got what I needed from the link, thanks. 24x4 isn't much to get excited about. there is no sense of scale in the photos I had, so I was excited that it might be more like 26x5. 24x4 makes sense for an offroad wheelchair from a gearing perspective though, I guess.
the roleez tires also look cool for a project... maybe a single wheel sand bike trailer. They don't seem to be for snow use though, with minimum service temperatures above 0F. They also don't seem appropriate for use a drive wheels, given the means of hooking the tire to the hub. Still cool that they exist, and I suppose running them below their rated temperature (looks like they may be welded pvc sheet, like pond liner material) might just result in more rolling resistance and a shorter life, not catastrophe...