I have had trouble mounting Vittoria wire bead tires (700x32) on my Sun CR18 rims. I went ahead and bought folding Panaracer 700x28 and steel levers. When I got the steel levers I rounded them off (chamfered) a bit on the wide end so that they would not pinch the tubes. With a little practice I got pretty good at mounting, taking off the wheels off this rim. I went ahead and mounted the Vittoria wire bead tires on a different set of rims, Alex CR22, they went on pretty easily. My guess is that the combination you are trying is the culprit. The rims probably have a high sidewall and the wire bead is having a hard time making it over...