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Discussion Starter #1
Alright so I hate to admit I that I need to resort to the "what do I need thread" but here I am.

I've got a set of Cooper Discoverer STT Pro's in 37x13.5x18 that I'll be taking off my wife's Ram soon. I thought I would be able able to run them on the truck but I'm having too many issues ranging from clearance problems to acceptable PSI on a 2500 so I'm going to suck it up and pull them. I'm hoping to able to sell them, however I'm exploring the option of maybe running them on my JK.

That said, this is my set up currently. I'm running a full Synergy 3" stage 3 suspension system with stock fenders on my Rubicon. If I wanted step and run the Coopers in 37x13.5x18 on my JK what backspacing would I be able to get away with and not have rubbing with an 18x9 rim? I've read that I "should" be able to get away with -12 offset/4.5bs, but can anyone confirm that or will I need more (or is that less when go further out).

Thanks in advance...

Kevin
 

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You should be looking in the 3"-3.5" back spacing range. Your wheel width will also affect your clearance as well as the actual width of the tire which is most likely not 13.5" A 4.5" bs wheel is good for a 35"x12.5" tire not a 37"x13.5" tire.
 

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With 18x9 wheels and 3.5" (5" wheel backspace plus 1.5" spacer)backspace I can just lightly touch the frame on the rear of the tire and just touch the sway bar with the front of the tire. I run the same STT Pro 37x13.5-18 as what your talking about.
 

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OP, do you wheel the jeep?

If you wheel it, Dirtman has your answer. The issue is full stuff and lock..with just a 4.5" backspace you will be contacting your grill, sway bar arms, etc. You will want to either cut your stock fenders or go with an aftermarket flat fender...or bump stop a lot more to stay out of the full stock fender flare

You should be looking in the 3"-3.5" back spacing range. Your wheel width will also affect your clearance as well as the actual width of the tire which is most likely not 13.5" A 4.5" bs wheel is good for a 35"x12.5" tire not a 37"x13.5" tire.
If you lightly wheel it or just DD it they you can get away with what is a 4.5' backspace that Larry mentions here

With 18x9 wheels and 3.5" (5" wheel backspace plus 1.5" spacer)backspace I can just lightly touch the frame on the rear of the tire and just touch the sway bar with the front of the tire. I run the same STT Pro 37x13.5-18 as what your talking about.
 

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OP, do you wheel the jeep?

If you wheel it, Dirtman has your answer. The issue is full stuff and lock..with just a 4.5" backspace you will be contacting your grill, sway bar arms, etc. You will want to either cut your stock fenders or go with an aftermarket flat fender...or bump stop a lot more to stay out of the full stock fender flare



If you lightly wheel it or just DD it they you can get away with what is a 4.5' backspace that Larry mentions here

5" BS + 1.5" spacer equates to 3.5" BS, not 4.5" as you typed above. I'm at 3.5" and lightly rub, not enough that I hear it, but enough that I see the polished steel. I do wheel it and stuff it, it's not a DD at all. I have another Jeep that is my DD.
 

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OP, do you wheel the jeep?

If you wheel it, Dirtman has your answer. The issue is full stuff and lock..with just a 4.5" backspace you will be contacting your grill, sway bar arms, etc. You will want to either cut your stock fenders or go with an aftermarket flat fender...or bump stop a lot more to stay out of the full stock fender flare



If you lightly wheel it or just DD it they you can get away with what is a 4.5' backspace that Larry mentions here

5" BS + 1.5" spacer equates to 3.5" BS, not 4.5" as you typed above. I'm at 3.5" and lightly rub, not enough that I hear it, but enough that I see the polished steel. I do wheel it and stuff it, it's not a DD at all. I have another Jeep that is my DD.
You're right. I had the OP's 4.5 BS on my mind when I read your comment about light rubbing and didn't do the math on yours. 3.5" that you have is definitely usable.
 

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You're right. I had the OP's 4.5 BS on my mind when I read your comment about light rubbing and didn't do the math on yours. 3.5" that you have is definitely usable.
I'm sure that my unit bearings will live a short and sad life :crying:
 

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Yeah, the Jeep does get wheeled, though not as much as I would like.



I'm gathering that it's not going to be worth my while to dick around trying to make the tires work on my Jeep since the biggest issue I'm going to run into is finding rims with enough backspacing.


Oh well, thanks for the info everyone.
 

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I'm sure that my unit bearings will live a short and sad life :crying:
I have run 4.5' BS wheels on 1.5" wheel spacers for quite some time and have not had issues with unit bearings....rear flanges have not been so good to me though. Bent both sides, at different times, on stock axle shafts. Also bent both sides, again at different times, on Ten Factory Chromo shafts.
 

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Yeah, the Jeep does get wheeled, though not as much as I would like.



I'm gathering that it's not going to be worth my while to dick around trying to make the tires work on my Jeep since the biggest issue I'm going to run into is finding rims with enough backspacing.


Oh well, thanks for the info everyone.
run a wheel spacer to get you to the BS you want
 

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Discussion Starter #11
run a wheel spacer to get you to the BS you want
Like I said, it's not worth my while. If I have buy rims, I'm buying rims that are going work with the combination I'm running. It's not worth it to me to have to buy rims and wheel spacers just so I can try and reuse the tires I'm taking off my wife's truck.

Besides, with the unexpected expense for the new tires for her truck I just going to focus on trying to unload the 37" Coopers to hopefully offset what I'm racking up for the new tires.
 

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Like I said, it's not worth my while. If I have buy rims, I'm buying rims that are going work with the combination I'm running. It's not worth it to me to have to buy rims and wheel spacers just so I can try and reuse the tires I'm taking off my wife's truck.

Besides, with the unexpected expense for the new tires for her truck I just going to focus on trying to unload the 37" Coopers to hopefully offset what I'm racking up for the new tires.
for some reason I thought you already had 4.5" BS wheels
 
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