35X1250R15 tires on what back spacing?

[ewander]

Hi, I need some help with back spacing. I did some searching but didn't get my question answered.

What backspacing should I use for some new 15X10 inch rims for us with my 35X1250 BFG MTKMs?

Will 3.75" keep the tires out of my control arms at full turn?

 

[OT]

1.75" for the KMs.

 

[Ramsey]

i thought with those you wanted 2"?

 

[ZachMan]

Hi, I need some help with back spacing. I did some searching but didn't get my question answered.

What backspacing should I use for some new 15X10 inch rims for us with my 35X1250 BFG MTKMs?

Will 3.75" keep the tires out of my control arms at full turn?

4.25" backspacing will keep them off your arms. It all depends on how much you like your wheels sticking out. I run 4.25 because it looks perfect with no fenders.

Yeah thats with 15x8s, you don't want 10s

 

[XJ_ranger]

and you want 15x8's with thoes tires...

 

[XJSpencer]

and you want 15x8's with thoes tires...

x2 or is that 3?

run 3.75 or 4" if you want to pull u-turns anytime soon.

 

[Matt98XJ]

x2 or is that 3?

run 3.75 or 4" if you want to pull u-turns anytime soon.

I agree.

 

[Stouttrout]

Reading this post and hope this is not hijacking it, but why do you want 8" rims instead of 10" ? I am looking at the Trxus MT in a 34x12.50x16. Should I be looking at 8" rims as well? I was told once that a 12.50 might be prone to pop off an 8" more than 10" i have always run 10" just curious.

 

[Ramsey]

you've got it backwards, the 8" will hold the bead better than the 10" with a 12.50, run a 8" wheel.

 

[GottaBeJeep]

I have 35" MT/R's on 15x10's with 3.5" BS, and barely rub on the control arms, but those tires are pretty worn down, so in short, that set up still rubs the arms. I agree with the others on getting 15x8's (my 15x10's are temporary and they were dang near free), but get the least amount of backspacing you can, then get some spacers to finish pushing them out to about 1.75-2" backspacing. Gets rid of most LCA rubbing and adds awesome stability.

 

[ewander]

I have 35" MT/R's on 15x10's with 3.5" BS, and barely rub on the control arms, but those tires are pretty worn down, so in short, that set up still rubs the arms. I agree with the others on getting 15x8's (my 15x10's are temporary and they were dang near free), but get the least amount of backspacing you can, then get some spacers to finish pushing them out to about 1.75-2" backspacing. Gets rid of most LCA rubbing and adds awesome stability.

I thought I wanted to get more backspacing to avoid wheel spacers.... Besides, technically aren't wheel spacers the exact same thing as additional back spacing?

I have about 7.5" of lift with the RE Long Arm kit, so I sit a little tall. I also have bushwacker flares. I have run 8" rims for a long time, but think the 10 inchers would make me a little more wider, hense more stable in off camber situations. The lowest I take my air pressure is down to 10 lbs, so hope I would be able to keep a bead.

 

[ZachMan]

x2 or is that 3?

run 3.75 or 4" if you want to pull u-turns anytime soon.

4.25 is fine too, I can max out my steering left and right and no rubbing at all.

 

[ZachMan]

I have about 7.5" of lift with the RE Long Arm kit, so I sit a little tall. I also have bushwacker flares. I have run 8" rims for a long time, but think the 10 inchers would make me a little more wider, hense more stable in off camber situations. The lowest I take my air pressure is down to 10 lbs, so hope I would be able to keep a bead.

Sounds like you need less lift. 35s on the RE 4.5" is perfect.

 

[GottaBeJeep]

Besides, technically aren't wheel spacers the exact same thing as additional back spacing?

Yes, but most wheels don't have 2" of backspacing. I would keep your 15x8" and add a wheel spacer to push those wheels out as far as you can.

 

[BEVAN]

Sounds like you need less lift. 35s on the RE 4.5" is perfect.

:huh: You forgot to add trimming

 

[XJSpencer]

I would like to point out that only one person is recommending you push your tires WAY out. The further you push them out, the more leverage you're getting on your hubs, lugs, ball joints, etc. I personally run 35's w/3.75" BS and it turns incredibly sharp. Before and after the longarm conversion.

If you want a wider track width, go full width. Wheel spacers are illegal in most states anyway. They definitely are in Utah.

This is free info.

You get what you pay for.

I'm just trying to help.

Now get out and wheel!

 

[Tom in KY]

I stole a pic from a previous thread, posted by Yucca Man. A picture is worth a thousand words. Back spacing is measured from the back of the wheel to the mounting surface.

Jeeps come from the factory with negative offset wheels, meaning that the backspacing is greater than 1/2 of the wheel width, in the case of a stock Jeep XJ, 5 1/4". This places the center of the weight load back from the mounting surface, more toward center of the hub bearing. Wider wheels with the same backspacing change the load center outward. Less backspacing puts the load center further out from center of the bearing. This leverage adds up. Ask anyone who had a Dodge Dana 44 front axle with those horrible bearings from 74 to 78?,, I measured mine out once and did a scale drawing with 35" tires, the leverage against the bearing was nearly 10:1 at static load. No wonder they failed so often. Jeep hub bearings are a similar design. I'd avoid 10" wheels. I'd also avoid a shallow backspacing.

 

[sidriptide]

I have run 8" rims for a long time, but think the 10 inchers would make me a little more wider, hense more stable in off camber situations. The lowest I take my air pressure is down to 10 lbs, so hope I would be able to keep a bead.

a wider wheel will have a MUCH looser grip on the tire ESPECIALLY in off-camber situations... ever roll a bead of the wheel?? a 10" wheel will increase your chances of doing just that. that would be fine for a mall cruiser, but on the trail i'd rather not invite that chance.

 

[EricsXJ]

I'm running 3" BS on mine and I love it. Turns great (not as good as stock, but hey...) and the wider track sure is nice for stability like GottaBeJeep pointed out.

I'd say 3.75" would be the minimum.

 

[ZachMan]

I'm running 3" BS on mine and I love it. Turns great (not as good as stock, but hey...) and the wider track sure is nice for stability like GottaBeJeep pointed out.

I'd say 3.75" would be the minimum.

You must be running fender flares, lol. 3" backspacing with 33s with cut fenders would look like a hoopty.