Ok let me make sure I understand this. The truck above has a wheel w/ 6.5" of backspacing. If the backspacing were reduced to 4.5" on the same width wheel then it would stick out of the wheel well another 2" correct?

 

Correct.

 

backspacing is how far the hub or whatever its called is away from the backside of the rim i believe

 

This is how you measure backspacing.

 

thats what i was trying to say but a pic is better