sorry dude, but 235 is way too big for a 7" rim. it can be done, but really shouldnt be. according to the tyre manufacturers, 235s should go on an 8.5" rim, and they will then sit dead flush with the rim. 235 on a 9 is just a tiny bit stretched.
drift limo: are your rims upside-down rims? if they are, beads get ripped tryin to strip tyres off when theyre not mounted on the machine upside down.
just a thought