When it comes to tractor units and Mercedes-Benz trucks, most people will immediately think of the Actros range but that’s not necessarily the only option available to potential operators. The product team at Mercedes-Benz obviously recognise not all tractor semi-trailer combinations spend all their time on the motorway network but for certain operations require tractor units to go off-road. When it comes to off-road operations many trucks are of the multi-wheeler variety but in some circumstances an articulated combination makes more sense.
This where the Arocs comes into it own, boasting an uprated driveline and suspension system helping to differentiate itself from the more familiar Actros range.
The Arcos range is extremely diverse covering all types of major product groups, starting with the rigid range which has two, three and four axled vehicles. The 18 tonners are available as 4x2’s and 4x4’s, the 26 tonners available as 6x2, 6x4 and 6x6 axle combination. Finally the four axle rigids can be specified as an 8x2 and also 8x4, with all the multi-wheelers having either steel or air suspension.
Of course, in this feature we are looking at the Arocs tractor unit and the line-up, in many ways follows the rigid range with the same mixture of two and three axled units, with the same axle combinations of 4x2, 4x4, 6x2 and 6x4 but this range also adds on an all wheel driven three axle 6x6 unit on steel suspension. Special Types on both rigids and tractor units also exist.
The Arocs is available with all four of the Mercedes-Benz engine line-up, from the 7.7 litre OM936 at 270 bhp to the 15.5 litre OM437 rated at 620 bhp. Our road test unit was fitted with the ‘middle’ six cylinder 12.8 litre OM471 at its powerful 530bhp setting developed at a very low 1600rpm and torque levels of 2600 Nm again developed at a low 1100 rpm and continues to hold most of this across 500 rpm to 1600rpm.
Behind the engine is the third generation of the Mercedes-Benz Powershift automated gearbox featuring 12 speeds, this also features six-application specific variants with selectable driving modes including rocking mode and fast reverse. The crawl function allows for easy moving off when the hill holder is active especially useful when pulling away on hills and inclines.
Our vehicle had the 3450mm wheelbase with a 750mm overhang, the 25 tonne gross vehicle weight is made up of a 7.5 tonne front axle, 11.5 tonne ‘mid-axle’ and 7.5 tonne on the third axle which unusually is a tag, all of the axles feature 315/70 R22.5 tyres. And can be specified with either steel or air suspension.
Braking starts with the engine braking system as normal but the Arocs also features an optionally high performance engine brake which has a three-stage, wear-free auxiliary brake offering up to 480 kW of brake power with the main benefits of potential reduction wear on the service brake while enhancing safety and control of the vehicle. Chassis space is at a premium on a 6x2 tractor unit so the fuel tank is a relatively small 320 litres supplemented by a 60 litre AdBlue tank.
Mercedes-Benz has a comprehensive range of cabs available on the Arocs, and they are made up of the familiar Short, Medium and Long cabs denoted by the letters ‘S’ , ‘M’ and ‘L’.
This is further supplemented by three cab types ‘ ClassicSpace’, ‘StreamSpace’ and the largest ‘BigSpace’,all resulting in nine cab variants and two cab widths of 2300mm and 2500mm.
On the exterior the cab has LED daytime running lights along with LED tail lights, there’s an air deflectors supplemented with side defectors along with protective metal grilles for the headlights which feature automatic main and dipped beam and cornering lights.
Our test vehicle featured the L cab BigSpace with a 2500mm exterior width and its 2300mm cab length with a fully flat level floor allowing for a 1990mmm headroom. Inside the cab, there are electric windows and roof hatch and of course one of the unique features, when it was launched, is MirrorCam and this system has two LCD screens on the ‘A’ pillars negating the use of rear view mirrors helping with very noticeable reduction in cab noise.
Inside, the drivers velour seat is suspended as well as ventilated which is the same for the passenger seat, behind the seats the bunks have drawers underneath and there are storage compartments on either side of the cab which can be accessed from the exterior or interior.
The Arocs sits higher on the road than the conventional Actros road going tractor unit, which combined with the flat floor results in a five step climb up to the cab. Finding a comfortable driving position is a doddle with the fully air suspended driver seat and in front is the fully interactive multimedia cockpit twin LCD panels which are nearly all controllable via the multifunction steering wheel, touch screen or buttons. In the centre console sits the heating and ventilation controls for the fully air conditioned system and there’s the standard set of switches for ancillary equipment control.
Once started and ‘D’ is selected on the steering wheel stalk, the 530 bhp engine is very quietly awoken, the latest generation Powershift 3 gearbox proves that Mercedes-Benz has learnt a lot over the years, as the gear changes are slick. Its noticeable that you are sitting higher than a standard tractor unit which offers a great view of the area around you and MirrorCam ( which has just been updated) helps with any blind spots especially in the sunny weather, in cab noise is also reduced. The ‘tag’ axle 6x2 matched with the loaded tri-axle trailer offers a good level of handling and as with all new trucks, controlling the speed is simply a case of using your hands rather than your feet.
Off road tractor units are often seen as niche vehicles with multiwheelers the norm on a construction sites but the very capable Arocs potentially makes a lot of sense if rigids don’t suit your requirements.