Mercedes-Benz Unimog U5000 2009 Review - International

Mercedes-Benz Unimog U5000

What we liked
>> unstoppable feeling off road
>> wheel travel, traction
>> feelings of superiority over all other SUVs

Overall rating: 4.0/5.0
Engine/Drivetrain/Chassis: 4.5/5.0
Price, Packaging and Practicality: 4.5/5.0
Safety: 3.5/5.0
Behind the wheel: 5.0/5.0
X-factor: 4.0/5.0

Of the dozens of contenders claiming to be the world's best offroader, only one can pick the opposition, carry them on its back and still perform like one of the best rough-and-tumble machines the world has ever known.

Designed to be a workhorse from the ground up, the Mercedes-Benz Unimog has been so successful that: it has its own museum; is used by everyone from the Army to the United Nations; and has even been tweaked by crazed German tuning house, Brabus.

While it only sells in (very) low volumes in Australia, the Unimog has a more valid claim to be the world's best offroader than almost anything up to, and including, military tanks. In most European countries, after all, the Unimog is what they send out to repair the broken ones... Tanks that is...

At 6200kg for the U5000 long-wheelbase we tested, it has grown out of all proportion to the original Unimog, but it keeps all the important innovations that made it so successful -- except for the Power Take Off. Which you can still ask for anyway. And, if it could fit them onto its 4.1-metre cargo area, it could carry (legally) four fully-specced Toyota LandCruisers on its back and still walk over ditches a metre deep.

There are several key design features that make this top-end Unimog so brilliant in lumpy country and why the vehicle commands (in Europe) a close to $240,000 pricetag.

Firstly, its frame is designed to be elastic, with two massive, U-shaped beams linked by tubular cross-beams that are all designed to twist offroad and retain their stiffness onroad. The cabin (and whatever framework you want to put on the back) is fixed at three places, so you often see the cab moving at different angles to the chassis. It looks, and feels, a little odd, but it means it can walk over half-metre diagonal differences without straining the chassis at all.

Add to this the fact the U5000 doesn't have axles and wheel hubs as you might know them. Instead, it uses Portal axles, which means the differentials and axles sit much higher than the centre of the wheels, then they drop down through a series of gears to drive the wheels. Where the bottom of the diff housing is usually the most exposed component of an offroader, the bottom of the Unimog's rear diff floats almost half a metre off the ground. That means you can rest assured it will comfortably walk over anything half a metre high without grounding.

Not only are these wheel hubs frighteningly expensive compared to normal offroad systems, but the Unimog's hubs also have a reduction gear inside it, so the driveshafts can spin with a bit of lethargy, then rely on the gears inside the Portals to 'magnify' the torque right where it's needed.

That's not the Mog's only trick. The axles themselves live inside torque tubes. Here they are protected from damage while the wheels can articulate up to 30 degrees. If this sounds radical, it's exactly the same system Unimogs have been using for nearly 60 years -- so it's tried and tested technology.

Powering all of this driveline wizardry is a 4.8-litre four-cylinder turbodiesel engine with pistons the size of bread plates and only 160kW. A modest figure even alongside 'softroaders', what really counts is torque. The U5000 punches out 810Nm of torque almost from the second you turn the key.

The big four fires up quickly but you could never say it was quiet. Its noises do nothing to hide the fact that it's a heavy-duty powerplant -- even if the driver is surprisingly well insulated from its fire and brimstone. But, from just 1200rpm, the U5000 is already giving you every Newton-metre it can muster and it keeps giving it in a flat line until 1600 revs, by which time the next of the eight gears is ready and waiting.

In Europe, Unimogs are limited to 80km/h, though they happily run to 110 in unlimited countries.

Our test machine had the extreme offroad gearbox fitted -- which doles out another eight gears. If you're thinking low range, then think extreme low range, because in its heavy-duty cog, the speed spread across the eight gears runs from 1km/h in first gear to 15km/h in eighth. There aren't many places where you need to crawl along at 1km/h, admittedly, but if you're stuck on a steep descent trying to outrun a fire with eight tonnes of water on board, you'll be pleased you've got it.

You'd think all of this hardcore machinery would be difficult to work with, but it's a doddle. There are things you need to keep in mind, because it certainly doesn't stop like an AMG (even though it has four-wheel disc brakes and a two-stage engine brake), but it's actually quite comfortable.

It might be a three-step climb up to the cabin, but there's space to burn inside. There's a clutch pedal, but you can run the Unimog as a full automatic or you can change gears yourself and let the computer sort out the clutch. You just tip the stubby lever forward once to get into first gear and it eases off. Simple as that.

It's a permanent all-wheel drive, of course, so even getting going in the mud isn't difficult. In flat country, you can usually skip first and second, too. It will happily move off in third gear. And it will move off with a haste you won't expect from a machine this large.

It's incredibly strong with no load onboard, but it's more a case of being unstoppable than fast. Accompanied by the hiss of the turbocharger, you revel in being so isolated from any vibrations or harshness and keep pulling gears until you soon hit eighth. It should be isolated, too. The seats are suspended and, effectively, so is the cabin.

The astounding thing isn't how the Unimog goes, however -- it's how it rides. The massive wheels and tyres (365/80 R20 Michelins -- there are also 22.5 and 24-inch options) cushion just about any small bumps and the long-travel coil springs manage the bigger stuff. It feels like you're cruising along on a well-controlled carpet.

The deeper you throw it at rough country, the more the ride deteriorates. It's not vertical shocks that get you, though. It's still comfortable that way, but it begins to throw your head sideways as it settles down and rocks itself back up.

In the really serious country it just ends up being plain-out amazing. It will climb 45 degree slopes and descent them again, but that's not the half of it. It will do all this at its maximum weight, too.

You just dial up the locking differentials at both ends and ease the power on and it will walk its way up even rutted, seemingly impassible routes. If that's not quite enough, you can flick another switch and adjust the air pressure in all four tyres to see if that wins you more traction. If that's not going to be enough, you can safely declare the hill unconquerable.

The stranger the topography, the better the Unimog becomes. Provided the body fits the track (it's 2.7 metres high, almost two metres wide and, in LWB form, 6.6 metres long), there's a fair chance that the Unimog will follow whatever made it.

Approach even a solid concrete block of almost a metre high and you sit astonished as the Unimog touches rubber on it and begins to climb. And it keeps clawing its way up until the front tyres sit on top of the block. That's what a 44 degree approach angle can do for you.

The thing you'd normally worry about next is banging the bottom of the body or the sills onto the concrete as you roll over it.

Not with a Unimog. In first gear, the Mog walks calmly (even as you sit nervously, staring screen-first at the dirt on the other side), and plants its front tyres on the far side. No banging, no graunching and no scraping as the LWB's 35-degree ramp-over and 53-degree departure angles do their stuff.

It's even more impressive on diagonal obstacles, largely because it looks like a truck and you think it just shouldn't be able to do it. In such a case the whole body twists as you slowly walk one 80kg front wheel and tyre on top of the block. Both rear tyres stay on the ground along with the other front tyre. It's secure and safe and very, very impressive.

The Mog will happily live with deep water, too. Even a standard Unimog regards 800mm of water as a mere puddle, while our U5000 came with the wading kit to stretch its wading depth to 1200mm! And remember the innovative drivetrain layout means there's far less likelihood of snagging your underbody on unseen rocks than there would be in a conventional all-wheel drive.

The final trick is that you can order a Unimog with just about anything that can run on hydraulics, including a crane. That means if you do find another serious offroad contender in your travels, you can just pick it up and put it in the back.

Unimogs in Australia
Mercedes-Benz Australia/Pacific is the authorised importer and distributor of Unimog vehicles. They are sold from one authorised retailer, Unimog Sales Australia which is located in Bunbury Western Australia, but they have nationwide scope for sales and service activities.

Unimogs are not only fully imported; they used to be built in Australia at Mercedes' Mulgrave warehouse. In 1981, the Australian federal government decided to purchase 1295 Unimogs for the Australian military, which was the largest military purchase that decade. The first Australian-built versions were delivered a year later.

Aussie 'Mogs were built with 160 local components from 46 local suppliers.

In 1984 three Australian-built Unimogs were sent to Antarctica for snow cutting, towing, and for work as mobile power stations for Australian research scientists. (More info on Unimog can be found here [www.unimog.com.au]

Less than ten new Mogs were sold last year but numerous numbers are traded annually. Benz's Unimog dealer in WA has no less than 70 Mogs on his service books at any one time, and the business is growing -- mostly via the civilian sector.

Usage includes agriculture, mining, caravanning and even the odd one for council work.

And unlike some vehicles, there's almost no such thing as a worn out Unimog. With frames that are basically indestructible, like Boeing 747s, supertankers and Hollywood superstars, Mogs can and are constantly upgraded. They never truly get old.

The Brabus Experiment
You know you've entered the broader Benz consciousness when ultra-hardcore tuning house, Brabus, puts you on the radar. The result is the Unimog Black Edition -- the offroader for people with just too much money.

Where the normal top-end U500 Unimog sells for around 130,000 Euro in Europe, the Brabus version costs an astonishing 90,000 Euro more!

Built on the U500 chassis (a different, more-versatile platform to the traditional U5000), the Brabus uses the more-powerful 6.4-litre six-cylinder turbodiesel engine to crunch out 1120Nm of torque.

Other than that, there are a lot of trinkets, but nothing that makes it actually useful. In place of the work space you'd expect to find, there's a stylised black body kit, complete with polished stainless chequerplate and a massive chromed rollover hoop that would be unlikely to help much if the five-tonne machine defied physics (and Unimog folklore) to roll over.
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It's more of the same inside, with Formula One-style carbon fibre throughout -- as though the weight savings are important. There is also an upgraded sound system, beautifully crafted leatherwork and that's about it.

And, for all the extra money, they've made it worse. The standard U5000 is about 500 per cent more comfortable, because the short-wheelbase Brabus pitches and squats horribly on every gearshift, brake application and change in throttle opening. Without a big weight in it (or being towed behind it), it's unbearable.

So far, in two years, Benz has built three (including the prototype and our test Mog) and sold one. To an Arab Sheik. Which isn't really a surprise, is it?

Specifications: Mercedes-Benz Unimog U5000 (LWB)
Engine -- Four-cylinder, 4.8-litre turbodiesel
Power -- 160kW at 2200rpm
Torque -- 810Nm @ 1200-1800rpm
Gearbox – dual-range eight-speed computer-contolled automated manual
Wheels and tyres -- 365/80 R20 all-round
Turning circle -- 16.3m (SWB 14.5m)
Fuel capacity -- 145 litres
Dimensions (L/W/H) -- 6010/1965/2740mm
Wheelbase -- 3850mm
Track (fr/rr) -- 2336/1920mm
Approach angle -- 44 degrees
Departure angle – 53 degrees
Rampover angle -- 35 degrees (SWB 42 degrees)
Wading depth -- 800mm (1200mm optional)