Originally Posted by
CliffordK
One tube, you might think of a bad valve. But not lots of them.
My guess is you're just not finding the leak. Put a little more air in the tubes when you have them sitting overnight, or when you are looking for leaks in a bucket of water (2x or 3x their "normal" size)
Those fine radial tire wires can seem almost invisible in the tire, but are like tiny needles.
I'm going with this. Often those very fine wires can be embedded in your tire and pierce the tube when it's inflated. I've found those wires by turning my tires inside out and very carefully examining them.