What backspacing do I need for 31X10.5R15 wheels?

[TmLIsMe14]

I would like to get some new tires and wheels for my jeep wrangler. I currently have 31x10.5R15 Cooper STT Pros on what I think are stock wheels. I don't know much about my jeep because I bought it with the current tires and wheels that it currently has. What I do know is that the speedometer is off and that I have wheel spacers.

I am looking at GYW Duratracs in the 31x10.5R15 but I don't know what offset or backset I need if I even need them.

 

[ballpark]

Post a picture of your jeep.

 

[JEEPCJTJ]

A close shot of a wheel/tire would help too.

 

[Goatman]

Get one of the many GPS speedometer apps and find out how far off you really are. There are a few ways to get it reading accurately again. Pull a wheel off and measure the backspacing and width of the rim too.

 

[TmLIsMe14]

Sorry for this insanely late reply. But here are the pictures of my Jeep and my tires/wheels.

 

[Fonz54]

Those are Gambler wheels. They were an option with the 30” tire package in TJ Sport models.! Not sure why there are spacers installed.

 

[jeepins]

Thought the same thing.. Jeep wheels, why are there spacers unless that's just a visual preference? And after you figure out your tire/size pretty much all the typical Jeep parts sites will sell the speedo gears and they're easy to install.

 

[glwood]

I would like to get some new tires and wheels for my jeep wrangler. I currently have 31x10.5R15 Cooper STT Pros on what I think are stock wheels. I don't know much about my jeep because I bought it with the current tires and wheels that it currently has. What I do know is that the speedometer is off and that I have wheel spacers.

I am looking at GYW Duratracs in the 31x10.5R15 but I don't know what offset or backset I need if I even need them.

Had that exact TJ, same color & wheels, back in the day. That size tire will fit, and should without spacers. Although, you may get a bit of rubbing on the lower control arm at full steering lock with the 10.5" width. A washer or two on the steering stop will prevent rubbing.

If you are buying new wheels, a bit less backspacing will eliminate any rubbing on the LCA.

 

[TmLIsMe14]

So my wheels that I have are stock? Also, a 31x10.5R15 would fit stock on my TJ?

My next question, are there better ATs out there for snow that are comparable to the GYW Duratrac? I don't know how good my current tires are in any offroad situation nor do I know how good they will perform in the snow. I would just like a tire that would be good in the snow when it starts to snow here in eastern CT.

Also, as for the wheel spacers, I don't know much about them, they came on the Jeep along with the tires. I didn't know if my jeep needed the spaces or not. I actually didn't know about them until my mechanic told me that my TJ had them on my wheels.

I just want 31s on my Jeep, I don't plan to off-road this Jeep, this Jeep that I bought was beaten into the ground and for now, I want my Jeep to rest easy until I can get another Jeep.

 

[Creakydoor]

I have those same Gambler rims on my 97 TJ. I had 10.5” wide tires and it definitely rubbed at full lock in the front. I debated new rims, but for $$$ reasons, I got 1.5” Spidertrax wheel spacers instead. No rubbing with that setup at all.

I run BFG KO2’s, and so far they have been great in our Colorado snow.

I have 33’s now, but ran 31’s stock for years, and didn’t have issues, but that was all on road, not off road.

 

[Goatman]

I used to swear by the BF Goodrich A/T until I got a deal and switched to the Cooper AT3 LT. Huge improvement on snow and ice on the road. They are "3 peak" rated for winter tires. Come in a C range for a good ride. I have not used the NEW BF Goodrich A/T 3 to compare to.

 

[bobthetj03]

4" of back spacing would be preferable. Tough to beat the Duratracs for snow from what I've read. I run BFG KO2's. They seem to be good in wet, but haven't tried in heavy snow quite yet.

 

[T Crawford]

The gamblers wheels are also 8 inches wide if I recall

 

[Creakydoor]

Yes, that’s true according to these specs here.

https://wranglertjforum.com/threads/wrangler-tj-stock-specifications.71/

 

[OHFIVETJ]

No spacers here / Mickey 265-75-16 ATZ P3

 

[JEEPCJTJ]

I'm running Duratrac 235/85 R16 on original wheels on a stock Rubicon. They are basically 31.5" x 9.25". They were great in the snow last winter, very acceptable in the mud and I've never had them rub on any part of the Jeep.

 

[davidgoodman]

I put 31x10.5s on factory wheels and the tires rubbed the control arms.
Installed a set of Cragar V5s 10x8 with 3.75 backspacing, they do not rub now.

 

[TmLIsMe14]

I had my mechanic look at my wheels and tires, I asked him to pull off a spacer to see if the tires/wheels would fit. He told me that the studs were not long enough for the rims and that he would have to put whole new studs on to it to fit.

On another note, has anyone used the Cooper STT Pros? How good are they? I am mainly concerned about the snow, as I said in a previous post I wouldn't be offroading my Jeep since it was beaten before I got it. This is my DD and I can't afford to offroad and have my only vehicle be down on me.

I've been looking at Duratracs since they were first announced back in 13, I had a feeling that they would be amazing in the snow, but this was back in 13. It is now 2019 and I have not seen some of the tires that are available today that were in 13. If someone could recommend me a good AT that is good in snow (better if it's snowflaked) that would fit my TJ stock.

Also, this is late but, happy holidays, this past recent holiday.

Cheers.

 

[TmLIsMe14]

Also, how do I find out what kind of axle I have for the rear? I have a 1998 TJ 4.0 Sport with a 3.73 ratio. I am unsure of what I have. Do I have a limited-slip differential? I bought this jeep as it is and I don't know anything about it. What I do know is that the previous owner beat this Jeep and I had to get a full rear differential rebuild from my mechanic.

From what I was told, my teeth in the differential were broken, I think. I know he said that there were metal shavings in the differential. I think my mechanic said the control arms were ripped off, so he had to rebuild that as well. As well as the shocks not being bolted tight at all. According to my mechanic, he had to retighten every bolt.

The person who I bought my Jeep from said that my Jeep originally came from Vermont, that's all I know about the previous history about my Jeep.

Oh, and my mechanic said that the previous owner or someone put a different differential plate on my rear axle so to find the ratio of my axle he had to tape a tire and the driveshaft and spin it and count the rotations I guess.

 

[JMT]

I had my mechanic look at my wheels and tires, I asked him to pull off a spacer to see if the tires/wheels would fit. He told me that the studs were not long enough for the rims and that he would have to put whole new studs on to it to fit.

On another note, has anyone used the Cooper STT Pros? How good are they? I am mainly concerned about the snow, as I said in a previous post I wouldn't be offroading my Jeep since it was beaten before I got it. This is my DD and I can't afford to offroad and have my only vehicle be down on me.

I've been looking at Duratracs since they were first announced back in 13, I had a feeling that they would be amazing in the snow, but this was back in 13. It is now 2019 and I have not seen some of the tires that are available today that were in 13. If someone could recommend me a good AT that is good in snow (better if it's snowflaked) that would fit my TJ stock.

Also, this is late but, happy holidays, this past recent holiday.

Cheers.

Your wheel studs should be long enough. The mechanic who told you that is giving you BS.
Your Jeep is not a fragile toy. Regardless of its past, unless it’s a rust bucket, it should be fine to off-road.

Duratrac
KO2
Cooper AT

the Cooper STT Pro are a semi MT tire. Great for rocks and mud, but not well known for snow.