Hello all of you! This is Braeden again with another Frequently Asked Friday! Lets goooo!
Today I wanted to talk about Upper Control Arms. In our shop we only work on Toyota’s, so that’s what I’ll be going over here, but the same general information applies to most independent A-Arm front suspension.
So the upper control arm or UCA for short, is a part of your front suspension. In a double A-Arm setup, you have a lower control arm and an upper control arm.
Typically, you’ll find that people talk about changing their UCA when they are changing the suspension on their vehicle and adding lift. There are a few reasons for this!
The first reason to change your UCA is because, through the range of your suspension’s travel, your alignment changes, especially the Caster.
I’m going to make another video in the future about alignments specifically, but for now, all you need to know is that having a higher positive caster makes your steering more stable and turn into corners slower. Having a lower or even negative caster will make your steering very twitchy and your steering wheel won’t return to center as well. For off road, we usually try to aim for a caster somewhere between 3-4 degrees.
So as your suspension droops out, the geometry causes your vehicle to lose caster. The same applies to lifting your truck, which also causes you to lose caster.
A big misconception is that higher caster equals more clearance for big tires. This isn’t really the case;
What an aftermarket UCA does is move the upper ball joint out and towards the back of the vehicle. This increases the amount of caster you can get, while also adding back the camber that would be lost, correcting for the higher ride height. I recommend changing your UCA’s for 2” of lift and strongly suggest changing them for 2.5” or more. However, they are mandatory on many suspension setups for the next reason!
The second reason for upgraded UCA’s is for additional droop. Most aftermarket suspension kits, especially the high end setups, allow for more down travel than what the stock shocks can do. However, the stock UCA limits this travel for two different reasons. One; the ball joint doesn’t have enough range of movement, so it starts to bind; and Two; there isn’t enough room on the inside of the arm, so as the suspension droops out fully, the stock UCA will contact the coilover.
The third reason to swap UCA’s is for additional strength.
There are 3 main brands of UCA that we sell in our shop. We sell SPC, JD Fabrication, and Total Chaos.
SPC UCA’s are cool because they have a greasable ball joint that can be adjusted. This allows you to fine tune your alignment, as well as use your alignment to make more clearance for larger tires easier.
However, in my experience, if you wheel hard and are driving off road a lot, the SPC arms can’t quite handle the abuse. For most people they will work great, but for those people that are going quickly down rough roads on a very frequent basis, the SPC ball joints tend to develop play. I’ve seen them need to be replaced after around 9 months of hard use. Another brand, JBA, also has a similar issue, and I’ve replaced a lot of JBA ball joints because they wear out so quickly.
Total Chaos makes a very strong UCA. They use polyurethane inner bushings, and a uniball outer joint. If you’re going for strength, these are a solid option. However, depending on where you live, they might not be the best choice. Here in BC, Canada, we get a lot of rain, and harsh winters with salty roads. The exposed uniballs on the TC arms require a lot of maintenance and care to be kept running smoothly in those kinds of conditions. The poly inner bushings also tend to squeak a LOT. We have a hard time recommending the TC arms to any of our customers, or for anybody that lives in a similar climate to us.
JD Fabrication makes a really great UCA. They have 2 options, depending on how strong you want the arms to be. They have one option that uses stock rubber inner bushings. These are great because they simply just work. They are quiet, and reliable. The other option is to use uniballs on the inner pivot. JD has custom seals made to try and keep as much mud and grit out of the uniballs as possible, which helps keep them working, even in harsher climates.
For the outer, JD uses what’s called an EMF joint. These are made in Canada, and are a uniball, but are sealed on the top, with a grease port. This is kind of the best of both worlds, between going with the greasable ball joint, and the strength of a full on exposed uniball.
But this is just what I’ve found in my own experience. What UCA’s are you running on your truck? What’s been your experience with them? If you’re still just planning your build out, what kind of UCA’s are you leaning towards getting? Let me know in the comments! And as always, if you liked the video, give it a thumbs up, but even better, subscribe so you don’t miss the next FAF!