Smooth operator on the rough
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Mercedes-Benz launched the new generation of Unimogs at its Stuttgart base last week. The three-model range represents a change in philosophy as its priorities move from ultimate off-road ability to greater flexibility with increased refinement
• by Colin Barnett The Unimog has earned the status of a classic in its field as it enters its 50th year with 320,000 sales behind it and the introduction of a fourth generation. Starring features of the range are a new cab, state-ofthe-art drivelines and improved operator comfort.
The range Two of the three new models were unveiled at the launch: the U300 and U400. These will go on sale on the Continent in April and will gradually replace the current L11400 to U1600 medium-duty Unimogs. -UK sales will begin later in the year. The larger U500, the replacement for the heavy-duty U2100 to U2450 models, will be unveiled at the IAA Show in Frankfurt in the autumn with sales starting in April 2001.
Cab comfort The most obvious feature of the latest Unimog is the new cab. Built from a carbon-fibre composite material, the cab features a shorter nose and has a windscreen twice the size of the previous model.
While its appearance is more purposeful than beautiful, it has more interior space and is no heavier than the previous steel cab. It is also corrosion proof. The interior remains a functional workplace but is now closer in ambience to a modern van than the previous tractorlike surroundings.
The new cab's party piece is the VarioPilot option. With the removal of the dash trim panel and the operation of a couple of failsafe levers, the entire driving position—steering, pedals and instruments—can be transferred from one side to the other in less than 30 seconds. Another cabin option is a special door moulding on the passenger side which allows a machine operator to work sitting at 90' while the driver continues to drive.
The interior is well trimmed with cloth facings, integral three-point seat-belts and head restraints on all seats. Air conditioning is standard and there are numerous storage areas.
Engines
The new generation Unimog is powered by a range of engines consisting of four-cylinder units of 148 and 174hp and sixes of 228 and 275hp, all meeting the impending Euro-3 emissions regulations. Engines are now positioned behind the front axle line and drive through a short shaft to the mid mounted transmission.
Transmission
As standard the transmission, now with permanent four-wheel drive, is a version of the Telligent electro-pneumatic automated system previously used on the Actros. Although the clutch pedal is retained, the driver pre-selects whole or half gears on a stubby fore-and-aft lever.
Electronic monitoring pre
vents potential out-of-parameter gear changes being made. A variety of transfer box options can provide up to 24 gears in each direction, with ratios suitable for hauling 1,000 tonnes of railway rolling stock or for keeping up with 50mph traffic.
Central and rear differentials are lockable as standard, with the option available on the front axle. The Unimog has ABSequipped discs front and rear, despite the tipper world's resistance to disc brakes. The previous suspension layout of independent portal axles with long-travel coil springs is retained, but is attached to an all-new chassis.
Designed using computerised methods not dreamed of in 1951, the flat-top frame incorporates straight main rails with bolted, tubular cross-members.
Carefully laid out attachment of chassis components ensures that space is reserved for stabiliser legs and the like.
Productivity
While the Unimog can be used as a simple load carrier, its true purpose is as a platform for specialist machinery, and signifi cant improvements have accounted for this, Machinery can be carried on any of four mounting areas at the front, rear and sides: while bodies can be attached directly to the chassis or to an extra subframe.
Equipment is powered directly from a central source via quick release couplings instead of PTO-driven hydraulics. The sophisticated hydraulic system controls eight outlets from a single joystick next to the gear lever, Two hydraulic circuits can be fed at 25 and 50Iit/min or combined to give 75Iit/min for hungry machinery up to a rat ing of 100kW. The desired flow rate is
11500 dialled in
and, within limits, will be maintrained regardless of engine speed.
Pricing details have not been released, other than to say that "the cost-benefit ratio will be significantly improved", which we understand to mean that prices will increase, but will be more than compensated for by improved specifications.