help with tire size

I just purchased a set of vb3 rims specs are 19x9.5 and 19x10. for the tires i purchased 235 35 19 and 275 30 19. i'm concerned that in a couple months when I drop the car the 275 will rub. I don't want to have a straight side wall i would like to stretch it a bit. Would 275 be fine or should I go with a 255 for the back? thanks in advance