5 Series Tires Rubbing on back of 320i

Hello All! I got a 320i (1993) that needed new tires. A friend of mine was getting rid of his OEM 525 Tires with Rims. I tried one on the front and it had no issues whatsoever, although the turning radius was a little diminished. Anyways, I put all 4 tires on after purchasing, and I realized that the rear tires rub somewhere (I can hear it sometimes when driving) I can't afford new tires, and this is my family car, which means there are at least 4 people most of the time. My original rims were 15 inches, and these are 16s, so I didn't think there would be any issues. it rubs as it is, let alone with someone sitting in the rear seat. I don't know what to do, is there a way to lift the vehicle up another inch to offset the 1 inch difference in rim size, (like a spring lift block kit) or new shocks that might lift it up enough so it doesn't rub? I'm a little disappointed right now.

I am new to BMW's but not cars. What year and model is the 5 series your new wheels n tires came from? This may make a difference (Width, wheel offset).

What is the size of the NEW tires?

More information in a forum post is usually a good thing :)

you went from a 15" rim to a 16" rim... there's a thing called "plus sizing" to keep the overall diameter the same for clearance and speedometer issues

google it if you don't believe me

/\ = True enough. You should post the tire size from your old 15's also.