Novak Conversions Jeep Wrangler TJ engine mounts

I need advice on wheel width and backspacing for less common tire sizing (new tires, wheels, and lift)

Justanotherjeepguy

Justanotherjeepguy

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Original poster
Joined
Jan 15, 2020
Messages
56
Location
New Smyrna Beach, FL
The current Jeep:
• Stock 2006 Rubicon (automatic) with 31x10.5r16 tires
• 95% on the road (daily driver, but we also go on a lot of long trips throughout the states)
• 5% off-roading in mild to medium terrain, mostly to find cool views and camping spots (not looking to do extreme rock crawling or anything)


The goal:
• OME lift
• Go from 16in wheels to 15in for more/cheaper tire options
• 31x9.5r15 tires
• Classic tall and narrow overland look (FJ40s come to mind)
• Tires not sticking out past the fender flares (or at least not by much)
• Don't want to have to get a regear, so I guess I'm limited to under 31in tires?


The question:
What would be the ideal wheel width and backspacing to help me achieve this look? Will I run into any functionality issues running this tire and wheel size?


Other notes:
Many wheel options are 15x8. I'm worried about issues with this wheel size since we air down a lot (I installed an air compressor for quickly airing back up after trails). I've heard that you can have problems if your wheels are too wide for the tires, particularly without beadlocks. I don't plan to get beadlocks because they look a bit more modern or aggressive for my taste.

I know 9.5in width tires are less common on here, and I'm willing to compromise with 10.5—but I'd still prefer 9.5 for the tall and skinny look.


Thanks for taking the time to read and reply :)
- Matt
 
Last edited:
Personally Id not run a 8" wide wheel with a 9.5 tire. Plenty of guys run 33/12.50's on 8" wide wheels for sidewall protection with good success. BFG used to make a 33/9.50/15 tire. Consider unless you order custom wheels that off sets and backspacing can be generic of sorts and not really what you want. I ran stock 15x7's on my YJ with 31's and had a little rubbing on the leafs but that can be corrected. The stocker wheels were pretty ugly so I picked up some Black 15x8's from Q'tec that have 4" BS'ing. Looks cool, flings snow, mud and gravel all over the interior and its occupants. Are 15's really gonna save you much on tires from the 16's you already have?
 
Super Swampers are the only tire I know of that are 31x9.5R15, I don't think you want those. I'd just pick a 31x10.5R15 and go with stock wheels like Ravine or Canyons. They wont stick out at all with your wider flares. You'd have a few options if you keep Moabs and run 235/85R16 tires. They are about what a 32" tire is and I think a couple of people here run them, they are the tall skinny deal. With Rubicon gears you'll be fine on those but everybody has a different opinion on gears.
 
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I run 235/85R16 Duratracs on some 16X7 ZJ Alloys. Works GREAT in mountain snow commuting .
Of course load range E isn't ideal on a TJ, 26psi works for me.
These are the only "tall/narrow" tires with a useable snow tread that I have found in any wheel size.
Good luck in your quest.
 
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Vtx531 said:
So you want a 31x9.50 that stays under the flares and has no functionality issues...

Isn't that exactly how a stock Rubicon comes equipped??? Is that what you have now? 245-75-16?
Click to expand...
Stop making things easy. ;) Those metric tires aren't exactly 31" tall or 9.5" wide. Mrblaine will set you straight......or at least make you wish you were. :cool:
Rubi 6 9 (2017_11_20 00_38_12 UTC).jpg
 
Vtx531 said:
So you want a 31x9.50 that stays under the flares and has no functionality issues...

Isn't that exactly how a stock Rubicon comes equipped??? Is that what you have now? 245-75-16?
Click to expand...
It might be, but the current tires (which came on the Jeep when I bought it) are about 31.5x10.5.

When turning sharp, they rub, which is partly why I'm going to do the lift. They also stick out .5-1inch past the fender flares, but I guess that isn't a huge deal.

It looks like I'll still be running 31x10.5 since there aren't many 9.5 options.
 
Gilaguy23 said:
Personally Id not run a 8" wide wheel with a 9.5 tire. Plenty of guys run 33/12.50's on 8" wide wheels for sidewall protection with good success. BFG used to make a 33/9.50/15 tire. Consider unless you order custom wheels that off sets and backspacing can be generic of sorts and not really what you want. I ran stock 15x7's on my YJ with 31's and had a little rubbing on the leafs but that can be corrected. The stocker wheels were pretty ugly so I picked up some Black 15x8's from Q'tec that have 4" BS'ing. Looks cool, flings snow, mud and gravel all over the interior and its occupants. Are 15's really gonna save you much on tires from the 16's you already have?
Click to expand...

Thanks for the info.

I would like to get rid of the 16 Moabs—several of them are beat to hell by the previous owner, and I don't like the look enough to buy another set. I figured I should go with 15s since the tires seem easier to come by. Is there any upside to getting another set of 16s instead of 15s?

Another question:
If I were to buy 15x8 wheels and 31x10.5r15 tires (probably KO2s), would the correct backspacing be 5 inches like the stock moabs if I wanted to keep them tucked under the flares as much as possible? Or would the tire and wheel size change the amount of backspacing I need? I'm thinking about ordering custom wheels, but I'm not sure what I need.
 
Justanotherjeepguy said:
Thanks for the info.

I would like to get rid of the 16 Moabs—several of them are beat to hell by the previous owner, and I don't like the look enough to buy another set. I figured I should go with 15s since the tires seem easier to come by. Is there any upside to getting another set of 16s instead of 15s?

Another question:
If I were to buy 15x8 wheels and 31x10.5r15 tires (probably KO2s), would the correct backspacing be 5 inches like the stock moabs if I wanted to keep them tucked under the flares as much as possible? Or would the tire and wheel size change the amount of backspacing I need? I'm thinking about ordering custom wheels, but I'm not sure what I need.
Click to expand...
If you’re going for a skinnier look, why get an 8” rim instead of 7” wide? If your tires rub when turning, a lift won’t fix that.
 
deadbeat son said:
If you’re going for a skinnier look, why get an 8” rim instead of 7” wide? If your tires rub when turning, a lift won’t fix that.
Click to expand...
Good point! I'm looking at 7" now. I didn't know there were so many options for those until now. Thanks!

Oh okay, I didn't know that. I'm assuming that going to a smaller width (with the right backspacing) is the answer to tire rubbing then?
 
Justanotherjeepguy said:
Good point! I'm looking at 7" now. I didn't know there were so many options for those until now. Thanks!

Oh okay, I didn't know that. I'm assuming that going to a smaller width (with the right backspacing) is the answer to tire rubbing then?
Click to expand...
So I'm running an OME lift, 15x7 wheels with 5.5" backspacing (stock steel wheels), and 31x10.50 tires. I love the aesthetic of an old FJ40 as much as anyone (or perhaps even more so), but I'm also a fan of letting the TJ be what it is, a Jeep.

With 5.5" BS, my 10.5" wide tires would rub on the control arms at full lock when I first installed them. To remedy the situation, I simply installed a washer behind the steering stop. Here's a good thread that explains how to do this.
 
Justanotherjeepguy said:
Sorry! I meant to put that in the main post. 265/75r16 (I think it's around 31.5x10.5?) .

I'm liking ManWithJeep's suggestion (235/85r16 with 16x7s)—I didn't know they had KO2s in that size until now.
Click to expand...
For all intents and purposes, a 265/75-16 is a 32". Yes, it only measures 31.5" nominally, but so does a 32x11.50-15. The advantage to a 16" tire, in my opinion, is they are typically a little narrower than an equivalent diameter 15" tire. However, the sizes you're looking at are typically only available in a load range E, which are a little stiffer than a load range C tire. Everything has a tradeoff.
 
deadbeat son said:
For all intents and purposes, a 265/75-16 is a 32". Yes, it only measures 31.5" nominally, but so does a 32x11.50-15. The advantage to a 16" tire, in my opinion, is they are typically a little narrower than an equivalent diameter 15" tire. However, the sizes you're looking at are typically only available in a load range E, which are a little stiffer than a load range C tire. Everything has a tradeoff.
Click to expand...
Good to know! I didn't notice that sneaky "E" at first glance. I wonder if it'll be much of a difference. Time for more research...

Thanks for the info!
 

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