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Mercedes has finally unveiled the Arocs range, which looks set to make a significant impact in the UK construction truck market Words: David Wilcox MERCEDES-BENZ COULD at last be poised to become a significant player in the UK's heavy construction truck market, thanks to a huge line-up of new Arocs construction vehicles ranging from 18-tonners to multiwheelers and tractor units.
Unveiling Arocs in Germany last week, the just-promoted head of Mercedes-Benz Trucks Stefan Buchner explained why the company developed a complete range of construction trucks rather than merely adapting haulage chassis. Noting an increasing degree of specialisation, Buchner said: "One size fits all is a thing of the past."
That explains why Arocs vehicles have their own chassis, which use C-section cross-members rather than the tubular ones of the Actros and Antos chassis. This is designed to give a little more flex to Arocs frames.
There are seven cab types, five of which are 2.3m wide but with different lengths and heights, each with a choice of two mounting heights giving an engine tunnel height of either 320mm or 170mm The other two cabs are flatfloored, 2.5m-wide sleepers. Better angles of approach and steel bumper corner-sections mark these out as construction vehicle cabs.
According to their gross weight, Arocs variants are powered by one of four engines, all six-cylinder, Euro-6 units: 7.7-, 10.7-, 12.8and a new 15.6-litre engine. Power ratings span from 235hp to 617hp. Mercedes has taken the bold move of making its automated manual PowerShift 3 transmission standard in every model, with eight-speed versions for lighter chassis and 12-speed or even 16-speed boxes for heavy models. They include crawl and rocking mode. Nineor 16-speed manual gearboxes are demoted to the options list.
New front axles are almost straight instead of cranked, increasing ground clearance. For the same reason, off-road models have hub-reduction drive-axles, whereas road-going Arocs units have single-reduction axles. Brakes can be drums all round, all disc or a combination of both, depending on the model. The standard suspension set-up for on-road Arocs is steel at the front and air at the back; offroad models have parabolic steel-leaf suspension at the rear with two, three or four leaves according to axle capacity.
Far tighter option Mercedes is offering two-, threeand four-axle configurations, from 4x2 18-tonners to 8x8. Four-axle vehicles are available with electro-hydraulic steering for axles one and two, rather than mechanical linkages. For operators only occasionally needing extra traction, there is a far lighter, switchable hydrodynamic front axle option, using hydraulic motors in the front wheel hubs, driven by the PTO.
As well as the usual 8x4 layout, there is a mixer chassis with one front and three rear axles (axles two and three driven), similar to Volvo's Tridem. There is an 8x2, but weight-hungry mixer operators can also cut kilos by choosing the Loader 8x4 mixer chassis. This has single tyres instead of twins on the drive axles. These 385/65 R22.5 tyres normally have an axle load rating of nine tonnes, but it is claimed that these Continental HSC1 tyres are specially produced for Mercedes and carry a 9.5-tonne rating. Single tyres give a wider track, improving stability, and Mercedes reckons reduced traction should not be a problem for most mixers. This, and a host of other weight-saving features, allows the 8x4 Loader to carry 8.5m3 instead of the usual 8.0m3 of concrete, claims Mercedes.
Precise weight data is not yet available for the Arocs range, but the huge number of chassis, cab and engine permutations suggests operators should be able to save weight where it suits them. Euro-6 EGR and exhaust after-treatment inevi- tably add kilos, but the new 0M470 10.7- litre engine is 141kg lighter than the 0M471 12.8-litre engine, opening up a real weight-saving opportunity. With power and torque ratings of up to 422hp and 2,100Nm, this 10.7-litre engine looks like a wise choice for the 8x4 Arocs. First impressions suggest they have potential to challenge the Scania, Volvo and Daf triumvirate that dominates the UK 8x4 construction chassis sector. •