smtippin

Stock rims cause LCA rub at full lock. What backspacing on 15x8s do I need for 31x10.5 or 32x12.5 tires to avoid rubbing at minimum? Also, what backspacing causes tires to stick out 'the right amount'. Previous thread search suggests 3.5-4". Does that sound right?

Thanks,
s

Donnie_K

I run 4 inches on mine and don't rub at all. 4" on a 8 inch wide rim also means 0 offset. The rim meets the drum or disk right in the center of the rim.

Brad M.

For a 31-32" tire you should be fine with 4" to 4.25" BS. I run 15x8 wheels with 4" backspacing on 33x12.50's and don't rub the LCA's at all.

mitchell205

you will be fine with 15x8 4 inch back spacing these are most common and there cheap I just got a set of four for $50 check my build thread link below

96liftedXJ

Im getting ready to buy 4.75 backspaced soft 8's for my 33x12.5's. But right now with a 3in lift with 31's im running 4.25 bs with no problems. But with the 33's on stock wheels the rub a little but not much.

smtippin

Is that good? Does offset matter?

s

smtippin

You do know that the higher the number, the closer IN the tire sits right? A 3.5" backspace will in fact stick out more than a 4.5".

s

96liftedXJ

Really? Everyone that i have talked to has said the opppsite. I was thinkin what you said and then everyone was like no no. So i guess its a good thing that i havent ordered them yet. So tell me this, Do i measure from the outside of the wheel to the mounting surface or from the inside to the mounting surface? Cuz i was told to measure from the outside to mounting surface to get the backspace. Cuz on the wheels that im running now i did that and it measures 4.25 or 4.5. So please let me know before i order the wheels. I want my 33's to stick out there! Father than my 31's do. So since the wheels are goin to be for a 33x12.5 on a 3in lift what backspace will put them out there far? or what would you run smtippin?

builtnotbought89'

I'm not really sure about the mix up, but i think that 4" BS is better than 4.5" BS, cause I'm running 3.75" BS with 31x11.5's -

smtippin

Go here: www.rsracing.com/tech-wheel.html or here http://www.fourwheeler.com/techartic...tte/index.html

Most of what I hear on this forum is that 3.75 or so of backspacing is good. I'd search the forum for backspacing for more info specific to your question. Check out builtnotbought89's photo. That is a great way to base your decision from.

s

EzLivn

I just put 33X10.50s on 15X8" rims with 4 3/4 bs.They don't rub and stick out a little beyond the flare.If I had it to do over I would probably go with 4 1/4 bs.

96liftedXJ

Ok, i got it. I think ill go with the 4in bs. Ill measure my wheels that my 31's are on and see what they are before i order anything. So Thanks for the info. Im glad i didnt order them and then get pissed when i found this out. Thanks guys.

Donnie_K

you guys gotta understand what backspacing really is. the lower the backspacing, the further away from your control arms your tire will be... the higher the backspacing the closer they will be to your control arms. stock rims are like 5.25" of backspacing. That's why 31's will rub the lower control arms on stock rims. 4" inches is definately a good choice. no more than 4.5 inches. Also the further your tires stick out, the harder it is on your wheel bearings. I just like the idea that 4" of backspacing on a 8 inch wide rim keeps the mating surface centered on the rim. Seems better balanced to me, but I could be wrong.

caged

i have 2 tj's with 33x12.5 on 15x8 steelies with 3.75 backspacing, and they still rub at full turn against the stock lower control arms.

as mentioned, 3.75 sticks out nice, 4.5 will keep them tucked under the fenders a little, but will rub more than the 3.75.

yes, measure from the back of the mounting surface to the rear edge of the rim for backspacing. don't worry about offset.

96liftedXJ

Ok. I agree with Donnie K about the idea if keeping it in the middle of the wheel. I would like to go 3.75 but they dont offer soft 8's in that. Im going to get the 15x8's with the 4in bs. I think that it will look good with the 33's. The only way ill know is to do it. So ill let you guys know what it looks like, Ill post some pics when i get them done.