So i took a big gamble today and bought some used winter tires off of craigslist.
They were Hankook Ice Bear W300 Error - Discount Tire
The guy had 4 barely used 245/45/18's. All of them are at 10/32 tread deapth and i paid $300 dollars. I can confirm at least for this tire and size that a 245/45/18 tire will fit on the rear 7" wide wheel. Not alot of clearance between the inner side wall and strut but probally a 1/4 inch. So far great tires.