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Discussion Starter · #1 ·
So, I went riding Saturday, noticed before I left the rear looked and felt low, about 7 lbs down. Hmm, not good. inspected carefully, nothing,
Aired up, got ready, took an hour, and the tire checked out ok.
High speed run to off road area, down about 4 lbs. Hmm again.
3 hours off road, average speeds around 20 - 30 mph. tire at pressure, no problem.
High speed run home, felt funny halfway, down about 9 lbs. Ok, this is weird.
Aired up, got home, down about 5 lbs. Aired up at home, next morn, pressure ok. Weird again.
At work, (high speed run to work) down again. Now I'm perplexed.
Got home, removed wheel, tire and tube, inspected inside of tire, nothing. Aired up tube, no leaks heard. overinflated tube, put in tub of water, rotating to find leak. NOTHING!!!!
I inspected and tested everything, including valve, nothing.
I spent 45 minutes looking for a slow leak, absolutely nothing. I have had MANY flats in my career in riding, this ain't my first rodeo, and have never encountered this.
This morn the tube was just as full as last night, as though there is no leak.
Is it possible that the valve stem spring is weak, and allowing centrifugal force to depress it and cause this issue?? because I cannot explain this one.
New tube today, but **** if I am not frustrated at what SHOULD be a simple issue.
Just weird.
 

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you certainly covered all the possibilities. Looking at your description it does seem that you're only losing pressure when running "high speed". Maybe the force is causing the schrader valve to leak? Maybe replace that inside the stem and see if it helps. Cheap and Easy,. based on your others tests, TBH i dont see it helping....
Maybe a new tube all together?
 

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I would go ahead and replace the core just to rule it out. Whatever the nearest dealership is to you should just give you one if you don't have a spare. I believe wholesale on those is about $8 for 100.

Sent from my SM-G975U1 using Tapatalk
 

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Yea I’d say bad value stem, replace the core and get some decent caps that seal, not the plastic dust covers...
 

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I've had two friends over the years that had valve stem leaks that only showed at speed. In both cases it was the rubber stem.
 

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Tires and tubes get hot when you're riding, and hot air expands. So a tiny hole in the tube or stem that may hold air at the cold PSI can leak when it gets hotter and the pressure goes up. You may have a damaged core - but I doubt it's the spring. I'd just replace the tube and be done with it.
 

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I love these. But need to split with 4 people since they come in packs of 4 and we need different front and rear pressure. But not really expensive so I'll have 3 spares of each...
 

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If you suspect the valve try these, heck try these anyway. Cheap, easy to way to see if your tires are up to pressure. Make sure they are on tight. You get enough to give a friend a set.



https://www.amazon.com/gp/product/B01HRIKB74/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
I have never purchased any of these because I was told many years ago that in the event you break the plastic viewing cap that the tire will loose air rapidly. I am not sure if it is actually true, but if it was is it still the case? Or are there now safeguards in place?

Sent from my SM-G975U1 using Tapatalk
 

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I have never purchased any of these because I was told many years ago that in the event you break the plastic viewing cap that the tire will loose air rapidly. I am not sure if it is actually true, but if it was is it still the case? Or are there now safeguards in place?

Sent from my SM-G975U1 using Tapatalk
I personally do NOT like these “caps” simply because you are relying on the cap itself to hold the air in. I prefer having two seals on the stem; one the valve core and two a sealing cap (Incase the core leaks).

Side note!
When using metal caps LUBE THEM... I use dielectric grease to help stop any galvanic corrosion, usually if you check your air pressure often this is not a problem. But either way it doesn’t hurt...
 
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I run a Zumo 595 and I went with the Garmin cap transmitters for a TPMS given that I did the Outex tubeless conversion. Could not be happier with the result other than it takes movement to wake them up. On the Garmin I use the Left Front/Back of a 4-wheel setup for the ATAS and the Right for the Goldwing, so I get double duty. Just gives me a bit of comfort knowing that I have the TPMS on board.
 
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