Questions re use of 17x9 wheels on TJ/LJ and Necessary Backspacing with 35x12.50 Tires

Mr. Bills

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I am currently in the parts gathering stage for a manual hub conversion and installation of a Vanco 16" Big Brake Kit on my '06 LJ Rubicon.

The 16" brakes will preclude the use of most if not all 15" wheels unless I settle for less than 3.75" of backspace which will result in the dreaded "skateboard" look and may necessitate mudflaps to keep law enforcement at bay. In other words, 15" wheels are not an option.

My remaining options are: (1) Stay with 16", in which case I keep my existing tires and have them mounted on new wheels with a 5x5.5 lug pattern and 4.0" backspacing; or (2) Go to a 17x9 wheel with the new lug pattern and treat myself to new 35" tires.

Questions re 17x9 wheels on a TJ:

What backspacing will I need with 35x12.50 tires (or 315/70R16, the metric equivalent)? I have found a several wheels with 4.5" backspacing but most are 5" or more. A handful are 3.5. I do not want to use wheel adapters or spacers.

Phrased another way: Will 4.5" backspacing work for 35x12.50 tires mounted on 17x9 wheels used on a TJ with 4"+ lift and stock fenders?

I suspect that 4.5 backspacing will work with this combination but would like to hear it from someone with personal knowledge because five 17x9 wheels + tires isn't inexpensive.

Questions re 35x12.50R17 and 315/70R17 tires:

Most this size are D load rated, only the Goodyear MTR with Kevlar is C load rated. Let's avoid the C vs. D debate, I know it well, what I'd like to know is whether any forum members are using these two tires sizes and if so:

What are you running?
What has been a positive about your tire choice and what has been a negative?
What wheels are you using?
 
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Not exactly an apples to apples comparision...but a data point. I'm running 17 x 8.5 wheels with 4" backspacing. (JK pintlers w/ 1.25" adapters). My tires are 285/70R17. I get a bit of rub at full lock. Enough that I will either need thicker adapters or will need to adjust my steering stops. Other than full lock, I don't rub. I think you'll be too tight with a 4.5" backspace.
 
Well that is distressing news because I haven't found a 17x9 wheel with 5 x 5.5 lug pattern and anything less than 4.5" backspacing.

Do your JK Pintlers have 5.2" backspacing or are they the earlier version with 4.7" backspacing?

What would it take to persuade you to add a washer to each steering stop and test the degree of rubbing after? :)
 
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Well that is distressing news because I haven't found a 17x9 wheel with 5 x 5.5 lug pattern and anything less than 4.5" backspacing.

Do your JK Pintlers have 5.2" backspacing or are they the earlier version with 4.7" backspacing?

What would it take to persuade you to add a washer to each steering stop and test the degree of rubbing after? :)
They are the 5.2" back spacing version (+10 offset). I would love to add a washer to my steering stops for you (and for me), however, the bolts are seized in the knuckles. I have another clean set of knuckles to go on, but until I need to rebuild the front end, I just remember to back the steering wheel from full lock.
 
I'm running custom Dana 44 with manual hubs and Chevy discs on a 5x5.5 bp. The rear is a narrowed Dana 60 from a Ford 1-ton and drum brakes on a 5x5.5 bp.
When I got the Jeep, it had 15x10 chrome 8-spokes on 35" BFG's.
After a couple of wheel changes, I recently bought my Allied BL's in a 17x8, 3.75" bs, 5x5.5 bp. The tires I'm running are Copper STT Pro's, 37x12.50/17's, LR 'D'. 20psi on the street, 6-8 in the rocks. About $2300, it pays to have a separate savings account for Jeep junk.
Never really thought it looked like a skateboard, more like a top-less dumpster.
 
Update 12/19/18:

I consulted with a well known designer/builder intimately familiar with the 16" Big Brake Kit and backspacing requirements for LJ's running 35" tires on both 16" or 17" wheels. He confirmed that the same 4.0" backspacing that I have on my 16x8" wheels is still the optimum backspacing for 35's on 17x9' wheels.

Unfortunately, the 17" wheels that I like (and can afford) have backspacing of either 3.5" which is too little, or 4.5", 5.0", or greater which is too much.

However, the good news is that there are spacers available for the CJ 5x5.5 lug pattern with the 108mm center bore I need in thicknesses of 1.0", 1.25", 1.5" and 2". This means that I can choose a 17x9 wheel with 5" backspacing, use the 1" spacer and net 4" of backspacing. If in the future I determine that more backspacing is required I can swap out the 1" spacer for a 1.25" spacer and net 3.75" backspacing.

These are the suggested spacers:

100-555-555-916-3_1f623cfa-aa67-4f0c-b771-56ab887fc1e4_360x.jpg

https://www.titanwheelaccessories.c...-ram-1500-ford-f-100-bronco-jeep-cj-1-2-studs

These are the 17x9 5x5.5 4.0 B.S. wheels I have found so far in order of my likely choice:

Raceline 887 Rockcrusher
208.jpg


U.S. Wheel Daytona Series 844 Simulated Beadlock (also available in Gunmetal, Desert Sand and Black)
Daytona-Beadlock-Camo-Green_s-5001.png


Ion 171 polished aluminum (also available black)
ion-171-polished-5x5.5.jpg


U.S. Wheel 043 Crawler (steel, also available black)
Crawler-Chrome2-043_s-500_3634.png



I have always liked the look of the Rockcrushers and think they suit a TJ/LJ.

The Daytona simulated beadlocks are growing on me. This is how they look on a khaki TJ:

us-wheel-1990-Jeep-Wrangler-YJ_Series-844-Desert-Sand_7387.jpg


What do you guys think? The wheels will be on this jeep:
 
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