Most UCA's Have a huge design FLAW!

Not really. I don't plan on launching the truck. I'm ordering bigger bump stops.
I know that at full stuff the tire can come into contact with the top of the fender well. But again I don't plan on launching the truck anytime soon, and this would happen no matter which UCA's you use.

 

I also plan on lifting my truck about 1/2" more and reinstalling my front mud flaps. (That might rub) But shouldn't be too bad.

 

That's what I'm saying. Regardless of UCA or castor on big hits on stock bump stops you will rub the pinch weld, but that doesn't affect daily drivability. For your 285s, I just needed to cut/pound the area where the mudflap was. For 35s I have to do the whole thing and still get bigger bump stops so I don't rub the inner fender until I tub.

 

True! You'll probably need to do a CMC also.

But this isn't about that. This is about the Approach of UCA manufactures to solving alignment issue when lifting our trucks.

The only point of this thread is that adding Caster is Not the best way to resolve the alignment issue's with a 3" lift. Because it creates additional problems. (that's the "Flaw")

 

Understood and I agree with your point that most aftermarket UCAs will reduce clearance and make rubbing worse. Just nitpicking when people say like "it doesnt rub at all if you just do this..."

 

No rub on 32’s

 

Well hopefully after I get the SPC UCA’s installed, it’ll solve my rubbing problems.

 

Mine are setting F, feels like 2 degrees or so of Castor, -1.5 camber, pinch weld pounded flat, normal cmc, superbumps. I just barely scuff the inner fenders, and scuff the firewall at full stuff and when the Lca bushings flex out all the way (front tire bound into a rock). Just switched to 2" spacers instead of 1.25s, so will probably have to hammer the firewall a hair more.

 

Trying to calculate if my Ironman UCA's are all the sudden a danger to society like:

 

Totally agree. I recently bought my 2021 Tacoma so I am new to the whole suspension lift topic. I am a mechanical engineer and a lot of what people do when they lift their trucks does not make sense to me.

Why don't manufactures make a Lower Control Arm with the ball joint moved forward to add caster back? To me that would be a better approach. It would add caster and move the tire forward for better clearance.

 

That would be an awesome approach to this puzzle! Seems like someone came up with the UCA fix and decided to Stop right there and declared it a win? Even if it caused so many other issue.
LCA’s would be a great "thinking outside of the box" solution to this problem. Something people need a fresh perspective to an old problem.
LCA's are actually easier to swap out than the UCA!

EDIT: I was just thinking that replacing the LCAs would still leave the poor angle of the UCAs after a lift. Also the loss of camber is another issue that I don't think can be properly corrected with the LCA. Because it would move the tire outward more and may protrude outside the fenders more.
But this still opens the door to a "Better Mouse Trap" we need to continue to brainstorm. May be a combination of both is required?

 

I’m in here to learn, and I appreciate posts like these. I currently have a set of JBA UCAs I am about to install. I was under the impression adding positive caster moves the wheel/tire more towards the front (away from the cab mount) of the vehicle. Is this incorrect?

 

If you move the ball joint position on the UCA to the front, that decreases caster. All of the non-adjustable UCAs that I've seen move the ball joint position to the rear to increase caster.

My long term plan is to get a high clearance front bumper to make room for the tire in the front. Install SPC UCAs and run them in the max forward position. Adjust the LCA cams to the max forward position. Adjust the camber with the SPCs. I am going to see if this will clear a 255/85R17 (35") tire.

There are lots of people running skinny 255/80R17 or 255/85R16 (33") on a stock truck with stock wheels with no rubbing. My thinking is if I run a skinny 35 in the max forward position it will clear the cab mount and rear fender. It might hit the top of the fender liner at full stuff, but that is easy to fix.

 

Here is an of the out of box solution. Linked the 3rd gen for you but 2nd gen is available too.
https://jdfabrication.com/products/tacoma-2016-lower-arm-pivots-899-99

Entire thread on it below. Starts about here :
https://www.tacomaworld.com/threads...avel-and-934-cv’s.626274/page-9#post-21680758

 

I've seen those. Really nice piece, but too much work to install work for me.

 

@toku58 Any advice on this? I have JBAs I am about to install which have 3 degrees of caster built in. Positive caster, from my understanding and research, is when the wheel/tire is moved towards the front of the vehicle.

This is straight from JBAs website:

“What is more caster? More caster is the top ball joint moved back toward the cab and the lower ball joint moved forward away from the cab the angle between the two ball joints is the caster. We have moved the upper ball joint back to give the alignment tech the ability to move the lower ball joint forward. So with the lift kit, you get between 3 & 4.5 degrees caster. Giving the vehicle ideal handling offroading and on the highway!”

I am running a larger than stock wheel and tire set up (& aggressive offset) so am putting these in with plans of being able to adjust the wheel/tire away from the cab for additional clearance and as well as a better overall alignment.

 

Adding caster with the UCA moves the tire back towards the firewall a small amount. Adding caster with the LCA move the tire forward towards the bumper a medium amount. You will gain more clearance by moving the LCA forward than you would moving the UCA forward.

Both caster and camber are lost when lifting.

If you have SPC's and set them in the forward position, then adjust the LCA all the way forward with the cams, you will still have low caster, even if it is "in spec". The specs for a Tacoma are between 1.2-2.8 degrees if I remember correctly. The best setup for handling off-road is 3+ degrees, though 2.5 degrees is not bad by any means, it's just not the "best".

If you use the cams to adjust the LCA all the way forward, you will be twisting the rubber bushings, causing some premature wear. If you don't off-road much, this won't be a problem, but for those who do off-road a fair amount, you will blow through bushings somewhat regularly.

JD fabrication does make a kit that solves several problems, but it's main benefit is the ability to move the LCA forward up to an inch without binding the LCA bushings. However, it is a fair amount of cutting and welding to install. https://jdfabrication.com/collections/05-15-6-lug/products/tacoma-05-18-lower-arm-pivots

HOWEVER; Regardless of where you move the tire in the wheel well, the wheel well does NOT get bigger. I see and hear of lots of people claiming their tires don't rub with 33's etc. This depends entirely on how you use your truck. If you drive around on pavement, then likely, they will rarely, or possibly never rub. If you drive off-road, and flex the suspension or hit big bumps, especially with the wheels turned, you WILL rub with 33's, and I won't even get into what is required to properly clear 35's. The only way to clear bigger tires throughout the full range of motion, turning and suspension travel, is to cut, trim, etc. I doubt many, if any people who claim they clear 33's with no rubbing have ever pulled their coils and cycled their suspension properly to check.

I am just talking about how to clear them properly, at full bump, with the steering turned all the way. If you limit your steering or your suspension with longer bump stops, this will stop the rubbing, but at the cost of a worse performing vehicle.

None of this is new information, but there is a lot of misinformation out there, including in this thread. For credentials, I do own a shop that works exclusively on off-road Toyotas and do this for a living every day. I also have 37" tires on my Tacoma with no rubbing at full compression, lock to lock. I actually have cycled suspension properly with many suspension setups and different sized tires. The wheel specs, width, backspace, offset, make a huge difference on what tires clear.

 

Good post here. Thanks for that info, always nice hearing from a credible source. So are my JBAs going to be of benefit to me with a 2” lift up front from Bilstein 6112s or is a different brand better or it almost seem according to the OP I’m waisting my $$ on aftermarket UCAs. I have seen plenty of alignment sheets of people with JBAs showing 3-4 degrees of caster and perfect toe and camber. A final positive caster # is the wheel moving forward in the wheel well correct? Before reading this guys post I was under the impression getting 3.5 positive caster would be no issue. I will be running a 285/70/17 and do plan on doing a CMC and trimming/molding of the plastic in the wheel well.

 

Basic answer to this is that aftermarket UCAs that add Caster move the range of articulation towards the cab mount.
This is why I like SPC.
Because you can keep the OEM caster (By using setting "G") and use their UCA to correct the "Camber" (By using the sliding ball mount)

at this time with the products I've seen this is the simplest way to achieve the best clearance.
But like it was stated, the wheel well on our trucks are only so big. You still may have rubbing issues due to the fact that all wheels and tires are made with a "rainbow" of options of size and offset.

But the point of this thread was to enlighten people that adding Caster to correct a loss of Camber issue from lifting the truck is a bad idea.
You would be best off keep your stock UCAs!

 

Just skimmed through this quick. This is why I started drawing these up a couple years ago and just did the first ones past fall. So far only minor changes to them , for the next set . Truck drives great compared to stock arms with a lift. Link from before have some more updates on what actually hits. Still have to put a 35 on and see if it clears in front and the 1-2-10-11 o clock area.

https://www.tacomaworld.com/threads/how-to-fit-bigger-rubber-my-way.742142/