Solid tires are not popular, because they are heavy and nobody except you,
chesterv, has this problem. I think, you should not look for the solid tires, but for the reason of your problem. If you are saying the you try to change tubes and tires, probably problem is somewhere else.
What pressure do you usually pump up to? Maybe it is something extreme? Do you have the same behavior for both wheels? Might be something is wrong with the rims and they are making small puncture in your tubes. First i think you need to make sure that there is no puncture: take the tube out, and pump it up to really big size (but avoid explosion
) and dip it in a bath, try to see attentively for bubbles, if you see it, let me know, i will give further recommendation
. If no, the only one explanation is left is pump and valves (nipples). Maybe you pump damages nipples and they do not keep air any more. Might be, there is dust in your pump that comes into the tube and prevent nipples to work well. What kind of nipples do you have? If you have presta valve, do you do everything exactly like it this
video?