So before anyone hounds me for not doing a search, let me assure you I reviewed more than 25 pages worth of 20 threads looking for answers on what the acceptable backspace is for 15x8's on a JK. Allow me to demonstrate how the search was not necessarily useful. For instance this one individual, (forgive me usmcdoc14), in 2 different threads said he has 2 different BS's 4", and 3.75". Now someone explain how information like this will help a guy determine what range of BS can be used on wheels.

https://www.jk-forum.com/forums/show...24&postcount=4
"I have your typical black "D" window style in 15x8 with 4" backspacing and they fit fine."

https://www.jk-forum.com/forums/modified-jk-tech-2/rim-wheel-thread-10575/
"I am running 15x8 Cragar "D" window (the same as US wheel and others) with a 3.75 backspacing. No clearance issues at all."

Not trying to throw stones before I'm even known, but what's the answer on what BS is needed, optimal, or acceptable on a 15x8 wheel for a JK?

Thank you.

Sorry usmcdoc14

 

The answer is it's not all about the backspacing on a 15x8 inch wheel. You will have to decide what wheel you want, then see if anyone here has any experience with it in that size and backspacing.

It will probably need to have in the range of 4.0", 3.75", or 3.5" backspacing. I have personally used and verified two different 15x8 wheels, the Cragar Soft 8 15x8 with 4.0" backspacing, and the ION 170 15x8 with 3.5" backspacing.

If noone has tried a wheel you want to use, you are going to have to buy one and put it on the hub to see if it will clear the caliper. There's no definitive backspace for a 15" wheel, it's all about how the wheel is made. One 15x8 with 4.0" backspacing may work fine, another 15x8 from a different manufacturer may not.
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I'm pretty sure USMCdoc has more than one Jeep, also.

 

Thanks a lot for your help. I'm looking at Cragar as an option so thank you for that confirmation. In trying to find a good deal around the net, a lot of places don't carry that so I wanted to see my tolerances - one place only had 3.75" with the bolt pattern and size so I wanted to see if that was okay too, again, as I search for a good place to buy.

I am not sure if it is against the forum rules here, given the sponsors, but does anyone know a good place to buy wheels and tires. I will be sufficiently vague to say right now I am looking at wheels on "summit" and tires on "4wd". Are you aware of any great places, especially ones that might be willing to mount and balance for a small fee?

Thanks again.
Ha, no worries, I wasn't trying to say he's lying.

 

i'm looking at getting the Pro Comp 7023 18x9.5" wheels. they have 4.75" backspace. anyone know if i will need to add spacers?

 

That really depends on how wide of a tire you plan on running. But, assuming you will be running a standard 12.50 wide tire, you will be just fine.

 

thanks! right now i'm leaning toward in the 35x12.5 nitto mud grapplers.

 

should 37x12.50R-15 with a Cragar D Window Wheel 15inx8in with 4.0" of BS fit the JK in terms of backspacing (and assuming there's enough lift obviously)?

I know you said you ran that size Cragar Soft 8 with 4.0" BS but I just want to make sure that a 12.5" wide tire isn't too wide and that it won't be rubbing on the coils or something...

thank you again for your help

 

Yup. Factory BS is 6.25" and so 4" should push your tires out more than enough to clear 12.50's (less BS = tire sticking out more / more BS = tire tucked under the flares more).

 

my bad. regardless, I'm sure he has an explanation...
thanks, got it!