ok i need...not want, i need new wheels.  I'm looking at pro-comp xtremes.  i'm going to get the RRO 4inch lift and 31's before summer.  What would be the dead on perfect back spacing for this set up?  Also, i do not want to cut or modifiy the body.
I currently run 235 BFG A/T's with no lift and will continue to till summer....just in case you must know.

With a Tracker, right?

What is the smallest backspacing the wheel comes in?  prolly 3.25-3.75???

I would go for the 3.25 if they have it.. you are going to be rubbing on your frame with any more.. IMO...     

for a 7" wide rim I'd say 3.5" and for an 8" wide rim- 3.75"

ok i found the perfect rim and i ordered it in 15x8.  but they were not sure what back space it was.  All she could tell me was it's got negative 12 offset.  Anyone know what that comes to....I was hoping for 3.75 back spacing.

Well, it can get a little confusing.

backspace is the measurment from the inside lip of the rim, to the wheel mounting surface, and offset is the distance from the CENTER of the wheel, to the wheel mounting surface, or the centerline wheel "offset" from the wheel mounting surface.

A standard 8 inch rim is about 9 inches wide, lip to lip, so a 0 offset on a 8 inch rim is usually about 4.5 inch backspacing... (confusing huh)

SO,  12 mm offset on a 8 inch wheel, that measures about 9 inches would be about half and inch either way, depending on the offset being negative or positive, I am guessing you are going to end up with a 3.75-4.00" inch backspace.. might be just right, or you might be in for frame rubbing, just one way to know for sure!!  Slap them puppies on!

-12 on an 8' rim is 4" backspace.

So...I went with 32x11.50 SSR's on 15x8 AR 172's with 3 3/4" BS.

Think I'm gonna have issues?  Iknow, I know...bolt em up! I gotta get off my arse and put the lift in first!

 

I think you will hit the frame with those. You can adjust the steering stops but you will lose lock.

well your right i did some research and they are in fact 4.00 BS.  but i'm just running 235/75-15's right now so it should not be a problem i would guess.  I just hope it doesn't stick out to freakishly looking.  But i plan on a 3 inch lift next so that may balance it out later.  I'm really liking the Boondox 3 inch lift...great price.

8 inches may be a bit wide for 235's. Rumor has it that a narrower wheel works better when you air down.

I agree that 8" is too wide for a 235. I see that you are looking at 31's down the track. If they are going to be 10.5 wide then I would stick to 7" rims as they will suit both sizes and yes the narrower rim is better for when you air down as it tends to hold the bead better IMHO.

Yeah i was seriously sweating the 8 inch/4.00 BS issue too.  I thought it'd be too much and i'd have rubbing issues and it would look totally horrid.  I was wrong the wheels actually fit great, i only get a little rub on the passenger inner wheel well plastic trim on sharp right turns.  That's it!  and it looks good...they don't stick out too much (Click on the first picture)  I love them so far but the test will however be if you guys are right on the airing down.  I'll let you all know when i get to that point.





Thanks again guys for all the info