Okay, I have a '99 cobra with a live axle out of a '96 cobra. So the axle is about 1.5" shorter than a '99 GT live axle. I want the rims to stick out a little more than they do now, plus I want to put on a wider tire as well. (I was thinking about going with the 315/35/17 Nitto Drag Radials). I am not sure if the 10.5" rim is going to fit on my car. I e mailed performance wheel out let and they told me that the backspacing on this rim is 6.8". I have no clue what backspacing means or how it applies. So if anyone could offer me some insight as to if these rims will fit my car or not, that would be greatly appreciated.