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Proper backspacing/offset for 35’s with no bulge

Waiting

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To Waiting. I'm trying to get this right so i need your help. I'm looking to put 17 x 9 on my unlimited sport. The tires that I'd like to get would be nitto ridge grapplers 315 70 17. I have the mopar lift, i dont want to stick outside the fender more then 2" would i need a offset of -12 ? Any and all help would be greatly appreciated. Thank you
9” wise with -12 offset would kick the tie out 2.74 inches out further than a stock 285
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TroyBoy

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At 0:51 in this video, you can see what 17x8.5" wheels with +10 offset and 285/75 (34x11.50) tires look like. As you can see, there's some tread sticking out.

If you go 12.50 width, then you're adding another half inch of tread outside the flares. So that's why I said you really need to stick with +25mm or greater positive offset if you need to keep the rubber inside the flares.

Problem with this video is it is not a Rubicon. Rubicon axles are 1.5” wider. I have 315/70/17 duratrac tires on stock wheels on my rubicon. The tread is under the fender but the sidewall bulges past the fender. That is with a 45mm offset on the stock wheels. I think you’re screwed if you want that size of a tire on a rubicon and need the tire sidewall to be inside of the fender. Others have suggested a skinnier tire which may be your only solution.
 

Waiting

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Problem with this video is it is not a Rubicon. Rubicon axles are 1.5” wider. I have 315/70/17 duratrac tires on stock wheels on my rubicon. The tread is under the fender but the sidewall bulges past the fender. That is with a 45mm offset on the stock wheels. I think you’re screwed if you want that size of a tire on a rubicon and need the tire sidewall to be inside of the fender. Others have suggested a skinnier tire which may be your only solution.
I think agree. Pics of the set up? How much room remains on the inside of the fender?
 

TroyBoy

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I think agree. Pics of the set up? How much room remains on the inside of the fender?
Well I do have a 2.5” lift and I’ve flexed it pretty hard without any rubbing. I ran those tires without a lift and it was fine around town. I don’t have pics showing the amount the tires stick out past the fenders but I can take some tomorrow.
 

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Waiting

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This will help.
www.rimsntires.com/specspro.jsp

Put your OEM spec tire on the left and play with different configurations on the right. This calculator tool will help you decide.
^^^Good resource! Playing around with the specs, and assuming a 45mm offset on the OEM 7.5" wide wheels, at 315 tire will require a 8.5" wide wheel with approx 30mm offset to retain the OEM inner clearance but will poke the tires an additional 1.2" outside. A 9" wide wheel would require a 35mm offset on a 315 tire to retain the OEM inner clearance.
Good luck finding any wheels with specs that approximate what is required
 

Sting_Rubi

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Sorry I should have given more info. I have a JLUR, but not sure I want to chance mounting a 12.5 width tire on the stock 7.5 rim (nor do I know who would even mount for me). What I’m trying to find is a 17/18.5 rim with the proper offset for 35’s with no bulge. What you have is exactly what I want for a look, but just an 8.5” rim.
Guy at work put 35x12.5 on his factory Rubi wheels.. Looks exactly how you would want it.. I'll try to get a profile picture on Wednesday when I get back to work.. (His is the firecracker red btw)

IMG_6529 (2).jpg
 

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I think you can do it seeing that the Rubi axle is a little wider than the Sahara.
 

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TroyBoy

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Here are my 315/70/17 duratrac tires on my rubicon with stock wheels:
FDAC327E-682E-411A-81B6-D17B5791B1CC.jpeg
226D0F9E-6C42-4BF7-99F6-B2F8CD117340.jpeg
64C8186A-A66B-48D9-8129-610250C56262.jpeg
EC9FB1A6-82A7-4221-A550-BAB250F5EE41.jpeg
 

TroyBoy

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Looks great...How do those tires ride compared with stock ko2's? Do you have a lift?
Well it’s been a while but I think it was just as good as the stock tires. I have a 2.5” RK lift.
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