Are you trolling?

Air escaping tube = tube not holding air.

Whether it is a visible gash (impossible to inflate) or a pinhole (slow leak), air is leaking out.

And you have simply failed to locate it.

Take out the tube. Inflate it. Submerge in water. Note location of air bubbles.

EDIT: When submerging in water, there must be enough air pressure to force the air out of the pinhole. This may require squeezing the tube while submerged.

This whole thread: LOL.
Just take the bike to the bike shop.
Make sure you bring the receipt.
Ask for a return.
When they ask why, tell them they sold you a defective bike.
Take the refund and buy a pair of Reeboks, but not the pumps, those don't hold air either.

...and if you aren't trolling, I apologize.

He is Not Trolling.

Twice I have had Schrader tubes go completely Flat.

Water tested found Nothing. Removed valve cores, reinstalled.

Still use the tubes today.

Last year I had a similar situation. Kept losing air in a tire/tube overnight, but not all the air. Could not find a leak when submerging. But eventually did find that the tire was falling apart in one spot, that somehow kept pressing the tube in one area and leaked out enough air.

I didn't realize this until I submerged the tube and start squeezing the the tube in various spots to force air out of it. Then I was able to find the hole. Very tiny hole at that.

This is how to find pinholes.

No. Are you? Since you obviously couldn't be bothered to take a gander at the earlier posts, it would be more accurate to say that you're the one who came here with the intent to troll. Me? I'm just having a bad day.

We used to call those "high pressure leaks". With the tube out of the tire and pumped to a low pressure, the puncture hole was so small it would not leak. When installed back in the tire the higher pressure would allow the puncture hole to open and leak. After a careful check of the tire, we usually just threw in a new tube and was done with it.

I have over the years been successful in finding some of these leaks by blowing up the tube as much as possible (without causing it to blow out of course), then submerging the entire tube in water in a large container. Some bubbles will form on the tube when you submerge it so take a minute and wipe all of those off. I usually place some weights on the tube to hold it down. Then watch very carefully for tiny bubbles...you might only see one bubble every 20 or 30 seconds. It takes a bit of time and careful observation to track down this type of leak.

Also look very closely at seams in the rubber and where the valve is attached. I would say that fully half of the ones I have seen were actual manufacturing defects. Also look real closely at any existing patches.

Hold on a sec.. is the tube in the Kenda, one of the tubes that previously went flat in the other tire? Or a fresh tube that was never in the problematic tire?

In fact, I did read the earlier posts. Except for the guy going on about valves, we're all saying the same things.

The explanation is that there is a pinhole. Lower pressures don't generate enough force to open it up, but higher pressures might.

The reason the tube in the Kenda is holding air is because whatever made the holes is in the original tire.

Also, if the tire is rated to 110psi, that's the max. Don't pump it to 115.

Yes, it's one of three tubes that lost all their air in the Primo. It has been sitting inside​ the Kenda for a day now, at the same 50psi I pumped it up to yesterday afternoon. This is the one that's​ already been patched twice.

I thought it was at 70 psi?

It was before I dropped it down to 50 and went out for a ride (the Kranium is rated at 40-65psi.)

Toss the tube, maybe try 10 Wheel's suggestion with the valve stem first. Life is too short to spend much time on a bad tube.

Well, it's not a bad tube when it's in the Kenda! But they're all bad tubes when they're in the Primo!

I also think it's a radial tire wire. They are very fine, nearly impossible to see, and very sharp. Because they are so fine and sharp, they poke a very small hole in the tube when inflated to full pressure and the tube material is stretched. The tube loses pressure relatively slowly, like overnight, but doesn't go totally flat because at a lower pressure (say 20-25 psi), the tube material compresses sufficiently to seal. It's maddening.

So, as suggested above, take the tube out, flip it back, and run a cotton ball or microfiber cloth along it. Once you've found it, you'll need needlenose pliers and a very bright light. Like direct sun. Good luck.

Toss the Kenda then. At least put a different tire on, and some time when you're bored turn it inside out and feel around, peer through a magnifying glass, scrub it or whatever might work.

You mean toss the Primo! They're A-Okay inside the Kenda!

Why don't you pump the tire up on the rim and put it in you bath tube and see where it leaking that way. It may give you a starting spot . Then again maybe not . Leave the valve cap off and start there.

STOP destroying good tubes will ya, just listen to what everyone is telling you, find the object inside your tire or rim causing the flats and remove it

ran into the same thing- and fixed it
 

I had the same problem with car tires (2). It turned out my hand pump was damaging - a very small bend- the valve stem. Tires that had no leaks would leak down to about 25 psi. And hold there with no problem. New valves solved the problem until I "topped off" the pressure a couple months later and the problem repeated itself. SOLUTION: DIFFERENT HAND PUMP. The presta side of my pump still works fine, only the schraeder gave the problem.