I'm getting a pair of bullitt wheels for my black stang.
20x10's in the back
http://www.americanmuscle.com/black-...8x9-18x10.html

20x9's in the front
http://www.americanmuscle.com/verde-...tt-wheels.html

The only problem is I'm new to this and I don't know what the best tire size is for these wheels. Any help would be great, thanks!

 

If you scroll down on the page it tells you the best tire fitment

 

are you getting 18's or 20's? what you mentioned and what you sent links to don't match. I'm looking at 20's, for the front I'm going with 275-40-20's for the front and for the rear I'm going with 305-35-20's.

here's a tire size calulator to play with, it'll help make sense of the tire sizes...
http://www.discounttiredirect.com/di...foTireMath.jsp

just put in your stock tire size and play with the sizes until they're pretty close to the same speed where it shows what the speedo would read, then you know the overall diameter is close enough.

 

so r they 18's or 20's?