Help with some wheel dimensions please?

J

Jeff Allan

TJ Enthusiast
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Nov 6, 2015
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I have stock moabs 16x8 and they have 5" BS. The wheels I was wanting were 17x9 with 4.5" BS. Comparing similar sized tires, how much would the 2nd example move the tire/wheel outwards? I was thinking 1" (.5" less BS, + half of the wheel's increased diameter) further out. So 1" but a DT rep who is knowledgeable on this, told me it'd be 1.5". ... which is going to be too much for me.

.. so I kinda gave up on the idea but then found this a program and unless I'm mixing something up, it says a 265/75/16 to a 265/70/17 with those wheel specs will move them out .9" That'd be perfect, if that's what it really is.

http://www.rimsntires.com/specspro.jsp
 
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1.5"

You moved the mounting surface .5" in plus you added 1" to the width. The joy of backspace.. simple to calculate.

Put another way. your original rim had 3" to the outside.. 8" - 5.0" BS.
The new one has 4.5" to the outside. 9" - 4.5" BS
 
I knew about the .5" movement of the mounting surface, but I figured since the rim was 1" wider it would be divided in half and then you'd have another .5" that the tire would move out since the other .5" from the increased tire width would be added to the inside of the wheel (not the outside).

Clearly my calculations were wrong.
 
Your second senario? Not following. Regardless of the tires the same rims will shift the outside bead 1.5".
Maybe look at a 17x8 rim with a 4.25" backspace. 8" - 4.25" BS = 3.75" to the outside.. vs your current 3.0".
And 17x8 with 4.25BS is pretty common.
 
Here are 33x10.00x17s on 17x8 with 4.25BS... under 6" flares.
Those are the skinniest tires I could find.. BFG MT2s 255/80R17

AEV .jpg
 
Those line up just perfect if you ask me!

I'm going to have issues with my 7" fender flares and the stock Moab wheels with 285/75r16 tires. They're not going to stick out far enough. I'm going to need a new wheel with different backspacing.
 
billiebob said:
1.5"

You moved the mounting surface .5" in plus you added 1" to the width. The joy of backspace.. simple to calculate.

Put another way. your original rim had 3" to the outside.. 8" - 5.0" BS.
The new one has 4.5" to the outside. 9" - 4.5" BS
Click to expand...

That second description makes it easy to understand….but Why does that program show 1" difference like I originally thought? When I put the sizes in. When I change the offsets it changes how much the wheel sticks out, tho' the rim stays the same size. So confusing.

I find I need to put the offset of the moab rim to get 5" BS and then that tells me the new wheel will stick out 1".
 
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This is what I'm shooting for. I wouldn't mind a bit less than this, but not any more than in this pic. I'm worried 1.5" will be too much for this look. any comments?
2011-01-17144135.jpg
 
You're going to be finding mud and rocks everywhere, let me tell you that.

Ask me how I know (my wheels stick out just about that far right now).
 
always loved that look. Here's another shot, just from a random search. Guy said it was 31's, but it looks so good. I love this look more than the lifted kinda giant wheel type.
2011-01-17144641.jpg
 
and he's rockin' the Duras Chris.. It looks like he's out exactly the length of one of those big lugs.
 
Haha, maybe you need a yellow Jeep!

My tires stick out identical to that last photo there. I would say my tires are out about 1-1.5" past the fenders (and the Rubicon has wider fenders than base model TJs from the factory).

Of course I am running 33" tires though so that has something to do with it.
 
Post a pic of it, love to see it because mostly all I can find is JK's when I start searching for BS and that type of thing. JK's have much bigger plastic and I can't tell what it'd look like on a TJ.
 
Jeff Allan said:
always loved that look. Here's another shot, just from a random search. Guy said it was 31's, but it looks so good. I love this look more than the lifted kinda giant wheel type.
View attachment 861
Click to expand...
What you need to find out is..

Wheel/Rim size and Backspace
And flare width
Maybe tire size

My guess is about the same rims I have but much narrower flares.

Chris, What are the stock TJ flare widths. I think the SE, Sport and Rubicon are all different.
 
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billiebob said:
What you need to find out is..

Wheel/Rim size and Backspace
And flare width
Maybe tire size

My guess is about the same rims I have but much narrower flares.

Chris, What are the stock TJ flare widths. I think the SE, Sport and Rubicon are all different.
Click to expand...

3.25" - used on all SE, X
4.25" - used on all Sahara, Rubicon, and Special Edition models that have painted or body colored flares
 
Looks awesome, Chris. I like that look a lot. Your rubi looks killer. Tell me more about that supercharger. What does something like that cost.and how much do you gain in power.
 
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