OKA 6x6 2022 Review

As a longstanding off-road vehicle owner and avid adventurer, Steve Knowles knows a lot about 4WDs, and what he needs in the outback is something tough, reliable, with a high degree of capability and lots of cargo capacity.

He quickly realised that these ingredients couldn’t be found on a shelf. As a West Australian, he was also acutely aware of a homegrown off-road machine selected since the late 1980s by mining and agricultural companies, specialist services including fire brigades and the military, and a few private tour operators.

OKA was a coveted, small-volume builder of a flat-panelled 4WD light truck and while its early models were considered a work-in-progress because of the need to problem solve to answer some criticisms, improvement abounded in later models.

History in the making

Steve’s particular example is number 391 (it started life in the mid-1990s as a 4x4 bus) and those surviving - estimated at around 80 per cent - are mainly in Australia, although a few are scattered around the globe.

The marque’s initial build problems were nothing compared with OKA’s corporate history that soared and plummeted with the trajectory and speed of a competition squash ball.

That abruptly ended in 2017 with new owner Dean Robinson who brought a raft of changes to the business and honed the vehicle with new components and design features.

One thing he didn’t change was the go-anywhere ruggedness, simplicity and load-carrying attributes that the original OKA vehicles were famous for.

Armed with confidence in OKA, Steve went to Dean and together they penned a larger motorhome version, kitted with a six-wheel drive layout for absolute off-roadability, and features including adjustable air suspension and an on-the-run central air pressure system for the tyres. That’s along with sleeping and eating for four in comfort, and other modern ‘essentials’ required when far from civilisation for days or weeks on end.

“It took five years to get here, with much of that getting the vehicle right while unavoidable delays such as COVID hampered delivery,” Steve explained.

“My wife and I have now done more than 12,000km, mainly to the interior of Western Australia and some trips with 4WD clubs.

“It was always the plan to take it overseas, with Europe and Africa high on our agenda. But COVID and the problems in some countries - most recently Russia - have meant we’re appraising our travel plans. At the moment, the US is looking good.”

6x6 OKA first

The 6WD drivetrain is a first for OKA and company owner Dean Robinson thinks it may stay that way for a while, as he concentrates on the booming service industries, particularly fire brigades and the military.

Steve’s vehicle, with a cost so far approaching $500,000, may be one of a small band of elite machines in Australia with these world-class capabilities that evolved through careful planning and thorough engineering.

It has a country-eating range of more than 2700km thanks to its main 500-litre fuel tanks, and self-sufficient power courtesy of 800-Watt photovoltaic cells on the roof, various onboard battery packs and a 200-litre fresh water tank with filtration for recycling. The water for the gas-free motorhome is heated by a 600-Watt unit behind the rear seats.

It uses a Cummins 5.9-litre six-cylinder turbocharged and after-cooled diesel with 135kW/665Nm - not the standard four-cylinder Cummins in the OKAs now being produced in the Perth suburb of O’Connor – and former truckie Steve wanted a manual transmission instead of the six-speed automatic so it has an 11-speed Eaton Road Ranger.

The package goes through a heavy-duty Vickers transfer case, and culminates in a set of ratios that in the lower end starts at 26:1 and then gears down to end up at 240:1. As Steve explains: “At 700rpm, which is idle, in low-low gear, it takes 15 seconds for one revolution of the wheel.”

Chassis specs also include ventilated disc brakes on all wheels, high-profile 20-inch Continental MPT81 off-road tyres, and a clever six-rod rear suspension system that shares similarities with the Kenworth drive.

Impressive detail

At every step of the build, lessons learnt from previous OKA builds were taken on board and then expanded, while taking into consideration the specific role of Steve’s machine and its obvious size and weight.

And those specs are impressive. It has a GVM of 11.5 tonnes and is 8.3m long, compared with the standard model at 6.0m. Cab width remains at 1.9m so it can comfortably fit the width of most off-road tracks.

It’s also higher than the standard-spec 2.5m because of a roofline that centres on a lift-up section to provide full standing room inside when camping. The pop-top raises and lowers on air rams, with the same system employed in the fold-down stairs.

Also part of its off-road package is a roo bar and LED spot lights, a roof rack with side ladders, scrub bars to protect the side awning and a rear wheel carrier for two spare tyres. Ground clearance is an impressive 330mm under the diff and 500mm under the fuel tanks.

Comfy camping

Step up into the white painted, steel motorhome body and there are storage areas beneath the two double-size beds at each end, along with an inverter cooktop within a drawer in the kitchen and plenty of storage areas throughout the camper unit.

Aside from the dual-cab-style driver and passenger seats up front, there’s seating in the motorhome with a table that slides out to form a dinette. The kitchen also comes with a sink, microwave, air-fryer, food processor, and a couple of fridges.

Windows on all sides allow for plenty of natural light and ventilation, and there’s LED lighting for night-time. The combination shower and toilet even boasts an in-built recirculating system for continuous showers out bush.

Summing up

This one-off OKA 6WD expedition vehicle is certainly distinctive, and kitted out with the best of gear and the space to comfortably house four people, can lay claim to one of the world’s ultimate tourers.

How much does the custom OKA 6x6 motorhome cost?

Price: $500,000 (approx.)
Base vehicle: 1996 OKA 4x4 bus #391
Engine: 135kW/665Nm 5.9-litre turbo-diesel six-cylinder
Transmission: 11-speed manual
Fuel tank: 500L
Travel length: 8300mm
Travel width: 2050mm
Body width: 1900mm
Travel height: 2950mm
GVM: 11,500kg
Body: Four berth, steel
Chassis: Steel ladder chassis
Suspension: Adjustable airbags, custom six rod rear
Brakes: Ventilated discs
Tyres: 20-inch Continental MPT81 off-road
Water: 200L combined
Battery: 200Ah lithium plus AGM auxiliary
Hot water: 600W
Cooking: Induction cooker, air fryer, microwave
Fridge:  2 x compressor
Shower: Combined internal shower/ toilet
Lighting: LED throughout
More info: OKA All-Terrain Vehicles