1/4” wheel spacer on Mojave.

[Renegade]

Offset is useless is you don’t know wheel width period.
and on jeeps the outside edge is rarely the issue since you don’t tuck a Jeep like you do a car.

We disagree.

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[JT1]

We disagree.

Explain why
On a Jeep all the lift vendors deal with backspace. The outside edge of the tire is way less important than the inside edge..

 

[Planerdude]

We disagree.

So this is what these calculators are telling me. I used a 37” diameter tire in the new wheel set up, for visual purposes only. Let me know what you think.

 

[Renegade]

Explain why
On a Jeep all the lift vendors deal with backspace. The outside edge of the tire is way less important than the inside edge..

Offset identifies not only where the centerline of the wheel is, but also where the tire contact patch is. Offset is constant, where as the tire contact patch location varies with backspacing based on wheel width. To me, offset is a more consistent way to identify tire placement within the wheel well. My disclaimer is that it should only be used with a reasonable width wheel for the application.

 

[JT1]

So this is what these calculators are telling me. I used a 37” diameter tire in the new wheel set up, for visual purposes only. Let me know what you think.

The 8.5 inch wheel you are looking at will be fine on your setup, the 37 might rub the LCA at full lock, but that’s an easy fix

 

[Renegade]

So this is what these calculators are telling me. I used a 37” diameter tire in the new wheel set up, for visual purposes only. Let me know what you think.

Yes, that appears accurate. I just don’t like those style spacers in most cases.

 

[Planerdude]

Explain why
On a Jeep all the lift vendors deal with backspace. The outside edge of the tire is way less important than the inside edge..

Agree the inside edge, of the tire, not the wheel is the critical number. As the tire is wider than wheel.

 

[Planerdude]

Yes, that appears accurate. I just don’t like those style spacers in most cases.

I prefer no spacers ever.

 

[Planerdude]

Offset identifies not only where the centerline of the wheel is, but also where the tire contact patch is. Offset is constant, where as the tire contact patch location varies with backspacing based on wheel width. To me, offset it a more consistent way to identify tire placement within the wheel well. My disclaimer is that it should only be used with a reasonable width wheel for the application.

Totally agree

 

[JT1]

So this is what these calculators are telling me. I used a 37” diameter tire in the new wheel set up, for visual purposes only. Let me know what you think.

That calculator does not take wheel width into consideration. The 9.5" wheel is 1.25" closer to your lower shock mount and swaybar links. It will rub. The 8.5" wheel is good to go.

 

[Planerdude]

That calculator does not take wheel width into consideration. The 9.5" wheel is 1.25" closer to your lower shock mount and swaybar links. It will rub. The 8.5" wheel is good to go.

But how much closer is the tire. As the tire is always centered over the wheel, given the same tire width, the same offset, different wheel width would not change tire distance to suspension parts.

 

[Renegade]

But how much closer is the tire. As the tire is always centered over the wheel, given the same tire width, the same offset, different wheel width would not change tire distance to suspension parts.

Tire section width will increase some with wheel width. About 1/4” on each side for every inch of overall wheel width increase.

 

[JT1]

But how much closer is the tire. As the tire is always centered over the wheel, given the same tire width, the same offset, different wheel width would not change tire distance to suspension parts.

Yes it does. Thats the piece with offset that the calculator you used doesn't take into consideration.

Offset is a measurement that doesn't take width into consideration. a 0 offset on a 7" wheel is a 3.5" backspace. a 0 offset on a 10" wheel is a 5" backspace.
You can run a 35x12.50 r17 stock on a Rubicon. A Mojave is fine on a 35x12.50 on stock wheels because of the lesser backspace. A 37 will probably rub on the lower control arm. To fix that issue, you need to move the inside edge of the tire and wheel outboard. The shock body on the Mojave is what prompted the wheel change to it. A Stock 7.5 +44 got too close

 

[Levi.Butler]

Why is this always so hard for people to wrap their heads around?

Same offset + different width = different backspacing
Same backspacing + different widths = different offset

This is why backspacing is SOOOOOO much easier to deal with when you are working on a Jeep. A 15" wide wheel with 3" of backspacing is going to be the exact same distance from your suspension components/frame as a 4" wide wheel with 3" of backspacing. If you've got a bigger tire with more bulge in the sidewall then get something with LESS backspacing.

GENERALLY SPEAKING... the inside of the wheel is the important part on a Jeep. Sure, if your setup is too wide with too little backspacing, and you actually wheel your Jeep, then you can have issues getting into your fenders when you are flexed out.

Keep it simple. Life's easier that way. I feel like the debate about how to make these measurements comes up way too often and it's always someone trying to flex their muscles about how smart they are since they can do simple math. Doing it all based off of offset calculations is like a young engineer that's never gotten his hands dirty but wants to prove his concept with math vs the backspacing route being an old callus-handed farmer just knowing what works. HAHA!

 

[jeepin48]

Only downside to 1/4" spacers is you probably wont find any that are hub centric (center ring"

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