Backspacing on spare tire to properly fit spare carrier?

DaveC

DaveC

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Jan 3, 2019
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Gilbert, Arizona
Looking for help getting my spare to properly fit on my tailgate. I currently run 31/10.5 r15 Kelly Edge ATs and have a matching spare. I have aftermarket rims the PO installed when he purchased the Jeep new in 2006, but the spare is a factory steel wheel. Looking at the specs in this tread (https://wranglertjforum.com/threads/wrangler-tj-stock-specifications.71/#post-183), the backspacing and offset on my spare rim are 5.5" and + 38 mm respectively (the second wheel down with 'Unknown' as the name). I'm still searching for the specs on the rims the PO installed and haven't found them in order to compare yet.
The challenge I'm having with the spare fitting on the tailgate is the opposite of what I've found here on the forum. I don't need to extend the snubbers; I've actually had to grind down the bottom snubber to prevent it from pushing the bottom of the tire out and torquing the tailgate outward when closed. This causes the need for a lot of force to fully close the tailgate and then it pops out when opening (not the smooth open/close it had before putting the larger spare on - it came with the tiny original spare). Essentially, the added outward tension on the lower portion of the tailgate causes the latch to be out of proper alignment and therefore, bind.

Also, the spare gets maybe 3/4" of bite on the lugs on the carrier. I've got it firm and secure, but I occasionally have to make minor adjustments to the lugs on the carrier to keep the tailgate from binding when opening and closing (loosen this lug, tighten that one, etc.). It's an ongoing balancing act and it seems that I should be able to get more bite on the lugs and not have to constantly adjust to avoid the binding issue. I'm wondering if the backspacing and/or offset on the current spare rim needs to be different in order for it to properly fit on the tailgate.

I know the Rubicons came stock with 30.5x9.6 r16 tires and the spares fit properly on the tailgate, and I see that the backspacing and offset on the Moab wheels are 5" and +12 mm. So my question is, would finding a wheel that has a closer offset and/or backspacing to the Moabs that came stock on the Rubicon make the difference in the spare properly fitting on the tailgate?
 
If you need to push the rim out a bit you could add a wheel spacer to achieve that. Are you sure your tail gate hinges don't need to be adjusted?

Photos may help.
 
We have a bazillion used tire dealers in ABQ. Were I in your shoes, I'd go to one of those, if you know of some, and see if they have a 15" wheel with less backspacing that would accomplish what you want.
 
Alex01 said:
If you need to push the rim out a bit you could add a wheel spacer to achieve that. Are you sure your tail gate hinges don't need to be adjusted?

Photos may help.
Click to expand...
Yes, a spacer would accomplish that, but then I'd have even less of the studs for the lugs to bite. I'm at less than an inch now and don't feel good about trying to hold that spare on with the lugs grabbing even less of the studs. I actually did stack washers behind the wheel to figure out how much of the snubber to shave off and with the tire far out enough/properly fit to where the door doesn't bind, the studs barely stuck through the rim enough for the lugs to bite. I measured the depth of the stacked washers and cut that much off the bottom snubber to get where I am now, but am at the point where If I shave any more off that snubber, the tire won't make contact.
 
glwood said:
We have a bazillion used tire dealers in ABQ. Were I in your shoes, I'd go to one of those, if you know of some, and see if they have a 15" wheel with less backspacing that would accomplish what you want.
Click to expand...
Same here and that was my train of thought. Still learning, so wanted to make sure my assumption on backspacing and/or offset being the culprit was accurate before pulling the trigger. So it sounds like the backspacing is it and not the offset, would that be right? Or does offset come into play?

And, if it is solely the backspacing, would 1/2" make that much difference?
 
DaveC said:
Yes, a spacer would accomplish that, but then I'd have even less of the studs for the lugs to bite. I'm at less than an inch now and don't feel good about trying to hold that spare on with the lugs grabbing even less of the studs. I actually did stack washers behind the wheel to figure out how much of the snubber to shave off and with the tire far out enough/properly fit to where the door doesn't bind, the studs barely stuck through the rim enough for the lugs to bite. I measured the depth of the stacked washers and cut that much off the bottom snubber to get where I am now, but am at the point where If I shave any more off that snubber, the tire won't make contact.
Click to expand...
My thought was something like this.
20190523_141613.jpg

It would push the tire out and give you new longer studs to attach the tire to.
 
DaveC said:
Same here and that was my train of thought. Still learning, so wanted to make sure my assumption on backspacing and/or offset being the culprit was accurate before pulling the trigger. So it sounds like the backspacing is it and not the offset, would that be right? Or does offset come into play?

And, if it is solely the backspacing, would 1/2" make that much difference?
Click to expand...
When it comes to tires fitting or not, the only thing needing to be concerned about is backspacing. And yes, a wheel with 1/2" less backspacing will push your spare out 1/2" further, and give you back the ability to use more of the wheel studs.
 
glwood said:
When it comes to tires fitting or not, the only thing needing to be concerned about is backspacing. And yes, a wheel with 1/2" less backspacing will push your spare out 1/2" further, and give you back the ability to use more of the wheel studs.
Click to expand...
Got it; much appreciated!
 
The width of the tire should effect the amount of snubber needed to make propper contact dosen't it?
 
Goatman said:
The width of the tire should effect the amount of snubber needed to make propper contact dosen't it?
Click to expand...
I'm sure that comes into play. The tires that came stock on the Rubicons were 9.6" wide vs. the 10.5 mine are, so that inch of extra width, in addition to the 1/2" difference in backspacing between the Moab wheel and the one on my spare are causing the problem.

Seems like the best fix will be to find the right sized spacer (with lugs) that, when on the carrier behind the tire, will push the tire out that extra 1-1.5" while giving me enough length on the lugs to properly secure the tire.
 
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