Upper Control Arms

Published by John on 21st Jun 2020

The Ultimate Guide (2021 Update)

In this article where we are going to cover a few important points about upper control arms (UCA).
We are going to try and answer some of the most common questions you may have.
Please bear in mind this is a general overview as suspension systems vary greatly between different model vehicles.

What are suspension control arms and what do they do?

Upper and lower control arms are critical components on IFS vehicles that dictate the alignment of the road wheel as it moves up and down with suspension travel.

They firmly hold the steering knuckles, axle spindles and road wheel to the vehicle while allowing the suspension to flex and maintain accurate steering geometry.

It’s all thanks to the ball joints and rubber control arm bushings that allow this movement.

Many controls arms (either upper or lower) have a limited range of adjustment, mainly to allow for setting camber and/or caster during a wheel alignment.

Camber is the angle of the tire with respect to the vertical axis of the car.

Positive camber is when the top of the tire is leaning outward, and the bottom of the tire is inward.

Caster is the angle of the tire with respect to its steering axis (where it pivots when turning the steering wheel) against vertical.

It is considered positive if pointing toward the front of the vehicle and negative if pointing toward the rear.

Why upgrade upper control arms?

If you have a suspension lift kit, please understand that you have just changed your 4WD suspension and steering geometry.

Your good-looking lift kit, other than allowing you larger tyres and more ground clearance, it has also lifted your chassis and body up and away from the mounting point of your wheels and tyres.

Solid axle vehicles have a similar problem with the front diff rolling but is easily corrected with some off-set bushes in the trailing arms.

With IFS vehicles you need to be careful fitting a suspension lift as the original caster and camber specifications are pushed outside the acceptable limit.

A lack of enough adjustment combined with typically short control arms causes your vehicle to lose camber/caster.

This can cause your steering to become vague (tracking) with an out of control feeling.

These issues can also greatly accelerate tyre wear costing you more money in the short term.

To make things worse, fitting larger tyres can hit suspension components and even make contact with the chassis which is a problem that nobody needs.

From the factory, most IFS 4WD's only come with a small amount of adjustment; however, this is reduced when you add a suspension lift to your vehicle.

This means when you do a wheel alignment, there will not be any adjustment available to set your vehicle’s camber or caster correctly.

And please know that your vehicle’s instruction manual wheel alignment specs page does not take into consideration raised suspension or tyre size.

Another serious issue found when lifting a vehicle with IFS is running out of movement in the ball joints.

This is called ball joint binding and is caused by changing the suspension geometry to a point where the ball joint simply cannot move to a larger angle.

The ball joint itself comes into contact with its own housing effectively reaching its maximum angle.

While the ball joints may look okay parked on flat ground when under conditions involving significant articulation (lots of suspension travel/extreme offroad) this can cause the ball joint to separate (pop out of socket) with the road wheel and steering knuckle coming loose from the control arm

Far from ideal!

So, what to do?

Simple:

Install modified upper control arms to your IFS 4WD

Luckily here in Australia, we have a choice of quality aftermarket upper control arms from well-known brands that can resolve all these issues.

They have been redesigned to provide a better geometry for lifted vehicles, allowing the use of the standard adjustment for setting wheel alignment.

They will effectively help to get the maximum performance and lifespan from your suspension, steering components and tyres.

The positioning of the ball joint allows it to sit in a more neutral position providing a full range of travel as per OE specs, effectively eliminating the binding issue.

Tough Dog and Blackhawk by Roadsafe are among those

Here is a brief introduction of both:

Tough Dog upper control arms

Tough Dog upper controls arms features are:

Fixed position arm with increased caster (built-in)
1020 grade forged ball joint housing and end-rings (bush end)
Heavy-duty, greaseable ball joints of OE size for easy replacement
Grease-free synthetic elastomer bushings
Free-pivoting bushings remove the chance of binding
increased clearance to strut/coil spring at full droop
increase strength exceeding OE versions

Blackhawk upper control arms (by Roadsafe)

Roadsafe upper control arms:

Fixed arm with increased caster (built-in)
OE style/size rubber bushings
OE style/size ball joints.
Increased strength over OE

A lot goes into the design and manufacturing of an upper control arm kit.

Thousands of dollars are spent in computer modelling, prototypes and testing before going to the market.

Here in Australia, they need to meet or exceed OEM specifications with the appropriate paperwork and engineering reports to receive ADR compliance (Australian Design Rule)

Although designed and manufactured to be ADR compliant this can be somewhat confusing as there is no Australian Design Rule for specific products like upper control arms

Roadsafe have ensured their control arms mount to standard fitment positions, have not moved or changed any of the mounting points and used OE specifications for bushings at the chassis.

More detailed information is available upon request.

Not all upper control arms are created equal

Different users (and uses) - different needs

Some aftermarket control arms are fully adjustable in both camber and caster; others have spherical joints at both ends.

Tough Dog and Blackhawk UCA’s use a fixed position ball joint with heavy-duty, OE specifications for the ball joint itself

Both brands specifically chose a fixed ball joint for off-road applications as the ball joint receives a large amount of bump / shock loads.

Over time this could knock an adjustable ball joint out of position.

These brands provide standard features such:

3 or more degrees of fixed caster correction which is the perfect amount of correction required for lifts ranging from 30-70mm
A fixed amount of caster offers the ability to use the factory adjustment to fine-tune the caster required for the vehicle's lift
Camber adjustment to meet OE specs
Maintain OE specification ball joint & bushings – you can use genuine replacement parts or aftermarket OE in case you need to replace a ball joint or bushing (OE spec bushing for Blackhawk only)
Positions for factory mounting of brake lines
Increased strength compared to the OE design
Heavy-duty long-life ball joints

All Four x 4 Spares stocks Blackhawk upper control arms and Tough Dog upper control arms suitable for a wide range of vehicles. Here is the list: