Defleshed said:
dont get wheels any bigger than 8.5 for the fronts.
What is your basis for this statement? I have Ford Racing 2000 Cobra R's which are 18x9.5 with 275/35/18's on all four corners and I have absolutely no issues with them at all. I also have the Ford Racing "C" springs with no isolators and I still have no issues.
What you have to pay attention to when buying a wheel and tire package is the offset of the wheel and the width and aspect ratio of the tire compared to the stock tires. Your offset will determine how wide you can go with your wheels and tires. The aspect ratio determines the circumference of the tire based on the width of the tire.
So take my 275/35/18's for example:
Width is 275mm
Aspect Ratio is 35% of the width (in other words the sidewall height is 35% of the width in mm)
From this data you can figure your circumference.
275 X 0.35 = 96.25mm
Convert 96.25mm to inches because your wheel size is in inches (18 for this example)
96.25mm = 3.789 in.
Figure your radius from the center of the wheel to the outer edge of the tire
9 + 3.789 = 12.789
Circumference equals 2 X Pi X radius = 2 X Pi X 12.789 = 80.355 in.
Stock circumference is 80.679 in.
Ideal tire size is 275/35/18 because no other tire size will get a circumference this close to the stock circumference.