Who's good with wheel measurements?

I'm going to be ordering some new 15x8" wheels from Summit/Jegs/4WheelParts sometime in the next couple of weeks when I get money back from school.

I've ran into a small problem. The style of wheel I'm looking at is the Cragar Soft 8 pattern in black.

Summit carries both the Cragars and a Soft 8 copy by U.S. Wheel. The Cragars are only offered in a 4" backspacing, whereas the U.S. Wheel version is offered in a 3.75" backspacing. The Cragars are $36.99 each and the U.S. Wheels are $54.99.

Jegs carries the Cragars too... can't remember the price, but again, they're only offered in 4".

4WheelParts carries Rock Crawler's version of the Soft 8 and they're around $52.99 each, but they're offered in 3.75".

I'm not sure what the backspacing is on my factory 15x7s, but I'd like to get an idea of how much difference there will be between my current stance and my future stance if I were to get the 3.75" or the 4.00". I'm currently running 255/70/15s, but I plan on replacing them with either 31x10.50s or 32x11.50s along with a TT/Shackle/AAL. If I keep my stock suspension, is there a chance of fitting 31x11.50s without rubbing? I really wish I could find some 3.25" or 3.5" BS wheels...

 

[Dan Whitaker]

I belive the factory wheels are 3.75" back space. If you were able to find 3.25" or 3.50" back space it would be alot harder on the hub assemblies.

The 4" back space is for Heeps and will move the wheels in too far & could cause rubbing.

 

[X6StringerX]

Wouldn't a 3.5" BS on a 15x8 wheel put me pretty close to 3.75" BS on a 15x7?

I may have that totally wrong.

The more I look at wheels, the more I'm thinking of getting some black Daytonas with the artificial beadlock. I'm gonna do more research and see what exactly is available in black with 3.5-3.75".

US Wheel makes a two-tone black/polished modular that looks pretty good. I tried Photochopping them on my X, but I just can't get it to look real. I need to find someone with PS skills...

 

[Lt.Jim]

Your factory wheels have a 4.5" back space. A31x10.50x15 should fit on the craiger soft 8 with the 4" bs. I have not seen a tire offered in a 31x11.50x15 but would assume rubbing issues with a 32x11.50x15 and stock suspension. With a TT,AAL and shackles you might fit a 32.

Check Dead Link Removed

 

[Dan Whitaker]

Pro-Comp, Kumho, Mickey Thompson, Interco all make a 31x11.50x15

 

[Lt.Jim]

Pro-Comp, Kumho, Mickey Thompson, Interco all make a 31x11.50x15

I stand corrected!
I knew there were some 31x12.50s but had not seen the 11.50s. I would guess, but may be wrong, that a 31x11.50x15 on a 15x8 rim with 4" of bs would fit pretty well on a tt,aal and shackles?

 

[Dan Whitaker]

I did goof on the Pro-Comp. They are 31x12.5x15 not 31x11.50x15.

It seems like BF Goodrich makes a 31x11.50x15 A/T but I'm not certain.

Personaly I would go 32x11.50x15's becuase they will be cheaper as they are a more common size.

 

[X6StringerX]

I was only going to go with 31x11.50s if I didn't have to do the TT/Shackles/AAL in order to fit them. If I go through all of that trouble, of course I'll go with 32s!!!

So my tires should set out a good bit more with 3.75 or 3.5 BS. I thought the factory wheels were 3.75 too...

 

[Lt.Jim]

I can say for sure they are 4.5 because I just measured mine. I have the stock deer hoof 15" wheels on mine.
Yes they will set out more because of the less bs and a wider tire. You may want to check your local laws they may require fender flares if the tires stick out much further then the fenders.

 

[X6StringerX]

Thankfully, our law system is pretty easy on modded vehicles. Maybe I should say rarely enforced...

So, do you guys think the 4" BS on a 15x8 would be OK or should I try to get 3.5-3.75" BS?