only when the tires were cold that disappeared when the tires warmed up.

I clipped off the small rubber whiskers and the leaks stopped on the bike and I had the leaking tire removed from the car and had the rim cleaned well and both tires stopped losing air when cold.
 
Mellow said:
easiest is the spray soapy water and air up the tire and see what bubbles up.
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No soap bubbles after air installation. Didn't check the whole tire but gave it a good lookover.

MidLife said:
How long did it sit without you riding it before you noticed the flat?
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Just a couple days.

bdalameda said:
Has the temperature where the bike is kept gotten fairly cold while the bike was sitting?
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Not when this happened. Does get ridden throughout the winter though when the roads aren't white..
 
DeanR said:
No soap bubbles after air installation. Didn't check the whole tire but gave it a good lookover.
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It would be a good idea to do the whole rim on both sides. If there is some corrosion (doubtful from what you have said) the bead might not be seating and you might have a slow leak. Last I heard, a good lookover is no good for gas leaks, but I admit I don't know if it can detect small air leaks.
 
pull the wheel off, lay it flat, spray soap and water on the bead area and come back in 5 min. If it's a slow bead leak you will see foam forming at the leak. Try it at normal pressure and 10-15 lbs. less.
 
My rear tire was completely flat yesterday. Ridden 2 weeks ago and no prior air loss. Didn’t find any foreign objects in the tire. Nothing visible. Used soap and water and found a rock poke bubbling like crazy. Dismounted it and patched from the inside. Hope you get it sorted. Nothing spoils a ride like a low or flat tire.
 
At the risk of poking a hornet's nest......do you use the glass type balance beads?
I used those once. The glass turned to a fine powder and would cause the valve core to stick open sometimes after I had checked the pressures.
 
drrod said:
At the risk of poking a hornet's nest......do you use the glass type balance beads?
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No tire 'additives'. It's been ok since the problem appeared and aired up, but I do have to hunt for my extra valve cores.
Also oughta do a thorough soapy water test, not just the valve.
 
Is it possible that you ran over a nail, close to home, on your last ride? Parked the bike, and the rest is history. It’s happened to me twice in 14 years.

John
 
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