PORTAL AXLES VS COIL CONVERSION FOR A 79 SERIES: WHAT'S THE DIFFERENCE?

If you own a 79 Series LandCruiser, it doesn't take long before the modification rabbit hole starts. Bigger tyres, better suspension, more clearance… and eventually someone mentions either portal axles or a coil conversion.

This Sandy Taupe V8 79 takes things to the extreme with portal axles — serious clearance and a serious stance.

They're both serious upgrades that completely change how the vehicle performs off-road. But they do very different things, and they suit different types of builds.

Here's a breakdown of the two most common high-end options for the 79 Series - Portal Axles vs Coil Conversion. With key specs, what they actually change on the vehicle, and which one makes sense depending on how you use your Cruiser.

WHAT ARE PORTAL AXLES?

Portal axles are a complete axle upgrade that raises the axle housing above the centreline of the wheel.

Instead of the axle sitting directly through the wheel hub like a normal differential, portal gearboxes sit at each wheel, effectively lifting the drivetrain without needing huge suspension lifts.

Portal axles lift the diff housing well above the centreline of the wheel — huge ground clearance without massive suspension lift.

The Marks 4WD portal kit for the 70 Series is the most well-known system in Australia.

What makes portals unique is that they lift the entire axle assembly, not just the body or suspension. That means the differential itself sits higher off the ground — which is why portal-equipped vehicles can drive over obstacles that would normally smash a diff housing.

Some of the key numbers behind the Marks portal kit:

• 150mm (6 inches) of lift under the axle.

• Engineered for 35-inch tyres.

• 4,000kg GVM upgrade.

• 16% gear reduction at the hubs.

• Diff clearance equivalent to running roughly 43-inch tyres on a standard LandCruiser.

That gear reduction is also important. Because the reduction happens at the hubs, it reduces strain on the transmission, diffs, and CV joints, which can actually help protect the driveline when running larger tyres.

From the side you can really see the lift portals deliver—this 79 sits tall even before adding suspension.

Portal hubs do require servicing every 10,000km, as they contain additional gears and oil. They are an incredible piece of engineering, but they're also a more specialised setup typically aimed at serious off-road builds.

WHAT IS A COIL CONVERSION?

A coil conversion replaces the factory leaf springs in the rear of the 79 Series with a coil spring and link suspension system. The Superior Engineering coil conversion is one of the most well-known options for the 70 Series platform.

Instead of leaf springs controlling the rear axle, the system uses coil springs, trailing arms, a panhard rod, and performance shocks. This dramatically improves how the rear suspension works. Where leaf springs are strong but relatively stiff, a properly engineered coil setup allows the axle to move more freely. That means better ride comfort, improved traction, and significantly more wheel articulation off-road.

Superior’s coil conversion replaces the factory leaf springs with a coil setup for improved ride and articulation.

Superior's largest kit for the 79 Series is designed around a 5-inch suspension lift and 37-inch tyres. They also offer a slightly smaller setup: a 4-inch suspension lift and 35-inch tyres.

This suspension setup typically delivers around 100–125mm of suspension lift over factory height, depending on the configuration. The kit is also available with a 4,000kg GVM upgrade, while the braked towing capacity remains at 3,500kg.

Warnie and Brent fitting a Superior coil conversion — transforming the way a 79 Series rides and handles off-road.

PORTAL AXLES VS COIL CONVERSION: SPEC COMPARISON

Sometimes the easiest way to understand the difference is by looking at the numbers side by side.

Feature	Marks 4WD Portal Axles	Superior Engineering Coil Conversion
Primary Upgrade	Portal axle drivetrain system	Full suspension system
Lift Type	Under-axle clearance increase	Suspension lift
Lift Amount	150mm (6 inches) under axle	~100–125mm suspension lift
Tyre Engineering	35-inch tyres	35-inch or 37-inch tyres
GVM Upgrade	4,000kg	4,000kg
Brake Tow Capacity	3,500kg	3,500kg
Gear Reduction	16% hub reduction	No reduction
Diff Clearance	Equivalent to ~43" tyres on standard Cruiser	Standard diff clearance
Rear Diff Housing	Track-corrected housing	Track-corrected housing
Maintenance	Portal hubs serviced every 10,000km	Standard suspension servicing

WHICH ONE IS MORE COST EFFECTIVE?

Portal axles are generally the more expensive setup. They involve replacing major drivetrain components and installing portal gearboxes at each wheel, which makes them a far more complex system.

Coil conversions are still a serious modification, but they tend to be more cost-effective for the improvement in ride quality and off-road performance that most people are looking for. For touring builds, work vehicles, or heavily loaded 79 Series setups, the coil conversion often delivers the biggest real-world improvement in how the vehicle drives.

Under the back of a coil converted 79 — Superior’s heavy-duty diff and suspension components doing the hard work.

MAINTENANCE AND COMPLEXITY

Another factor people don’t always think about is maintenance.

Portal axles introduce additional gearboxes at each wheel, which means:

• Additional servicing

• More mechanical complexity

They are extremely capable, but they’re also a more specialised setup. Coil conversions, on the other hand, use more traditional suspension components that are easier to service and maintain.

WHICH ONE DO WE INSTALL MORE OF?

At BAW, we install far more coil conversions than portal axles. Portal axles are incredible for builds focused on extreme off-road performance, especially rock crawling where maximum diff clearance makes a huge difference.

But most 79 Series owners are building vehicles for touring, work, towing, and general off-road driving. For those types of builds, a coil conversion usually makes the vehicle far more comfortable, capable, and versatile overall.

Merlot 79 showing the coil conversion setup that replaces the factory leaf springs.

THINKING ABOUT PORTALS OR A COIL CONVERSION?

If you're trying to decide between Marks 4WD portal axles or a Superior Engineering coil conversion for your 79 Series, the best option depends on how the vehicle will actually be used.

Portal axles are incredible for maximum clearance and technical terrain. Coil conversions are usually the better choice for touring builds, heavy setups, and improving how the vehicle drives every day.

If you're weighing up the options, feel free to get in touch with the BAW team and we can walk you through what will actually suit your build.