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Backspacing question


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3 inches on a 15x10 rim should do it for ya. I'm running 4 inch backspaced 16x 8's and clear 285's, (33.4x12.5) with about 1/2 inch to the control arm. If you still rub a little, throw a couple washers in behind your steering stops. If you go with anything wider than 3 inches, you'll be putting a LOT more stress on all your front end/steering components.

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I do plan on running a long arm set up (clayton is my fave so far) when i put all the lift and 4x4 parts on this bad boy, is that going to make a difference with rubbing the lowers? I keep hearing around 4-4.5 inches is real common backspacing, am i mistaken? Also if some one can post a pic or two of the 35's with a similar backspacing i would like to see what i am going to look like :D thanks all

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I don't mean to bug but how come i shouldn't run 8 inch wide wheels? Cause of the 15 inch dia. on the wheels? If i can run a 8 inch wide wheel what should the back spacing look like? I got schooled on how to measure backspacing from one of my tire buds and i think i can find a similar backspacing on a 8 inch wheel. Any ideas? Thanks Zag

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I only suggested 10 wide because you are running 35s. If you were running 33's, I'd run 8 wide, but on 35s, you'd be pulling the tire in an awful lot. If you can get a deal on 8 wide, you'd probably be ok, since you aren't running super wide 35s, but if ordering new, I'd spend the extra $ and go for ten wide. Either way, the backspace will measure the same, and I would run 3 inch either way.

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I see what you mean as far as 10 wide. As far as backspacing i heard today that the measurement starts with the width of the wheel and was divided. He even went to say you measure from the outside width ( 9" on a 8" wheel) of a wheel to start the backspacing measure? He might of been crazy but i don't know for sure :dunno:

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Backspacing is the measurement from the inside lip of the rim, to the hub. Hence, 3 inch backspaced rims, means that the hub of the wheel is 3 inches in from the back edge of the rim. Best way to measure, (easier Without tires), Run a straight edge across the backside of the wheel, and measure from the straight edge, to the inside of the hub. The measurement your buddy was talking about is the offset. (How far off center the hub is in the wheel)

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We've ran 35's on a 8" rim for years without issues (even airing down to 12psi without beadlocks). I personally wouldn't run a 10" wide rim as you pop the bead a lot easier.

 

With a 8" wide rim you'll want 3.5-4" backspacing with a 12.5" wide tire. Here is a photo for reference running 35x12.5 with a 15x8 w/3.75" BS.

 

100_1490.jpg

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I see what you mean as far as 10 wide. As far as backspacing i heard today that the measurement starts with the width of the wheel and was divided. He even went to say you measure from the outside width ( 9" on a 8" wheel) of a wheel to start the backspacing measure? He might of been crazy but i don't know for sure :dunno:

Backspacing is not the same as offset. Backspacing is the dimension from the wheel mounting surface to the inner flange of the rim. Stock for an XJ or MJ with 15x7 OEM rims is 5-1/4".

 

Backspacing does not take into account rim width or centerline. If you have a 15x10 rim and a 15x8 rim, and they both have 4" of backspacing, the 15x10 rim will extend OUT by 2 more inches. They will both be the same distance from the control arms.

 

That's for the rim.

 

If the inner flange is in the same position for both but the 15x10 has the outer flange 2" farther outboard, then obviously the centerline of the 15x10 must be 1" farther outboard than a 15x8. So now if you mount a 12.5" tire on each rim, the centerline of the tire will be 1" farther out with the 15x10 ... or the centerline of the tire will be 1" closer to the control arms with the 15x8, even though the inboard flange is in the same position.

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