For serious off-roaders, suspension upgrades are a cornerstone of performance. One upgrade that’s gaining traction is the rear end coil conversion. If you’ve heard the term but aren’t sure what it really means – or why someone would do it – this guide breaks it down.

Most utes and SUVs, especially older models, use leaf springs in the rear. Leaf springs are strong and simple, great for hauling heavy loads, but they have limitations in ride quality, axle articulation and adjustability. A rear end coil conversion replaces the leaf springs with coil springs, along with supporting components like control arms, a track bar and upgraded shocks. Essentially, it transforms the rear suspension from a rigid load-bearing system into a more flexible, performance-focused setup.

Typical components of a conversion include:

  • Coil springs and spring perches
  • Upper and lower control arms to properly locate the axle
  • A track bar to prevent lateral axle movement
  • Upgraded shocks to match the new geometry

The result is a rear suspension that rides smoother, articulates better off-road, and can be more finely tuned than traditional leaf springs.

Why do a rear end coil conversion?

  1. Improved ride quality: Leaf springs are stiff, often causing a harsh ride on-road and off-road. Coil springs provide a smoother, more compliant ride without compromising off-road capability.
  2. Better axle articulation: Greater suspension travel means wheels stay planted on uneven terrain. This translates to more traction and better off-road performance.
  3. Customisability: Coils come in a range of rates – linear or progressive – allowing you to fine-tune ride height, stiffness, and off-road response for your specific rig and use case.
  4. Modernisation and aesthetics: Older vehicles can feel dated in both ride and look. A coil conversion modernises the rear suspension, improving handling and giving your 4×4 a more contemporary stance.
  5. Compatibility with Larger tyres and lift kits: Coil setups allow easier installation of larger tires and higher lifts while maintaining proper suspension geometry and driveline angles.
  6. Better for off-road-focused builds: For rock crawling or trail rigs, coils outperform leaf springs in flexibility, making them the preferred choice for extreme articulation.
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Important considerations

While the benefits are clear, there are a few key points every 4×4 owner should know before converting:

  • Types of coil conversions: Some are bolt-on kits, others require custom fabrication. Bolt-on kits are simpler but can be limited in articulation; custom setups allow more freedom but increase cost and labor.
  • Impact on driveline angles: Lifting the rear with coils changes pinion angles and driveshaft lengths. Ignoring this can lead to premature wear or vibration.
  • Weight capacity: Leaf springs excel at carrying heavy loads. Coils often reduce load capacity.
  • Shock and bump stop upgrades: Coils require different shocks and sometimes longer or adjustable bump stops to prevent coil bind and maximise travel.
  • Cost and labor: Kits typically range from $1000 to more than $3000, with additional costs if welding, fabrication or professional installation is needed.
  • Off-road vs daily driving: Coils improve off-road comfort and flexibility but may sacrifice some load-carrying ability and simplicity compared to leaf springs.

Superior Engineering’s premium coil conversion kits

If you’re thinking about a rear coil conversion, one name that consistently comes up in the 4×4 community is Superior Engineering Landcruiser Coil Conversion Kits. Superior Engineering offers some of the most thoroughly engineered and road‑legal coil conversion solutions on the market.

Unlike budget kits, Superior’s packages are designed from the ground up with strength, compliance and real‑world off‑road performance in mind. They offer both bolt‑in and weld‑in coil conversion kits, with options that include track‑corrected chromoly diff housings, remote reservoir shocks, and heavy‑duty components suited to serious touring and overlanding.

Some standout features of Superior’s engineering approach include:

  • Street‑legal and certified compliance: Most kits are engineered and pre‑approved under relevant VSB (Vehicle Standards Bulletin) codes, meaning they can be legally fitted and registered across Australia when installed correctly.
  • 4‑Link suspension and adjustable geometry: Superior’s systems frequently use a 4‑link rear setup, improving both handling precision and articulation over simpler designs. This allows tyres to stay planted without compromising driveline angles.
  • Heavy‑duty fabrication: Many kits incorporate upgraded chromoly diff housings and robust chassis bracing that spreads suspension loads over a wider area of the frame – an important factor for durability on rough terrain.
  • Australian‑made and tested: Designed and manufactured locally, these kits are built to withstand the harsh conditions often faced by Australian 4x4ers, from corrugations to high‑speed desert driving.

Because Superior Engineering’s kits are developed as complete conversion solutions, they integrate braces, diff corrections, control arms and suspension geometry corrections into a package that can dramatically improve both on‑road manners and off‑road performance.

Superior Engineering has coil conversion kits for:

  • LC79: Weld-in and Bolt-in
  • LC76: Bolt-in
  • PX, PXII and PXIII Ranger: 2012-2020
  • BT-50: 2012-2020
  • HiLux (VIGO and REVO): excludes Wide Track models

A rear end coil conversion is a game-changer for enthusiasts looking for smoother ride quality, increased articulation and modern suspension performance. While it requires an investment of time and money – and some careful planning regarding geometry and load – it pays off for those who demand both on- and off-road capability from their 4×4.

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