The Geax tires that came on my 29er with Weinmann rims rolled right off. Or would if I'd let them. But with 2-2.5 Bar they've stayed on for all the riding I can manage.
OTOH, I don't think I have a single bike that can be wheeled any kind of distance with uninflated tires w/o things getting messed up. The tires do tend to "walk" on the rim, dragging the tubes with them and tilting the stems.