Mack Super-Liner 70-inch sleeper 2023 Review

The radio crackled to life as our Mack Super-Liner rumbled past the oncoming cattle truck, a road train triple. Both rigs billowed dust as they edged onto the dirt shoulder, before squeezing past on the thin ribbon of bitumen. “Nice truck ya got there, mate!”

Out here in far western Queensland, where the laser-flat landscape stretches to the horizon, passing another driver is a welcome diversion, and a friendly wave is often followed by a quick chat over the airwaves.

That’s not unusual. But what was, in this case, was that it was one of many compliments coming our way from drivers of a certain ‘other’ brand of heavy hauler, whose nine-ohs, C5s, and T659s dominate this landscape and usually attract an almost religious devotion.

But I couldn’t disagree: with its gloss grey and black paint, black bullbar festooned with LED driving lights, chrome exhaust stacks, and matt-black tanks and wheels, our Mack Super-Liner was indeed a head-turning bit of gear.

However, what these drivers couldn’t appreciate was that this truck was also sporting the very first, and thus far only, example of the manufacturer’s new 70-inch sleeper.

First revealed at the 2023 Brisbane Truck Show, this prototype, fully integrated 70-inch sleeper builds on the existing 60-inch unit. It adds even more space but it’s also a true ‘stand up and walk through’ sleeper, with more comfort for those who spend long periods on the road.

It came about after Mack saw an opportunity in the NHVR’s 2021 concession for B-doubles on road train routes, where the maximum permissible length increased from 26m to 27m. It gives operators a lot more flexibility, so Mack developed a cab with even roomier living quarters, and this 70-inch sleeper was born.

It will be available from late 2024 for both the Super-Liner and its off-road-spec’d sibling, Titan, but not the new Anthem.

trucksales was invited to drive this ‘Big Bunk’ Super-Liner and we didn’t need to be asked twice. Starting from Mount Isa, we traced an 1100km loop south to Boulia then west to Winton, overnighting in the truck before returning to the Isa via Cloncurry the next day.

Running at around 90 tonnes, this Class 2 road train was hooked up to an AB triple of curtainsiders, measuring in at 44m in length.

Under the bonnet was Mack’s MP10 in its flagship 685hp/2300ft-lb (515kW/3180Nm) rating, which marks it apart as Australia’s most powerful conventional truck. And while a 90-tonne load wasn’t stretching a truck that can handle over 200, the Outback conditions provided a solid test nonetheless.

Journalists are generally a circumspect bunch but I feel no shame in saying that, for me, this trip was Christmas on wheels. While I hold an MC licence, I’d never driven a road train, and ticking that box in a truck like this, out here, well – the job just doesn’t get any better.

My ‘chaperone’ was Volvo Group Australia media boss Matt Wood. ‘Woody’, who is no stranger to driving big rigs, kindly guided the truck out of town and past the surrounding ranges, before pulling over to swap seats.

I’d be lying if I didn’t say I was a little daunted at the prospect of handling 90 tonnes on a narrow strip of tar, especially when a small steering input at the pointy end can result in a significant flick of the rearmost trailer, but I settled in soon enough.

The fast acclimatisation was down to the easy-driving nature of the Super-Liner itself, and its automated manual transmission. In heavy haulage land, some might say the only tool for the job requires a Roadranger. But when the Mack Super-Liner was last overhauled in 2021, when the new Mack Anthem arrived on the scene, the platform’s new wiring architecture spelled the end of the non-synchro manual.

Today the Super-Liner is only available with an AMT: the standard 12-speed mDrive, or the optional 13-speed mDrive HD (as fitted to our test truck) or 14-speed mDrive XHD. And when these fuss-free AMTs are paired with the low-revving, flat torque curve of the MP10, it’s a recipe for efficient heavy haulage ability.

With standard, economy, performance, and heavy-duty modes, the mDrive makes light work of driving a seriously big rig, and while manual shifting is simply a touch of a button away, for the most part I let it do its own thing.

Also smoothing progress was Mack’s PowerLeash auxiliary brake. With discs all round this rig pulls up well anyway, but out here the three-stage PowerLeash is your go-to for braking most of the time. Simply flick the right-hand stalk down once for exhaust brakes, again for engine brakes, and then again for both. Bump it down again to downshift, the higher revs further slowing the show.

The roads out here are often little more than potholed goat tracks, but the Super-Liner’s eight-bag rear air suspension irons things out nicely. The steering too instills confidence – the truck tracks straight and true and handles dropping off onto the shoulder without too much fuss. It feels nice and direct, despite the physics of the load and combination.

Vision is good and driver comfort is excellent. The multifunction steering wheel is adjustable for tilt and reach and the ISRI air suspension seat is a ripper – love that lumbar support!

All the various controls are logically placed but there are only dash-mounted buttons for the AMT. Flicking through the trip data on the central display is via the controls on top of the PowerLeash, and in general all the instrumentation is clear and easy to read.

I would have appreciated a large tray for my log book and other odds and ends, and a dedicated spot to store my phone. Mack tells us the ashtray will soon make way for the latter, which will coincide with the arrival of Apple CarPlay.

The unwritten rules are simple: anything smaller than a road train should move well off the road to let the big guys pass. While we didn’t tackle any dirt, most of the roads we took were only a car-width wide. So when two oncoming road trains meet, things can get interesting…

While it might look like a high-stakes game of ‘chicken’, the deal is for both rigs to stick to the centre of the road until the last moment, when each moves onto the shoulder to squeeze past. You move over late to minimise the billowing dust for the oncoming driver.

On one occasion we were crawling up a gradient when an unloaded triple cattle train came flying downhill around the bend. I got the prime mover off the road soon enough, but it took an age for the last trailer to follow suit. It was fine, but it’s easy to see how things can go wrong out here…

Speaking of safety, the Super-Liner comes standard with the Bendix Wingman system, with autonomous emergency braking, lane departure and blind-spot warning, plus adaptive cruise control. Add in staples like stability control and ABS, and it’s a solid suite of features, although we noted our truck didn’t have any airbags.

Mack’s MP10 churns out the grunt. Based on Volvo’s D16G, it’s a potent tool for hauling major loads. Mack says sales for road train applications have been a “slow burn” since the Super-Liner was overhauled, but word is starting to get out – of its reliability, strength, and fuel economy.

Mack says some road train operators are reporting significant time and fuel savings with this truck, as its powerful engine can hold top gear at the speed limit even when driving into a stiff sou-westerly across the Barkly Tablelands, where other trucks might need to gear down.

We rumbled across the flat landscape in (overdrive) 12th at 90km/h with the tacho on 1300rpm. In fact, the tacho rarely strayed below 1200rpm or above 1400rpm, save for some of the climbs through the ranges around Mount Isa. The growl of the engine is there but it’s muted – holding a conversation is easy.

But the sheer inertia of these rigs is incredible. Back off and the truck rolls on for ages, barely dropping speed. And once you’ve braked, it takes a bit to reach highway speed again. We were running a highway axle ratio of 3.7:1, lending itself to sealed highway work.

After a bite at Boulia we headed west for Winton, past Min Min and Middleton, while skirting some light showers. Reaching Winton around 5pm, we dropped the trailers and drove bobtail into the main drag, parking up near the historic Tattersalls Hotel, a long-time haunt of road-train truckies. Then, after a cleansing ale and a succulent steak, Woody headed to a nearby hotel and I headed back to the truck to grab some sleep.

While the metalwork and superstructure for this prototype were imported from the ’States, when the new cab enters production in late 2024 it will be fully produced and assembled at Mack’s Wacol facility in Brisbane.

So, what’s it like? In a word, big! It has a flat floor with no raised transmission tunnel, so you can easily get up from the driver’s seat, turn around, and walk on in. There’s a huge 2.1m ceiling height just before the bunk and enough space between the hanging wardrobe on one side, and the microwave, TV, and upright fridge on the other, to get changed easily.

Storage is everywhere. There are compartments over the dash and neat wraparound shelving for odds and ends, masses of storage in the hanging wardrobe and the cupboard below, a pull-out drawer beneath the TV, and three huge lockers over the bunk (which can be replaced by a second bunk, if required).

The king single innerspring mattress is super comfy and generously proportioned (200cm by 100cm). Neat features include opening windows at either end of the bunk for crossflow ventilation, a pull-out table beneath the hanging wardrobe, and quality block-out curtains that partition the sleeper from the rest of the cab.

It was a warm night in Winton, about 24 degrees, so I simply ran the Icepack for 10 minutes to dissipate the heat in the cab, before opening the sleeper windows. As well as offering heating and cooling, the Icepack console includes USB outlets to charge your phone, as well as a stereo and cab lighting controls.

At 6ft 2in and 90kg, I’m no featherweight, but I really appreciated this sleeper’s space and practicality. I’m also a light sleeper, so it’s testament to this cab’s all-round comfort that I slept solidly until just before 6am, when it was time to head north-west back to Mount Isa.

When the mine at Mount Isa swung into view, we’d clocked just over 1100km over the two days, averaging 1.3 to 1.5km per litre. Not too shabby at this weight but, even so, with a 2000L fuel capacity, I was happy not to be footing the fuel bill!

This drive gave me a rare insight into the road trains that are the lifeblood of the Outback. These iconic leviathans are vital to Australia’s mining, livestock, and grain industries, among others, not to mention the many Outback communities that rely on them for just about everything.

In Mack’s 60th year in Australia, I can only wonder what the drivers of those early Mack trucks would think of this Super-Liner. Of course, they’d be gob-smacked by its power, its strength, its reliability, and its comfort.

This Mack Super-Liner breaks new ground, with a compelling blend of comfort and capability that I’m sure will see many more examples soon crisscrossing our vast nation in road train format.

Thinking back to the compliments from those passing truckies, yes, on the outside it sure is a nice-looking truck. But just wait until you take a look inside one!

Model: Mack Super-Liner
Engine: MP10 16.1-litre inline six-cylinder turbo-diesel
Power: 685hp (515kW) at 1500-1900rpm
Torque: 2300ft-lb (3180Nm) at 1000-1500rpm
Transmission: mDrive HD 13-speed AMT
Retarder: Mack PowerLeash
Front axle: Mack FXL, 7500kg capacity
Front suspension: Parabolic spring, heavy-duty
Rear axles: RTS2310A single reduction hypoid drive, 23,000kg capacity, GCW 100,000kg (max engine torque 3550Nm)
Rear suspension: Eight-bag Mack air suspension
Axle ratio: 3.70:1
Wheelbase: 6050mm
Brakes: Discs all round with EBS, ABS and traction control
Fuel capacity: 2000L (1200L RHS, 800L LHS)
AdBlue: 200L (RHS)
Tare weight: 10,400kg
GCM: 200 tonnes (more on application)
Safety: Bendix Wingman with autonomous emergency braking, adaptive cruise control, lane departure warning and blind-spot monitoring