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-   -   Mystery Flats . Why.? (https://www.bikeforums.net/general-cycling-discussion/823888-mystery-flats-why.html)

cyclezealot 06-08-12 11:04 AM

Mystery Flats . Why.?
 
I prefer to change my flats slowly and systematically . Seeking out where was the puncture and why. I prefer some preventative maintenance to avoid flats on group rides....
. Sometimes small , embedded fragments of glass or whatever are hidden within the tread. Unless you take a close look you might miss it..
After 3 slow partial leaks I took apart the tire to find out why.. All looked well. Nothing embedded in the tire . I put the tube under water. No leaks are to be found anywhere. So, I used it again.. Next day a flat. Afterwards, I again submerged the tire in water. No apparent air bubbles after a prolonged time under water.
I changed it anyway.
I'd call that a mystery flat.

ThermionicScott 06-08-12 11:16 AM

Try pumping up the tube a little more before submerging -- it could be that the tube doesn't leak at a low enough pressure.

CommuterRun 06-08-12 12:42 PM

I was getting mystery flats on a bike at one time after I changed the rim tape. At this time I never had a flat on this bike while I was riding. Only when the bike was parked. I would come back and find I had a flat. It took me several blown tubes to figure out what the problem was. The valve hole in the new rim tape was just a wee little bit smaller than the valve hole in the rim. This was enough to prevent the tube from fully seating against the rim in a small area around the valve, leaving a space in that area in which the wall of the tube had no support. That small space in which the wall of the tube had no support would lead to tube failure at any time while the bike was parked. Once I figured out what the problem was I simply enlarged the valve hole in the rim tape with a razor blade and had no further problem because of that.

johnny99 06-08-12 12:44 PM


Originally Posted by ThermionicScott (Post 14330502)
Try pumping up the tube a little more before submerging -- it could be that the tube doesn't leak at a low enough pressure.

+1

Artkansas 06-08-12 03:12 PM


Originally Posted by cyclezealot (Post 14330442)
I'd call that a mystery flat.

Did you check the valve? The components inside can come loose and need to be tightened.

c23 06-08-12 04:04 PM

A little soap in the water will make tiny bubbles more noticeable. Put valve under water and slightly jiggle parts inside valve. Gently and slightly stretch the tube while under water. And for the last trick...check inside valve cap so that there is no tiny pebble in there or anything.

cyclezealot 06-08-12 06:13 PM

I did put the valve under water , but I did not jiggle it. Sometimes , I notice the valve becomes bent and soon after a valve leak develops. Not so this time. I still have the tube, I'll give it another dunking.

hillyman 06-08-12 06:45 PM

Tube is cursed by demons. I wouldnt trust it. Tubes are cheap.

cyclezealot 06-09-12 03:57 AM

Two flats with no explanation . ^. I just wanted to know why a mystery flat went flat. After the second flat , the old tube was history. It is not worth the hassle. Since it was only partially deflated it must have been a slow leak through the valve stem is my belief. So slow it did not cause bubbles as it was dunked in water. ?

ahsposo 06-09-12 06:25 AM

Make sure your rim tape is completely covering the spoke holes.

Pobble.808 06-09-12 08:17 AM

Sometimes there is a tiny crack in the rubber right at the base of the valve stem and it doesn't show up when you dunk it unless you move the stem around a little.


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