I have a pair of the folding Ricorsos. They are too loose on an Alex RP15F rim; it’s usually a pretty bad experience getting them on there. More than half of the time they blow off. Now I usually put about 80psi in them initially, ride a block or two and then get them up to full pressure. This seems to work. On my Alex DA28 they fit perfect. Not a pain to get on but they have never blown off.
Its definitely the rim size that makes a difference in my case.