Could you explain that a little more dude? I have 10's on the back and don't have any ballooning or anything on my tires. Maybe I'm not understanding what you mean.
If you look at the cross section of a tire, you'll notice that its flat on the contact patch, and then it curves (the radius) to meet the sidewall. That radius can make or break the fitment of the wheel on the car.
Some tires, have a shorter radius compared to other tires. S03s are a more square radius. Blizzacks are a VERY sqaure radius. My p7000s that were on my 16s, were a more rounded radius. The more round the radius, the more baloonish the tire looks.
My wheel guy wouldn't order me wheels based solely on wheel specs. He had to know what tires along with the wheels and suspension setup.
I'm sure I'm missing more of the equasion as he didn't go into great depth. This is pretty much what I remember.
Trent.. i'll be calling you shortly...