backspacing??? offset?
 

i am going to be ordering some soft 8 wheels online and i dont fully understand the backspacing and offset. can someone explain what these mean? and i want mine to stick out alittle bit i think it looks better. i will have a 3" lift with 31s... any advice?

Your 31s are typically 10.50 wide. On an 8" wide rim you will want it to have a 3.5 - 4" backspacing. If you want them to stick out more, lean more toward the 3.5" backspacing.

Backspacing is the ammount of space between the mounting surface of the rim and the inner lip of the rim. the smaller the B.S. number is the more your tire will stick out. I dont go by rim offset. but thats just me.

in a nutshell, an 8 inch rim with 4 inch backspacing has 0 offset.
take that same 8 inch rim with 3.75 inch backspacing, and you have .25 inch negative offset. if it had 4.25 inch backspacing, it would have .25 inch positive offset.

a stock 7 inch wide rim usually has 5.25 inch backspacing, so it would have 1.75 inch positive offset.

More specifically, a rim typically is about 1 inch wider from edge to edge than listed - mostly because the listed amount is where the tire seats, and the total width has a couple layers of rim beyond the seating surface. Dealing in backspace is typically much simpler. As stated, you will want 3.5" to 3.75" backspace if you want them sticking out a little. Mine had 3.5" on 31's back in the day, and it was sweet. If the wheels you want come in "offset" numbers only, you will need to calculate it based on the width of the wheel. Plus, they almost always do it in millimeters for extra fun. To get 3.5" backspace on a 8" wide, you need about -25mm offset. For 8.5" wide, -32mm. For 9" wide, -38mm. For 9.5" -44mm, and for 10" -51mm. Make sure it is negative, as positive numbers will be going the other direction of wheel center, and will be the opposite of what you want.