SPC UCA alignment (help me understand)

I have been trying to get the maximum clearance after going with 255/85/16. I have 887's and SPC UCA's up front.

My numbers aren't bad, but I believe they did the adjustment for castor backwards. I know they made the adjustment from the LCA. My bad for assuming that the tech would understand when I told him I got adjustable UCAs. So I just want to clarify a few things before i take it back in.

1st-LCA adjustment. Is it best to leave it in a neutral position, or max it out then adjust for castor. Or is it best to center the wheel in the wheel well, and then make the adjustments.

2nd- This seems obvious, but would you set the castor and then the camber using the slide once the castor is set? I would think that you could lose the camber by adjusting for castor if you did it the other way around.

Can someone explain why 3 degrees of castor seems to be the golden number? I have fought with the lead tech a couple of times about the castor and he thinks I'm crazy when i tell him I want 3 degrees.

Thanks in advance for any genuine replies.

 

Sub'd for when I do get lifted.

 

Since you live in Clarion, go to Newby Wheel Alignment in New Bethlehem. They have adjusted mine twice now and did exactly what I asked. Couldn't be happier with them.

 

I am going to give Good Tire another shot once i get a handle on exactly what I need. I have heard of a few bad experiences with Newbie, including the shop that installed my lift.

A friend from high school does most of the alignments and has always been a toyota guy. He will take care of it, i just need to provide him with what needs done.

Since you seem to have knowledge of the SPC and alignment, am I on the right track with my thinking or in left field?

 

The install sheet usually references the install plate to lift/caster desired.

I like a balance of caster and camber, 3 is a lot on a lifted Tacoma, I'm usually happy when I get 2.5 with upper arms.

I usually set the plate, set the lower arms to neutral then see if I can get what I want. I really like 2.5 caster and just a touch of positive camber with lifted tacomas. I go max toe if they have big ass tires.

 

I didn't keep the install sheet from the shop that installed the lift. I did just find one online that I printed, so I could show the tech exactly how they work.

Hoping to be able to gain a little more clearance so i can run my mudflaps again or get some aftermarket. Right now i am hitting my fender flare when stuffing. I guess that should be the question asked. How do I complete an alignment to achieve the most clearance with UCA's.

 

I'll have to check my numbers.

 

Read this to know how to set LCA's for max caster & set UCA's to neutral (+2°).
https://www.tacomaworld.com/threads/how-to-do-an-alignment-at-home.252256/

 

The amount of caster that you need is partly personal choice. In my opinion, you can't get too much caster on a lifted Tacoma. I have tried caster settings from 2 to 4 degrees. I drove for years on 2 degrees. I prefer at least 3. The problem is that on the lower settings, the steering will feel lighter. The truck will hold it's line of travel as well. Around town, this is not noticed so much. I spend a lot of time on the highway, and keeping the truck on the road takes considerably more attention. That makes driving more tiring. I actually liked 4 degrees the best, but it does move the wheel back in the wheel well. The best point I could find was with the SPC set in the mid position, maximize the LCA for caster, get as much camber as you can with the SPC slot, then fine tune the camber with LCA. On my truck it yields about 3 degrees. I prefer 0 camber, and toe set to the high side of factory spec. If you go higher on camber or toe watch your tire wear carefully. My tires wear very even with regular rotation

 

This exact process got me 3.9* DS and 4.4* PS, with the difference being on purpose for the crown of the road.

 

The first thing you have to understand is while the LCA adjustment and the UCA adjustment both can control Camber/Caster, the end result is different. The blue center line in this picture goes out the window. I have one UCA set at a more positive position and the other at a less positive position. The one side rubs the cab while offroad at heavy compression and the other side rubs my arb bumper offroad at heavy compression. The ARB bumper affords me more room towards the front than the stock bumper does so I need to set the UCAs so that it pulls the tire forward and then cut some off my bumper. Increasing Caster at the UCA moves the tire rearword, where increasing Caster at the LCA pulls the tire forward towards..

 

This was my understanding, but I am ignorant about alignment, and what adjustments change what. I do not know where to start or what i need to know to make sure I am getting what i paid for. I know I want 3 degrees of castor, I am about there now and like the feel of the steering. Basically I am just looking for knowledge to get my set-up with the most clearance as possible. I am hitting the fender flare at the rear of my driver side. Is that because of my alignment or taco lean? I cannot reproduce the issue on the passenger side.

Looking at your diagram I am assuming i need to get 3 degrees of positive castor with the adjustment made at the UCA. Thanks for helping with this. I just want to make sure that I get it right before paying for another alignment.

I am assuming that there is a specific order to make the adjustments. To me is makes the most sense to make the castor adjustment first, since you have to loosen the nut considerably to adjust the plate. Then I would assume that the camber would be adjusted since it is just a slide, and would have to be loosened enough to adjust the plate. Then I've always been told that the toe is the last thing to adjust.

I really wanted 0/0/3 degrees as the consensus was that was a good set up for 3" when I added the lift. Now it seems as if I need to have some camber and 0 is not a good number.

Thanks for the info.

 

I think you mean opposite. Increasing the caster at the lca moves the tire forward and away from the cab mount. Increasing caster at the uca moves the tire rearward and closer to the cab mount.

 

My experience with alignments and SPC UCA's.

Learn how to do it at home so you can play with what you like best.

High caster numbers (2.5+deg) will cause a VERY big propensity to pull with road crown. I have ended up around 2.2* Caster, .02* positive camber and ~ .01* of toe. Truck drives arrow straight, steering is light.

 

I always thought this was the case as well

 

You're backwards.

 

Please see above