Control Arms for Performance, 4x4 and Service
The control arm links the wheel carrier to the body and defines how the wheel moves as the suspension travels. When ride height changes, this geometry changes too – and with it handling, steering feel and tyre wear. In addition to bushes, SuperPro has offered complete control arms since 2013 (product line Roll Control).
Control arms for performance cars
When a car is lowered, the arms no longer sit parallel to the road but angle up towards the wheel. The roll centre drops, the body leans more in corners, and camber and caster leave their intended range. Thicker anti-roll bars only mask this – it is better to fix the cause.
- Adjustable control arms (camber, in some cases roll centre) bring the geometry back into range after lowering and allow extra negative camber for more cornering grip.
- Ball joints with roll-centre correction have a longer stud that puts the arms back into a more parallel position. The roll centre rises again and body roll is reduced.
- Bump steer kits (modified tie rod ends and ball joints) stop the wheels steering on their own as the suspension compresses.
- Supaloy aluminium arms reduce unsprung mass. The first Supaloy arms in 2013 were the wishbones for the VAG PQ35 platform (Golf 5/6).
- Duroball bushes combine a metal shell, polyurethane and a uniball joint: the arm pivots even more freely and the wheel keeps constant road contact.
- Eccentric bushes in the rear mount of the control arm increase caster – more steering weight and self-centring, delayed understeer.
Control arms for 4x4: lift and its consequences
Raising a 4x4 (bigger wheels, winch, bull bar, roof load) often pushes the geometry well beyond the factory adjustment range. Typical results:
- reduced caster: light, vague steering, less self-centring, unstable straight-line tracking;
- changed camber: uneven tyre wear and less grip;
- alignment values that can no longer be brought within the manufacturer specification with the standard adjusters.
Bushes help here too: eccentric bushes can win back part of the self-centring torque lost through the caster reduction. For larger corrections, control arms are the better choice.
Solution 1: control arms with fixed geometry correction
Upper arms with built-in correction are designed for a typical lift of about 50 mm. Depending on vehicle and lift height they add roughly +2.5 to +3.5° of caster and allow up to 1.5° more negative camber. They are “fit and forget”: no further adjustment of the arms is needed, and they are the economical solution.
Solution 2: adjustable control arms
If the fixed values are not enough – for a larger lift or a different wheel and tyre combination – adjustable upper arms offer a much wider range of caster and camber adjustment and can be set precisely for your build.
In both cases uprated ball joints and SuperPro polyurethane bushes are used. A wheel alignment is required after fitting.
Complete control arms for service and repair
When an arm is worn out, replacing the complete assembly often makes sense: bushes and ball joint are already fitted, there is no need to press out old bushes, and the quality of the joints is repeatable.
- Material: SuperPro polyurethane is polyether-based and bonds chemically to steel and aluminium, so shell bushes sit as firmly as original parts.
- Durable: unaffected by oil, solvents, heat and UV, keeping its feel over time – without the noise, vibration and harshness (NVH) typical of inferior polyurethane.
- Experience: SuperPro has built bushes since 1983 and engineers and tests everything in house.
After fitting
- Wheel alignment before and after the job (note the starting values).
- Tighten all arm bolts to the manufacturer’s torque with the vehicle at ride height.
- If you change ride height or axle geometry, observe national rules on approval and registration.