I've purchased 3 of these inner tubers and they all go flat after a few hours outside. What gives? has anyone experienced this before? They have removable cores, could that be the reason?

Robot Check

I've examined the inner tube and found no punctures. I pump air in and can't feel any air coming out. I pumped it up to 120 psi and it's holding fine. But i bet when I go back outside the tire will be flat in a few hours.

I've installed all 3 and the same thing happened for all tubes. I've examined the rim too and found nothing unusual.

Maybe hold it under water and see where it bubbles?

I'm at work so getting a tub and water is difficult. Not impossible...just difficult. The bosses are in a meeting right now so maybe I should go hit up the sanitation closet.

wait soap and water. could work.

That seems a weird approach to problem solving: focus on irrelevancies over and above the solution. Good luck.

No I took your idea. I found a giant container and dunked the inner tube. Found a small pin hole. I then examined the tire itself and I had to go over it with a fine tooth comb. There was a tiny sharp thing sticking out of it. It was like removing a splinter. I had to poke at it with a thumb tack. hopefully that was it. 3 inner tubes. Man i'm dense.

Next time try running a cotton ball around the inside of the tire, it will snag any objects and cover the area better than fingers (plus no glass cuts). You might also turn the tire inside out to put the inside under tension and help open up any tiny holes with sharp objects sticking out. If you consistently mount the tire in the same position relative to the valve it will be easier to locate the object which is making the holes since you will know its location more closely.

That is a great idea. Wish I had known that earlier.