[Yosemite Sam]

I suggest that when you try to inflate the tire, some (perhaps quit a bit) of the sand would want to escape from between the tire and the wheel.

Once the bead does seal, I believe some of the sand would be trapped between the wheel and the bead of the tire, this could potentially cause the bead to leak and over time, the trapped sand could eat away the edge of the tire and the wheel as well, only causing the leaks to become worse.

I do think someone should try this and report back to us, maybe a couple of times a year, in ten years or so we will have a definite answer.