Another Backspacing Thread

U8MYDZT

U8MYDZT

Wrong guy to follow
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I have been doing a lot of work under the Jeep with all this extra time and while checking my bump stops I noticed the front tires rub pretty hard on the shock towers under full stuff and the wheels turned. I have been looking everywhere and all the information I can find says my wheel/tire combo should be just right. I have the Mammoth D Window 15x8 with a 3.75" backspacing and 33x12.5 DC tires, does this setup usually require wheel spacers added to get clearance?
 
I have 35x12.3 effective tires on 16x8 rims with 3.75” net backspacing. I will get a small amount of rubbing at full flex and wheels locked.

Can you confirm the backspacing on the wheels by measuring? I see there’s several different backspacing options available in that size and style wheel.

Is it only occurring at full lock or is it occurring at less severe steering angles?

If it’s at or near full lock you can simply add a washer or two to your steering stops to reduce the overall steering travel. (If it’s not severe rubbing, you might even be able to just let it go if you rarely flex that far)
 
Steel City 06 said:
I have 35x12.3 effective tires on 16x8 rims with 3.75” net backspacing. I will get a small amount of rubbing at full flex and wheels locked.

Can you confirm the backspacing on the wheels by measuring? I see there’s several different backspacing options available in that size and style wheel.

Is it only occurring at full lock or is it occurring at less severe steering angles?

If it’s at or near full lock you can simply add a washer or two to your steering stops to reduce the overall steering travel. (If it’s not severe rubbing, you might even be able to just let it go if you rarely flex that far)
Click to expand...
Its WAY before full lock. I will check the actual offset, but the only offset I see on extreme terrain for these wheels is 3.75".
 
U8MYDZT said:
Im hoping a little bit of wheel spacer will keep from extending the bumps. I would hate to loose articulation.
Click to expand...

I hear you on that. Your backspacing though is right where it should be, but obviously every case is different.
 
U8MYDZT said:
Its WAY before full lock. I will check the actual offset, but the only offset I see on extreme terrain for these wheels is 3.75".
Click to expand...
This one lists 4.5":
https://www.extremeterrain.com/mammoth-d-window-wheel-yj-tj-j100950.html
This one lists 3.75":
https://www.extremeterrain.com/mammoth-d-window-wheel-yj-tj-j102796.html
This is how you measure:
Measuring-Wheel-Backspacing.jpg
 
Last edited:
Steel City 06 said:
This one lists 4.5":
https://www.extremeterrain.com/mammoth-d-window-wheel-yj-tj-j100950.html
This one lists 3.75":
https://www.extremeterrain.com/mammoth-d-window-wheel-yj-tj-j102796.html
This is how you measure:
View attachment 149406
Click to expand...
Well SOB, I looked at them all and didn't see that offset... Good find! I will pull the wheels in a couple days when I get my wheel spacers and then measure the actual backspace. From what I can tell with them on the Jeep is they're closer to the 4.5" measurements
 
Here's a question that's sort of on topic:

Since most spacers are aluminum, albeit anodized, is there much of a problem with galvanic corrosion between the spacer and rotor? Is smearing the bearing surface with anti-seize a good idea, or can it fling out and get on your braking surfaces?
 
Unless you're using stainless rotors, galvanic corrosion is generally not a big concern. Ordinary steel or iron and raw aluminum are actually very close on the galvanic series and don't generally create significant galvanic corrosion. Stainless steel and chrome will greatly accelerate corrosion on coupled steel or aluminum.

In addition, many higher quality spacers are anodized for extra corrosion protection.
 
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