Tires rubbing

73 swinger. When I bought it one of the front and rear tires would rub on the fender when turning or breaking hard at speed. Every thing looks right. I know shocks were changed and some jegs cheap rims put on. I was thinking maybe the offset on the rims is off because the tires are not overly wide. Thoughts? Is there a way to calculate wheel offset and know what it should be? Would a tire place be able to check it? Thanks