Need some education on offset and backspacing...I'm so confused....

Captain Skip

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I want to upgrade my wheels and tires on my 2020 JL Sport S. I've got the tire part figured out, I'm going with Toyo Open Country ATIII in 285/70/17. My problem now is trying to figure out what I can do for wheels. I don't know anything about wheels. I do know that I really don't want the tires extending out past the fenders, I'm trying to avoid road rash on the sides of the JL from the tires throwing up rocks and sand. I understand the stock OEM wheels are 0 offset and are 7" wide. That much I understand, but then there's + and - offset for aftermarket wheels and to further complicate things there's backspace...whatever that is. As I said, I want to try to keep the tires under the fenders but I don't want to limit my steering's ability to turn. I'm not sure I want or need 9" wide wheels for 285/70 tires so I think it makes sense to stay with an 8" or 8.5" wheel. I'm leaning towards the Method 316 in Titanium which is 8.5" wide, the Pro Comp 1069 which is 9" wide or Vision 351 Flow which is available in 8" wide. Thoughts, comments, suggestions? Thanks





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I want to upgrade my wheels and tires on my 2020 JL Sport S. I've got the tire part figured out, I'm going with Toyo Open Country ATIII in 285/70/17. My problem now is trying to figure out what I can do for wheels. I don't know anything about wheels. I do know that I really don't want the tires extending out past the fenders, I'm trying to avoid road rash on the sides of the JL from the tires throwing up rocks and sand. I understand the stock OEM wheels are 0 offset and are 7" wide. That much I understand, but then there's + and - offset for aftermarket wheels and to further complicate things there's backspace...whatever that is. As I said, I want to try to keep the tires under the fenders but I don't want to limit my steering's ability to turn. I'm not sure I want or need 9" wide wheels for 285/70 tires so I think it makes sense to stay with an 8" or 8.5" wheel. I'm leaning towards the Method 316 in Titanium which is 8.5" wide, the Pro Comp 1069 which is 9" wide or Vision 351 Flow which is available in 8" wide. Thoughts, comments, suggestions? Thanks
As far as I know, all factory wheels are 7.5" wide and have a +44.45mm offset.

Offset refers to where the mounting surface of the wheel is in relation to the width of the wheel. Dead center is 0. As the mounting surface moves towards the outer face of the wheel, the offset number increases on the positive side. As it moves towards the inside, the negative offset increases.

Backspace is the distance from the mounting point to the inside bead of the wheel. This one is generally measured in inches. That would put the factory wheel at about 5.5" of backspace.

The Rubicon, which also has a 7.5" wheel, comes from the factory with 285/70-17 tires. An 8" wide wheel should be plenty for those 285's, could also support the possibility of bumping up to a set of 315's in the future, and will help minimize the wheels physical weight.

Check out the website tiresize.com and play with the offset calculator. It gives a great visual comparison and various measurement changes between what you currently have and are wanting to do.
 

Renegade

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Positive offset moves the wheel inside the fender well from 0. A wheel with negative offset moves it outboard from 0. The post above is correct about factory offset being +44. If you want the tire inside the fenders, look for something around +25.
 

AnnDee4444

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OP: Play with this calculator to get a good feel of how everything relates https://tiresize.com/wheel-offset-calculator/

To keep the tires under the fenders, I would aim for the offset to be between stock and +25mm.

As far as I know, all factory wheels are 7.5" wide and have a +44.45mm offset.
There's two stupid exceptions:
- High Altitude is 8.0" wide... don't know the offset
- Mojave is +37mm offset


I always wondered if it would be possible to run a WK2 wheel with a 1.25" spacer, for a cheap OEM quality upgrade. There are three different 17"x8" WK2 wheels, all with 56.4mm offset. A 1.25" spacer would give it a 24.65mm offset.
 

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OP: Play with this calculator to get a good feel of how everything relates https://tiresize.com/wheel-offset-calculator/

To keep the tires under the fenders, I would aim for the offset to be between stock and +25mm.


There's two stupid exceptions:
- High Altitude is 8.0" wide... don't know the offset
- Mojave is +37mm offset


I always wondered if it would be possible to run a WK2 wheel with a 1.25" spacer, for a cheap OEM quality upgrade. There are three different 17"x8" WK2 wheels, all with 56.4mm offset. A 1.25" spacer would give it a 24.65mm offset.
Just to clarify, the High Altitude is the Sahara with 20's and body colored bumpers and mirrors? And only the JT has a Mojave version?

I don't really follow all of the various editions, so I have to start asking what specific version they have before putting false info out there for the next person to read.

Thanks for straightening that out!
 

AnnDee4444

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Just to clarify, the High Altitude is the Sahara with 20's and body colored bumpers and mirrors? And only the JT has a Mojave version?

I don't really follow all of the various editions, so I have to start asking what specific version they have before putting false info out there for the next person to read.

Thanks for straightening that out!
Yeah, you got it correct. There have been rumors of a JL Mojave, but nothing official.

Oh and the 392 is supposed to have "Beadlock Capable" wheels. I haven't been able to find any specs on them yet, other than they are 17" in diameter.
 

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