TRD Pro wheels with JBA High Caster UCA, Westcott Designs Lift - Clearance and Fitment

I've searched the forums for something similar to my parts/rig setup, but to no avail. I think I am on the right track with this, but would like some input from any/all with experience.

Basically, my stock UCAs shit the bed at 36k miles on the bushing side (i dont baby my truck and i live down a long pothole filled dirt road - im sure it's a contributing factor) so I am replacing them with JBA High Caster UCAs.

I have 285/70/17 KO2 all around, on the stock TRD Pro wheels. I understand there is minimal clearance or even a potential for impact/rubbing due to the info presented on their website. See below:

285/70 R17 (32.7" x 11.2"), or 285/75 R16 (32.8" x 11.2") 11.2" wide tire:11.2" wide tire, if the wheel is 7.0" wide, you need a 4.00" backspace or smaller to clear the JBA ucas.
11.2" wide tire, if the wheel is 7.5" wide, you need a 4.25" backspace or smaller to clear the JBA ucas.
11.2" wide tire, if the wheel is 8" wide, you need a 4.50" backspace or smaller to clear the JBA ucas.
11.2" wide tire, if the wheel is 8.5" wide, you need a 4.75" backspace or smaller to clear the JBA ucas.
11.2" wide tire, if the wheel is 9" wide, you need a 5.00" backspace or smaller to clear the JBA ucas.
11.2" wide tire, the above will have .125” tire clearance to the JBA arms at full lock of the steering wheel, with that wheel and tire setup. If you need a smaller backspace a wheel spacer is needed, the most common spacer is 1.25" thick. This is only tire to a-arm clearance, you may still need to do body mount chop and clearance the wheel wells and front bumper.

As the TRD Pro wheel is skinny at 7.0" width, I would I assume I will be cutting it close on clearance. As a result, I see people going with wheel spacers to decrease backspacing (i think that is how it works). Am I correct in assuming by adding hub centric wheel spacers, I can get below the 4.0" inch backspace figure? Using a calculator, I am seeing that the stock TRD Pro 7inch wheel has about a 4.5" backspacing.

If the above is true, it sounds like I would need just over a half inch spacer on the hub to mitigate any contact. Am I on the right path with this line of thinking?

Any and all input is appreciated. I know this is a common topic across forums, but I am new to working with wheel offsets and backspacing.

 

I have jba uca with 285 70 17 and 17x8.5 with -12 offset. Here's a picture of the clearance with is like 2" or more

 

Thanks for the input.

I think that negative wheel offset helps give you that nice clearance. It's making me think more and more that I need a spacer of about 1." At least they are cheap and if they aren't needed, I'm sure I can flip them new in box.

 

TRD Pro wheel is +5mm offset? That's about 0.2". So you'll have about 4.2" backspacing.

 

You could order spridertrax off Amazon and if they aren't needed just send them back. You SHOULD have enough clearance though.

 

Love all the input and help. Great idea on the return if not needed. I will find out this weekend when I do the UCA install. Maybe I can report back and my experience can help someone else.

Thanks!

 

Please report back. I've seen this question (if jba uca will work on trd pro wheels without spacers) asked more then once before.

Also id order a tube of the grease jba offers.

grease the bushings, then put the 4runner on the ground then tighten the uca.

 

Check through the full steering range. The tire sidewall can rub against the curved part of the UCA front tube when steered, even when everything clears with wheels straight ahead.

 

Appreciate your extra info. I am going to do brake job and UCA's this weekend and Ill report back.

 

Okay, back with some intel.

I completed the UCA job, which was pretty easy if you have a second set of hands to help. There is no rubbing at all with my KO2 285/70/17 on the new UCA. Obviously it needs an alignment, but it looks like I lost caster (for now) as tire is closer to the body mount than it was before. About 5/8 inch clearance to body mount at full lock. Also noticeable is when you have the wheels turned full lock, the tire comes quite close to the tubular forward portion of the UCA. About 3/4 inch clearance at full lock. From ball joint end of the UCA to top of tire was approx 1.5 inches. The tire sidewall that bulges out is closer, but I don't see any type of contact yet. The only real problem that I ran into was the ABS line brackets. While the JBA UCAs are drilled and threaded for the bracket bolt, I decided to bend that bracket to give the line more clearance. Things get pretty tight at full droop, so I may want to add a longer section of hose in the near future, and certainly before it makes it way onto a lift again. Another point, at full droop the UCAs do not touch the spring in my TRD Pro Fox suspension with Westcott Designs lift. The stock UCAs did at full droop, which i noticed today (no rubbing or marring). All my vibrations and clunks are gone now, which is great because I have been trying to track them down for months.

See below for photos of clearance on a stock TRD Pro +4 offset wheel. I know the angles aren't the best, and I haven't tested a higher compression of the spring yet, so if problems arise, I will report back. I will try to get a shot of the clearance between the tubular front portion and the tire. I'm not worried about the clearance, its slightly over 1/2 inch, possibly 3/4. I drove the truck HARD (to test out clearance and possible conflicts) before checking all components for signs of rubbing. None.

Fun project. If any issues arise, I will keep this updated as I know a lot of others could be running this UCA and lift combo, and 285s are common.






Wheels Straight


Wheels turned to lock

 

Just as you mentioned, I saw the front of the UCA to be the tightest clearance. To be honest, I forgot that you mentioned it until I reviewed the thread.

 

Im still learning how to use the forums, so just shooting a reply in case i missed anything noteworthy in my write up.

 

Caster gained through the UCA brings the top of the tire closer toward the rear. Caster gained through the LCA brings the bottom of the tire farther away from the rear. The JBA UCA gained you caster and made clearance worse.

For the ABS wire, if it's pulled too tight at full droop, you can open up the OEM bracket with pliers, slide the wire a bit, and cinch up the bracket. Put some over wire sections that may chafe. Toyota uses plastic split loom everywhere in the vehicle.

 

Yeah after I installed the jba uca, I rubbed on the body mount. I did a body mount chop. Now I have a ton of clearance.

Glad your install went good and they worked with your wheels.