Ideal offset/backspacing JL

DeVoTee

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Yea you're right. Hmmm Maybe my back space is not what I thought. I didn't order them. Dealer had them on there when on the lot. They show online as 5.2" but maybe they can be ordered with other backspace as well.
I think you are correct about your backspace.

What I was trying to convey is there is even more room on a Rubicon because of the wider axles. I have a JK w/ Dynatrac HD60 and I'm able to run 5.5" backspace on an 8.5" rim with 13.5" wide tires and keep the turning radius basically stock. It also improves my scrub radius over other rigs that are having to run 3.5" backspace.

The new axles on the Rubicon JL simulate what Dynatrac did with the HD 60 axle. At SEMA AEV introduced new wheels with increased backspace to (I believe) 5.8 because of the new JL design.

I prefer as much offset/backspace as I can get without bind and rubbing. Better for turning, steering (running straight/scrub radius), bearing stress/wear. Handles and feels more like stock Jeep.





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ocrejects

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I think you are correct about your backspace.

What I was trying to convey is there is even more room on a Rubicon because of the wider axles. I have a JK w/ Dynatrac HD60 and I'm able to run 5.5" backspace on an 8.5" rim with 13.5" wide tires and keep the turning radius basically stock. It also improves my scrub radius over other rigs that are having to run 3.5" backspace.

The new axles on the Rubicon JL simulate what Dynatrac did with the HD 60 axle. At SEMA AEV introduced new wheels with increased backspace to (I believe) 5.8 because of the new JL design.

I prefer as much offset/backspace as I can get without bind and rubbing. Better for turning, steering (running straight/scrub radius), bearing stress/wear. Handles and feels more like stock Jeep.
So would it be better to go with a -15 or -38?
17x9, 12.50, 5x5, -15 or -33, 71.8 hub....
 

DeVoTee

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I can't tell you which option is better, other than play with the wheel calculators!

Just know the more - Negative the less the center of the wheel supports the weight of the vehicle.

I try to stay as close to 0 or + positive on backspace as the suspension components allow.

Maybe you have a local shop that can trial fit some options, so you can see firsthand
 

zoepup

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Thanks for all the good info! There are so many variable to consider. Got a Rubi coming in soon and putting some Nitto 35x12.5's on it.

I was going to go with 20x10 wheels with -18 offset(ok shoot me for the 20) and they are on back order for 20 days. The other option is 20x9 with +1 offset. Are there pros/cons to either one?

Many thanks!
 

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I'd go w/ the +1 offset that 3/4" might not seem like much, but IMO will be a better fit.
 

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I'd go w/ the +1 offset that 3/4" might not seem like much, but IMO will be a better fit.
Thanks. Some reason missed the alert to this thread

+1 should still extend past fender, correct?
 

blnewt

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Thanks. Some reason missed the alert to this thread

+1 should still extend past fender, correct?
You listed two widths, that 20x9 +1 would be significantly closer to the fender than that 20x10 -18. The offset alone would be 3/4" inward w/ the 9" width and another 1/2" inward for the narrower wheel at the fender. So of the two wheels the 9" width would be about 1.25" inward from that 10" wheel.

As far as how much that 9" will extend out, I only have my current setup to go by, I'm running 8.5 +10 on 295 width tires, so a 9" +1offset would be about 3/4" further out from mine (if you run a similar width tire).
Since you're getting a rubicon you'll be out even further as the axles are wider.
https://www.jlwranglerforums.com/forum/threads/ideal-offset-backspacing-jl.4270/page-8#post-538233
 

jeepauug

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One thing I noticed...............
Rubicon Axles are 1.5" wider than Sport or Sahara. So it looks like to me 4.5 backspace is about right for a Rubicon and 5.2 or 3/4" more is about right for the Sport and Sahara. My wheels are 5.2 or +12 offset.

You can see Jimbox's Rubicon and my Sport have about the same amount of tire sticking out.


IMG_4901.jpg
Which wheels are these?
 

zoepup

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You listed two widths, that 20x9 +1 would be significantly closer to the fender than that 20x10 -18. The offset alone would be 3/4" inward w/ the 9" width and another 1/2" inward for the narrower wheel at the fender. So of the two wheels the 9" width would be about 1.25" inward from that 10" wheel.

As far as how much that 9" will extend out, I only have my current setup to go by, I'm running 8.5 +10 on 295 width tires, so a 9" +1offset would be about 3/4" further out from mine (if you run a similar width tire).
Since you're getting a rubicon you'll b out even further as the axles are wider.
https://www.jlwranglerforums.com/forum/threads/ideal-offset-backspacing-jl.4270/page-8#post-538233
Thanks for taking the time to explain Brad. I have run these through calculators and read everything I can on these forums. It is still a good deal of money to spend without confirmation. So thank you.

I was set on 10" wheels with 35x12.5 tires. I knew that would stick out about 2-3 inches on a Rubi. When the 10" were on back order, I was hoping a 9" would bring it in slightly with a +1. I dont' want them sticking out to far more than 2".

Now.. I am finding almost every car wash place around here wont handle thos 12.5" tires. I will admit I have not been to an auto car wash since 1986. However, even many of the hand ones around here still run the car down a track.
 

ocrejects

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Thanks for taking the time to explain Brad. I have run these through calculators and read everything I can on these forums. It is still a good deal of money to spend without confirmation. So thank you.

I was set on 10" wheels with 35x12.5 tires. I knew that would stick out about 2-3 inches on a Rubi. When the 10" were on back order, I was hoping a 9" would bring it in slightly with a +1. I dont' want them sticking out to far more than 2".

Now.. I am finding almost every car wash place around here wont handle thos 12.5" tires. I will admit I have not been to an auto car wash since 1986. However, even many of the hand ones around here still run the car down a track.
Don’t run it through the car wash, have them wash it by hand like you would at home.
 

JohnJG

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Found a nice video by Ryan over at XT. He tests 35s and 37s on a stock Rubi and Sport using 17x9 4.5bs. Helps to visualize it all.

 

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So i just purchsed some XD wheels 17x8.5 4.75 BS. Gonna put 315/70R17s on - can some one help me out on how much poke there will be? My other option is a 17x9 5.71 BS -

I'm running a 2" lift with 1.75" spaces on stock wheels...
 

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Looks like that would be a 0 offset, here's my fit on a 8.5 +10 on 295s, your would be 10mm out for offset and 10 mm out for wider tire, so a net 20mm out from mine. That other option has too much backspacing, your current spacer would be too thick, but something like a 3/4" spacer would work.

100_4025.JPG


100_4027.JPG
 

jeepauug

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Thanks. I’m ditching the spacer. I ordered the 0 offset which seems like it’s reasonable (I think). Part of the reason for jumping is to eliminate the spacers.
 

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