I couldn't do it man; I've got my white wall Columbia Superb tires at like 40-45 psi & it rides Great, tires don't smoosh with me at 160-180 lbs & with a girls sprocket it's easy peddalin' but I know those wheels aren't even 2" wide so I am Verrry Leary of too much air in a rubber in an even smaller metal space.
I don't know if any of you guys ever seen tubes outside of the rims but now days they Never seem to inflate evenly. I worry about pinch flats .... Hell my 26x3" Duro tires don't run 60 psi
Quick ? Have you tried inflating other tires that much? I am curious