Wheels for a duster offset and backspace

famous bob said

I still don't understand why a person would worry about offset, the back space is what really matters for wheel fitment ,if the back space aint right , it wont work if ur pushing the limit on wheel/tire size.
I have to have a 3 1/2" back space with my rear end length, and tire / wheel combination, I could care less about the offset in mm measurements.???????

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The problem is, backspacing doesn't take into account the tire. Just because the wheel fits, doesn't mean it will with a tire on it.

With offset, I can get a fair estimate of how much room I need just by taking half the tire section width and adding/subtracting the offset. Pretty easy to figure out.

Backspacing really only comes into play when trying to figure out clearances for things like suspension parts. So, backspacing is pretty useless on the rear axle, but can be hugely important on the front suspension.

So, both are important, just depends on what you need to know.