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Superior Engineering SuperFlex Arms

Radius arms are commonly found in vehicles running live axle suspensions systems – examples include the Y61 Patrols, Land Rover’s Defender and some Landcruisers – and while the radius arm arrangement is good for on-road performance, link or bush binding (an inherent problem with this arrangement) can limit wheel articulation off-road. In extreme situations, you can have one wheel pushing up and the opposing wheel drooping, which can cause the links to twist the axle housing along its axis, much like a torsion bar.

According to Superior Engineering, their patented SuperFlex Arms are a blend of two different styles of radius arm, each complimenting the angles of deflection required for controlled flex. The key being to change the planes of deflection to allow more travel and reduce bush binding. The system also transmits complimentary torque back into the chassis to reduce the sway that multi-link or pivoting/wristed radius arm setups produce, and Superior Engineering says it can do it all while maintaining on-road driveability.

The SuperFlex Arm system includes a change in bush type and orientation that provides more control over how the bushes deform. Adapter plates change the bush position which provides a larger range of allowable flex before binding, while still providing adequate ‘feel’ back into the chassis. The arms themselves are designed with accurate caster correction built in, alleviating any loads on the bushes, further increasing suspension life and aiding correct steering geometry.

Superior Engineering’s Hybrid Radius arms have been designed to combine the benefits of the Superflex Arm technology and the improved high-speed handling of a drop-box style mounting on Nissan Patrols. Superior Engineering says that this system can soak up the bumps and keep the wheels planted without sacrificing the articulation that the SuperFlex arms provide. A newly developed drop box mounting for GU and GQ Patrols – that is nearly 20 percent lower in profile than any other on the market – mounts the specially designed Radius arms. In this application, the Radius arms are available in standard or SuperFlex configurations and are substantially longer than a factory arm, further increasing articulation and improving handling. The rear arm bushing has been upgraded to a radial type bush rather than the failure prone pin type mount.

All SuperFlex Arms are supplied ready to bolt on, with OE style rubber bushes pressed in, the necessary adapter plates, all the required bolts and of course fitting instructions. Full NCOP testing paperwork is available for easy engineering approval in most states. All Radius arms are Australian made and manufactured from 700-grade steel (Bisalloy) that is CNC machined for precise caster location and powder coated for maximum durability and a high-quality finish.

If SuperFlex isn’t enough, then you may want to check out Superior Engineering’s recently released HYPERFLEX Radius Arm system. HYPERFLEX is a combination of 2 arms featuring the SuperFlex design as well as Hybrid drop boxes and adapter brackets to help change the bush orientation on both sides of the differential. The arms are pre-drilled for the fitment of either a standard swaybar or the patented ‘Superflex Swaybar’ that improve flex while maintaining on-road performance. Raised shock towers allowing the fitment of extra-long travel shocks are also available to compliment the HYPERFLEX Radius Arms.

Superior Engineering Radius, SuperFlex and Hybrid Arms are available to suit suspension lifts ranging from 0 to 6+ inches and to fit various Nissan, Toyota and Land Rover models.

For more information, you can call Superior Engineering on (07)5433 1411 or visit

The above Superior Engineering products are protected by patent numbers 2012203220 and 2008202797. 

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