I have lately been having considerable trouble mounting and dismounting no-name Taiwanese tires on 27" rims. I broke my first ever tire lever yesterday, trying to mount a very old Continental 28 x 1 1/4 onto an Araya 700c rim. I had earlier taken it off without any trouble(I bought them as a unit).
I just now went and checked to see what it was, and found for the first time that it's a 28" tire. Are they known to fit 700c rims? That would significantly broaden my tire options, as 28s are quite common here.