QA1 Tech Tip: Benefits of Control Arm Geometry

We’ve all heard these hype words – “tubular control arms.” They’re buzzwords in suspension, just like coil-overs. Do tubular control arms live up to the hype? Are tubular controls arms actually worth your time and hard-earned dollars? What are the true benefits of tubular control arms? Let’s dive in and take a look!

Right off the bat, a tubular control arm is going to be all new. No worn-out bushings cracked mounting points, sloppy ball joints, or ugly appearance. Yes, QA1 tubular control arms are worth it!

Improved Geometry

There are two major things that QA1 tubular control arms help with: caster and camber. Camber is how much the top of the wheels lean towards or away from the car. Caster is a little harder to see when looking at a car; in essence, though, caster is an imaginary line that goes from the top ball joint through the bottom ball joint.

Camber is crucial for keeping tires planted on the road. Imagine driving down the road and taking a hard-right turn. What you want is for the wheels to lean towards the right to help keep those tires planted. However, in many applications, such as GM A-Bodies, the opposite happens. When you take that hard-right turn, the wheels lean to the left. Our arms are designed to correct these issues through changes in the physical dimensions of the arms.

Why is caster important? As we mentioned, caster is this imaginary line that goes from the top ball joint through the lower ball joint. That’s what helps keep your car driving nice and straight down the road. In more aggressive racing applications, caster also helps improve the camber gain.

Back 50 years ago, when these cars were new, they used bias-ply tires, but modern tires are radial. Without diving into tire manufacturing, bias-ply tires love negative caster, or the upper ball joint in front (towards front of car) of the lower ball joint. Radial tires love the opposite – the upper ball joint behind (towards rear of car) the lower ball joint.

The improved geometry helps the car track straight while heading down the road. The only way to accomplish this is by utilizing a tubular control arm where the geometry is built in. No amount of shims on a stock control arm will get the geometry corrected to modern standards.

Bushings

Let’s start with the bushings. Original bushings are rubber and meant to isolate the suspension from the driver to give an ultra-cushy ride. The downside to rubber is it’s very soft. When you are launching the car or going around a corner and pulling G-forces, that rubber is giving. On a control arm it could give quite a bit and cause pretty drastic changes to the caster and camber of the suspension.

QA1 fixes that by utilizing a polyurethane bushing or a Delrin bushing. A polyurethane bushing is firmer than rubber to help reduce flexing but will still give way if you hit a pothole driving down the road. A Delrin bushing is even firmer than a poly bushing but has a little bit of give. The Delrin bushings are a step below a rod end, where they perform like a rod end but have a bit of give to let the car have some street manners.

Whichever bushing you go with, the new tubular arms have grease zerk fittings in them to ensure a squeak-free ride.

New Ball Joints

A worn-out ball joint can fail and cause disastrous consequences. We use high-quality ball joints that freely move. Cheaper ball joints are stiff and don’t allow the suspension to go through its range of motion as easily.

Another benefit of QA1 ball joints is that we increase the height of them in many applications. For example, in the GM A-Body, the spindle height (the distance between the upper and lower control arm) is too short. This causes geometry issues where the tire ends up leaning away from the car in a corner as opposed to leaning towards the car. We utilize taller ball joints that fix these issues while allowing you to maintain stock spindles.

Appearance

Lastly, tubular control arms look great! They are welded and powder coated, and they let people know you have a performance handling ride! While stock arms are bulky stamped steel and not very appealing, QA1 tubular control arms will make your suspension look as good as the rest of your car!