Backspace and offset kind of work hand in hand. You only need one measurement when choosing a fitment for your truck.

• On a 9" wide wheel (for example), an offset of 19mm gives you 5.7" (147mm) backspace.
• On a 8" wide wheel, an offset of 19mm wheel will give you 5.2" (134mm) backspace.

If you can only get the backspace measurements of the new wheel, the most you can probably fit would be 6", on a 9" wide wheel. That 6" backspace would have an offset of 25mm.
But I'd definitely try to keep it at 5.5" to 5.7" on a wheel width of 9".

 

so would i be able to fit 17x9 wheels with 285/70R17 tires with my 2in leveling kit and blocks in the rear?

 

for some reason there was only two choices on the wheels im looking at it was 4.00" and 3.75" i believe

 

What was the width?

4" of backspace is an offset of -25mm on a 9" wheel. No way that would fit.

 

these are the wheels that you have to choose your backspacing
http://www.4wheelparts.com/Wheels/Bl...1638&w=2515-25

 

how about on a 17x8?

 

Yeah, offset of zero on the 17" x 8" wheel. No other options available for that one, I'd look for a different wheel.

 

would i be better off with these and then just finding tires that fit?
http://www.wheelsnext.com/wheels-rim...%7C%20Red.html

 

now i just found this.......SO MANY OPIOINS! i dont know what to choose
17x9 wheel size
Backspace 5.71
Offset = 18 mm

 

That's more like it, good fit there.

Take your time and pick the wheels that you really like, you're going to be stuck with them for a long time.
Don't rush it.