Hi. I need to do some measuring but I'm in a similar boat. Here is my best estimate.

I bought a CJ7 that has 1986 wide track axles (D30 and D44) open diffs with 3.31 gears and 35" tires.
Then I found a older CJ7 with the same axles but 4.56 gears and ARB air lockers. So I bought it. Planning to swap the axles and sell the second Jeep.
Only to find that the 'new' older Jeep has narrow track axles. I'm in the process of swapping the rear axle and noticed the difference. About 5" shorter.

Based on my axles and the 5" difference, I'd say that roughly you need to push your tires out about 2" to simulate a wide track look.

Doug

 

Narrow Track CJ:

Backspacing: Maximum 3.75 Inches - Although you might be able to go to 4 inches depending on tire width.

Center Bore Hole Diameter: 4.25 Inches

Lug Pattern: 5 on 5.5 Inches

I recommend a 15X8 wheel

Good luck with your CJ!

 

This probably describes the wheels you currently have.

 

The front axle track is a little wider than the rear so the rear tires will be a little tucked in. My post may have described your current wheels but this size wheel - 15X8 and tires - 31X10.50 - is a good size for a stock suspension CJ.

 

I'm looking to push the wheels out a little bit more. What offset can I go with using a 15x8 or even a 15x10? Can you put a 31/10.5/15 tire on a 15x10 rim?

 

Here is a photo of my '79 CJ5 - factory 15X8 white spoke wheels with 31X10.50 tires.

I use no wheels spacers. Notice how the rear track is less than the front. You can see
the front tire is out a little more than the rear.

 

3.75 is normal back spacing for factory 15x8's. Rear track width is 50" and front is 51.5. What also makes the front tires stick out further (at the top) is the camber angle. FWIW

 

Well you could get a 15X8 wheel with 3.5 inches or 3 inches of backspacing - toward the inside (suspension). That would give you more toward the outside ( street side).

I don’t think it would be a good idea to mount a 31X10.50 tire on a 15X10 wheel.

 

You need to see if the wheels you want to run, are manufactured with the BS or OS you desire. That is the first thing I would do.

 

What is "BS or OS"?

 

Use this website to research what you want or need. It is the best site I know of for determining tire size before you buy the tires. All you have to do is figure out what you have before you start, and then you can input different tires/wheels in various sizes and dimensions.

https://tiresize.com/converter/

 

Hurricane4,

That looks just like my #4 1978!

It looks really nice!

----JEEPFELLER

 

Thanks JEEPFELLER. 16,000 original miles & original Cumberland Green Metallic paint.

 

Thanks 80cj. The top is a Whitco RoughRider.

On the soft top instructions the date 7/87 was written on the first page. So this top is not original to the Jeep.
It does have rubber door seals and a rain gutter above each door.

The top is still in great shape. From what I can gather on the net Whitco went out of business in 1991.

 

I don't wish to throw this thread off on a tangent but will say that I think Whitco made the nicest styled tops for late CJ-5's. I always keep my eyes open for new old stock tops but they are very rare now.

 

Interesting read on the Whitco company:

http://www.ewillys.com/2021/09/09/thor-products-white-automotive-whitco/

 

Great link, I grew up in Colorado Springs in the 1970s-80s and drove by Whitco plant almost weekly. They were very close to a Timken plant and just a few miles from Western Forge, who made Craftsman (and other brands) hand tools.

None of them remain in Colorado Springs any longer.

It's interesting that the the big three top makers of the 60s-90s were in Colorado. Only Bestop remains, but they moved their production to Mexico several years ago. I guess the remnants of Kayline still exist in a company in Denver called B-D Company (coincidence that Bestop used to be Bestop-Dualmatic or BD??). They still make tops for Scramblers, Commandos, and some Scout models.

 

So the real question is how much backspacing can I get away with using a 15x8 wheel (3.5 or 3 or 2.5 or 2)?

Does anyone here have a picture of what a 15x8 wheel w/ 2" backspacing?

The tire will be some type of All Terrain tire 31/10.5/15.

Thanks

 

Good explanation of Wheel Backspacing and Offset here:

https://news.classicindustries.com/...acing-and-offset/?gclid=EAIaIQobChMI64Tv4qOi9AIVmP6zCh0KqwSKEAAYAyAAEgKedPD_BwE

 

BS= backspacing
OS= offset

What type or style wheels are you talking about? It makes a difference as far as availability is concerned.

BS & OS are similar, but very different. Backspacing is measured in inches, offset is measured in MM’s, but there is more. See the diagrams below.

If you put 15x8 wheels with 2” BS on a NT CJ-7, it would look similar to a WT CJ-7 with OEM 15x7 wheels. This is assuming they both have the same size tires. I don’t know if a 15x8 wheel with 2” BS is available, because you haven’t said what style wheels you have or want to use.

WT CJ-7 axles are about 4.5”- 5” wider than NT axles.

When measuring an axle width, it is normally measured Wheel Mount Surface (WMS to WMS). See the diagram below, it is dimension X.

1976 to 1981 CJ-7’s with NT axles are front- 51.5" rear- 50" NT (WMS to WMS width)
1982 to 1986 CJ-7 front- 55.8" rear- 55" WT (WMS to WMS width)

I’m not sure what the BS is on the 15x7 OEM wagon wheels is???? I suspect 3.5” or 3.75”.

Maybe someone will chime in and let us know. (I wish we had a sticky on CJ wheels, it would come in handy)

Aftermarket wheels are normally available with a wide variety of BS & OS, among other dimensions.

OEM CJ wheels are only available in limited dimensions, like 15x5, 15x7 and 15x8. Wagon wheels are 15x7 & 15x8, as far as I know. There are probably others, that’s why I wish we had a sticky.

 

BS= backspacing
OS= offset

What type or style wheels are you talking about? It makes a difference as far as availability is concerned.

BS & OS are similar, but very different. Backspacing is measured in inches, offset is measured in MM's, but there is more. See the diagrams below.

If you put 15x8 wheels with 2" BS on a NT CJ-7, it would look similar to a WT CJ-7 with OEM 15x7 wheels. This is assuming they both have the same size tires. I don't know if a 15x8 wheel with 2" BS is available, because you haven't said what style wheels you have or want to use.

WT CJ-7 axles are about 4.5"- 5" wider than NT axles.

When measuring an axle width, it is normally measured Wheel Mount Surface (WMS to WMS). See the diagram below, it is dimension X.

1976 to 1981 CJ-7's with NT axles are front- 51.5" rear- 50" NT (WMS to WMS width)
1982 to 1986 CJ-7 front- 55.8" rear- 55" WT (WMS to WMS width)

I'm not sure what the BS is on the 15x7 OEM wagon wheels is???? I suspect 3.5" or 3.75".

Maybe someone will chime in and let us know. (I wish we had a sticky on CJ wheels, it would come in handy)

Aftermarket wheels are normally available with a wide variety of BS & OS, among other dimensions.

OEM CJ wheels are only available in limited dimensions, like 15x5, 15x7 and 15x8. Wagon wheels are 15x7 & 15x8, as far as I know. There are probably others, that's why I wish we had a sticky.

Yes, I understand the backspacing part of it. I just didn't know how much of a backspacing I could go? I don't need anything fancy. I just want to push out the wheels a little more so it looks more like a jeep should.

I was looks at these because of the 2" backspacing. And you are right these are on back order. Is that a popular wheel size and backspacing???
https://www.summitracing.com/parts/clm-5375855-2

 

Great post Ax.

 

Technically those wheels will fit your CJ. Now the fine print:

“ Notes:
These wheels are not DOT-approved.
Bart Wheels Economy Modified Standard Weight Black with Purple Stripe Wheels
Bart Economy Modified Standard Weight black wheels with purple stripe are designed for use in sportsman, IMCA modified, and WISSOTA modified classes on cars up to 2,800 lbs. They are built with a .221 in. commercial-quality steel center and a .135 in. thick roll-formed rimshell for strength. They're available in several sizes and backspacings to meet class rules and track styles.”

 

Technically those wheels will fit your CJ. Now the fine print:

" Notes:
These wheels are not DOT-approved.
Bart Wheels Economy Modified Standard Weight Black with Purple Stripe Wheels
Bart Economy Modified Standard Weight black wheels with purple stripe are designed for use in sportsman, IMCA modified, and WISSOTA modified classes on cars up to 2,800 lbs. They are built with a .221 in. commercial-quality steel center and a .135 in. thick roll-formed rimshell for strength. They're available in several sizes and backspacings to meet class rules and track styles."

What does it mean if the wheel is not DOT approved? Does that mean they are illegal to use on the roads. Are there going be issues with balancing them? Will they break after awhile?

So next question is what is a good wheel that is DOT approved? Like I said I want something that has an offset of about 2" to 3" inches that is a 15x8 5x5.5 bolt pattern.

Thanks,

 

DOT - Department of Transportation

 

2.5 inch backspacing:

https://www.summitracing.com/parts/usw-70-5855r

 

Wow, You found the solution at a great price. Good job!

So the real question is how much backspacing can I get away with using a 15x8 wheel (3.5 or 3 or 2.5 or 2)?

Does anyone here have a picture of what a 15x8 wheel w/ 2" backspacing?

The tire will be some type of All Terrain tire 31/10.5/15.

Thanks

To answer this question, let's compare those numbers to an OEM wheel. The stock 15 x 8 wagon wheel (that I have) has 4" BS. All of the ones you listed above are less than 4", so the wheel and tire are pushed out away from the frame & suspension. This indicates they will work, or fit without interference.

 

Another wheel - 2.5 inch backspacing:

http://www.summitracing.com/parts/usw-78-5855r

" Reverse offset wheels have less backspacing and more dish, which may interfere with some brake and wheel opening configurations."

 

My first concern with pushing the wheel out is bearing wear. However the OP will be running a reasonable size tire - I think he said 31X10.50. In that case it probably will be OK - but keep in mind you are modifying geometry from factory specs. Also another issue is the fact extra wide fender flares will be needed to cover the “pushed out” tire/wheel combo. Good luck with it!