The standard turning radius is 36'. The cars with 18" wheels and the 235/40 18 tires have a wider 40' turning radius. I know because it ticks me off everytime I try to make a u-turn in front of my house. Small price to pay.This is supposedly to keep the tires from rubbing inside the wheel well.
Again, for my money I can not say enough good about America's tire. I will take my car to them (Discount Tire here) for a rotate and balance every 5000 miles and they will do it for free. They know that is where I will buy my replacements when the factory installed originals wear out.