JBA High Caster UCAs Wheel Clearance

I will be installing a pair of High Caster JBA uppers next weekend along with my new suspension from Bilstein. I know you have to have a certain amount of backspacing to not rub on the UCA. I currently have 17x8.5 0 offset 4.75in bs. I will be running Ridge Grapplers C load 285/70s. Based on JBAs website I should be fine but Nittos do run a tad on the wide side compared to others.
Anyone running these UCAs with similar backspacing and 285s? Any rubbing?

 

I’m running the same only 285/75-17. I rub when in reverse full lock. Ordered 1” spacers.

 

Same wheel size exactly with JBAs? I may need new wheels cause I refuse to use a spacer.

 

Yep exact same wheel specs.

 

running a similar set up except 4.30 BS with stock UCAs. I have 2" of lift. I rub ever so slightly both front and back on plastic at full lock when hitting it hard (like a curb or pothole). Without question if I had more caster from UCAs that it would rub on the back on the cab mount. Probably would clear the fronts at that point. Your extra 1/2" of BS will push the tires more inside and more likely to hit the cab mount. I just don't see how you will run that set up and not need a CMC.

 

He’s worried about hitting the UCA not cab mount. I do believe with 285/70 you might be ok. I’m 285/75. And if they were a little shorter I don’t know if I’d rub. I just barely hit them

 

This is directly from the JBA website.

"Please Note: 32.5" and larger diameter tires need aftermarket wheels with less then factory wheel back space.

• LT285/70R17 (32.7" x 11.2") tire on 17 x 9 wheel, -12mm offset (4.50" backspace)
• LT285/70R17 (32.7" x 11.2") tire on 17 x 8.5 wheel, -9mm offset (4.30" backspace)
• LT285/70R17 (32.7" x 11.2") tire on 17 x 8.5 wheel, 0mm offset (4.75" backspace)
• LT285/75R16 (32.8" x 11") tire on 16 x 9 wheel, -19mm offset (4.25" backspace)
• LT255/85R16 (33.10" x 10") tire on 16 x 8 wheel, -12mm offset (4" backspace)
• LT315/70R17 (34.4" x 12.4") tire on 17 x 9 wheel, -25mm offset (4.00" backspace)
• Any tire that is 32.2" diameter and smaller there is no fitment problem.

Tire sizes that work well with the JBA UCAs

• 265/75R16 tire 31.6" x 10.4" on factory wheels
• 255/75R17 tires 32.1" x 10" on factory wheels
• 275/65R18 tires 32.1" x 10.8" on factory wheels
• Any tire that is 32.2" diameter and smaller there is no fitment problem."

 

Sorry OP, but would factory offroad wheels not rub with 33s at 2-3" lift? Haven't been able to find this answer.

 

Understand this says... LT285/70R17 (32.7" x 11.2") tire on 17 x 8.5 wheel, 0mm offset (4.75"backspace).
Knowing that Nitto Ridge Grapplers are 11.50 wide not 11.22 is ny concern. I mean if I have to get new wheels with more backspace I could easily get rid of what I currently have but would really rather not.

 

sorry to bump an old thread but am thinking about getting jba ucas. Does anyone know if this table is actually accurate? Why would a 255 tire require the same back spacing as a 315 tire?

 

Totally different size wheel, wheel width, and offset....back spacing may be the same but literally nothing else

 

For sure but that's kinda my point. 4" backspacing is the same distance from uca to inside edge of rim regardless of wheel width. So why would a tire that's narrower and shorter (255) need the same clearances as a 315? Just trying to figure out if jba's will work for me.

 

Since you deleted your next response. I’ll try to help by wording the reply differently.

no matter what width tire you are running at a certain point the backspacing must be greater than X to avoid rubbing the upper control arms. Wider wheels and tires require a lower offset wheel to maintain the same or similar backspacing as a narrower setup.

 

sorry about that, it double posted on my end then when i tried to delete the extra comment it deleted both

 

Ok understood but maybe I'm just being dense, and i am a bit out of it today, but if you have a 255 (10.4") and 315 (13.64") both mounted on a rim with 4" back spacing (regardless of rim width or offset) the 315 tire will be 1.62" (13.64/2-10.4/2) closer to the uca. So why would that distance not be accounted for in the recommended backspacing?

 

I just picked 2 options from the list above. Notice how the tire stays in roughly the same position on the inside yet the outside pokes out farther.

 

yup makes sense, but larger tire closer to suspension. Thanks for the replies, btw

 

idk fuck it, i'll just take your word for it

 

I know it's an old thread, but...

That tire calculator JBA uses gives section width.
Nitto gives overall width.

 

I saw this thread and I didn't have pics to answer. Now I do.
I followed JBA's rec. Here is my set up: JBA UCA, Toytec Aluma Lift, 17x9 -12 offset 4.5 BS, Toyo AT3 285/70/17
Lots of room on the UCA. Not so much on the rear fenderwell.