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Discussion Starter #1
Ok on a 2500 with a 6in lift. What backspacing would i need to fit 37x13.5x17 tires. I mean obviously they wont be all the way under the truck. I want them to stick out a lil, like maybe 50/50 or maybe ever 2/3s under and 1/3 out. I obviously dont want them to rub. and it would be on a 17x8.5 or 17x9. anybody know anything about wheels as far as backspacing and offset, that could help me pick some wheels out. thanks
 

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kstompaint
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Mine area this:
22x9.5
0mm Offset
130mm centerbore
not sure on the backspacing
with 37x13.5's

If that's any help.
 

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If I remember right, a 0mm offset means the wheel mounting surface is in the exact middle of the wheel width. Therefore, a 0mm offset on a 9.5" rim would result in a 4.5" backspace.
 

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Discussion Starter #4
kstompaint said:
Mine area this:
22x9.5
0mm Offset
130mm centerbore
not sure on the backspacing
with 37x13.5's

If that's any help.

Do the tires rub at all
 

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kstompaint
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338 Posts
At first they did but it was because my aftermarket bumper just needed adjusted a bit. Now they dont. My 37x12.5 MTR's on my stock 17" wheels rub slightly on the arms at full steer.
 

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btolenti said:
If I remember right, a 0mm offset means the wheel mounting surface is in the exact middle of the wheel width. Therefore, a 0mm offset on a 9.5" rim would result in a 4.5" backspace.
Welcome to the site!

Actually, it is 5.25" backspace on a 9.5" rim for 0 offest.

Here is an easy way to remember backspacing:

- Take the rim width (9.5" in this case)
- Divide that by 2 (4.75" in this case)
- Add .5" to that result, then the wheel offset (0 in this case - you will have to convert mm to inches if there is offset), and you get the wheel backspacing (5.25" in this case)
 

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wesshipman said:
Ok on a 2500 with a 6in lift. What backspacing would i need to fit 37x13.5x17 tires. I mean obviously they wont be all the way under the truck. I want them to stick out a lil, like maybe 50/50 or maybe ever 2/3s under and 1/3 out. I obviously dont want them to rub. and it would be on a 17x8.5 or 17x9. anybody know anything about wheels as far as backspacing and offset, that could help me pick some wheels out. thanks
If you are going to run a 8.5" wheel and want 2/3 under and 1/3 out, you will want to find one with about 5.75" of backspacing (or +25mm offset)

If you are going to run a 8.5" wheel and want 50 under and 50 out, you will want to find one with 4.25" of backspacing (or -12mm offset)

If you are going to run a 9" wheel and want 2/3 under and 1/3 out, you will want to find one with 6" of backspacing (or +25mm offset)

If you are going to run a 9" wheel and want 50 under and 50 out, you will want to find one with 4.5" of backspacing (or -12mm offset)

Hope this helps!
 

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blk_fxstc said:
Welcome to the site!

Actually, it is 5.25" backspace on a 9.5" rim for 0 offest.

Here is an easy way to remember backspacing:

- Take the rim width (9.5" in this case)
- Divide that by 2 (4.75" in this case)
- Add .5" to that result, then the wheel offset (0 in this case - you will have to convert mm to inches if there is offset), and you get the wheel backspacing (5.25" in this case)
Thanks for the welcome! I am a recently converted Dodge owner....used to be a Ford guy...now I have a 2500 Ram with the Cummins....no looking back for me. :rck:

Yeah, my division is a bit off apparently. Why the addition of 0.5" to calculate backspace? Any real reason, or was that just some figure someone came up with? My only though would be to account for rim thickness, but 1/2" seems like a bit much. :dunno:
 

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btolenti said:
Thanks for the welcome! I am a recently converted Dodge owner....used to be a Ford guy...now I have a 2500 Ram with the Cummins....no looking back for me. :rck:

Yeah, my division is a bit off apparently. Why the addition of 0.5" to calculate backspace? Any real reason, or was that just some figure someone came up with? My only though would be to account for rim thickness, but 1/2" seems like a bit much. :dunno:
I am an ex powerstroke owner also..... :D

For example, a 9" wheel is measured from inside the flanges on the wheel. The backspace is measured from the outside of the flange to the hub mounting point. 0.50" is the industry standard for the flange thickness I think, even though some are more or less than this.

See the attached link for some additional information and a chart of backspacing and offset.

http://www.rsracing.com/tech-wheel.html

Enjoy!
 
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