Mercedes-Benz Actros 2644LS FleetStar Review

By: Gary Worrall


Mercedes-Benz is working hard to regain market share in Australia, and is looking to its venerable workhorse the Actros to lead the way, including as a single trailer prime mover, writes Gary Worrall

Mercedes-Benz Actros 2644LS FleetStar Review
Mercedes-Benz Actros 2644LS FleetStar

 

With a GCM (gross combination mass) of up to 55 tonnes, the Mercedes-Benz Actros 2644 is aimed squarely at the single trailer market, in both day cab and sleeper cab configurations.

As one of the pioneers of vehicle safety globally, and a leading voice in the safer trucks debate locally, Mercedes-Benz is able to offer its trucks with a full suite of safety systems.

This includes Telligent Stability Control, Telligent Brake System with ABS and ASR (anti-skid), Active Brake Assist, which applies full brake force in an emergency situation, and Telligent Proximity Control and Lane Assistant - a radar-controlled cruise control and camera to warn if the truck changes lanes without indicating respectively.

Although insurers have yet to come to the party with reduced premiums for operators taking these options, research from Europe shows strong evidence they do help reduce the number and severity of incidents, a message Jo Heinke, head of Mercedes-Benz Trucks in Australia, wants operators to hear.

Engine

Although well-known for its range-topping V8 variants, the Actros is also available with a proven V6 engine, and this is likely to hold the key to future sales success.

The 12-litre OM501 engine - actually an 11.9-litre unit, rounded up - is available in a selection of power outputs, although the big hope is for the 320kW (440hp) unit to win over the lucrative fleet segment in 2644 LS guise.

Transmission

The Actros 2644LS FleetStar features a Mercedes-Benz PowerShift 2 non-synchromesh automated manual 12-speed transmission.

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Cab and Controls

While a new cab design is available in Europe, Australia will stick with the current Actros cab for at least another two years, making it a familiar place for anyone who has driven one in recent times.

The basic cab shape remains the same, with a slight rearward rake to the cab, which becomes more pronounced at the level of the windscreen, while the chrome sun visor features polycarbonate 'eyebrows' above the driver and passenger seats to help manage the over-roof airflow, working in conjunction with the air scoops mounted on the A-pillars to push air away from the door windows for better vision.

The FleetStar is fitted with large, round-backed, power adjustable external mirrors which are also electrically heated to eliminate frost and fog on cold days, and are well-positioned from the driver's position offering good rear and side vision.

The only downside, and this is a common refrain surrounding the Euro-style mirror cluster, is the creation of blind spots at T-intersections, as the height and width of the cluster does intrude on sideways vision.

Given a choice between needing to look twice at a T-intersection and being able to clearly see a motorcyclist hiding near the front of the trailer, I will take the rear vision every time.

While the new truck will feature a similar 'cheese grater' grille to the Daimler-owned Freightliner Argosy, the current truck is slightly more subdued, with just three horizontal grille slats above the bumper line, which open upwards for access to the front of the engine bay to facilitate daily inspections.

The test truck was configured in 'Fuel Haul' specification, which meant a day cab only with low roof and no wind deflector, although paired with a regulation height curtain-side trailer this proved to not be an issue in terms of on-road performance.

In keeping with the multi-drop nature of fuel tankers, the Actros uses three steps for the cab entry and while it remains a skyscraper from a driving perspective, the driver is able to climb in and out comfortably.

The chassis-mounted bumper assembly includes two steps for ease of cleaning the windscreen, while the headlight assemblies are mounted above the halogen fog lights, level with the second cab step, offering better protection from stones and other road debris.

The FleetStar also has the engine air intake roof mounted above and behind the driver's door, allowing it to draw in as much clean air as possible, while the regular low-mounted exhaust is replaced with a vertical stack on the left rear of the cab.

As with the exterior, the Actros remains familiar ground, although the FleetStar gains some extra buttons and has fabric trimmed seats and the driver's Grammar air-suspended seat proved comfortable for the duration of the trip.

Though a day cab, the FleetStar is more of an extended cab with space behind the seats for bags, and while a fold-down bunk can be ordered, it is not designed for overnight sleep.

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The driving position retains the traditional wraparound console, creating a true 'cockpit' feel for the driver, which has the advantage of placing all switches and buttons within easy reach.

Also dash-mounted is the park brake controller, just to the left of the wheel, allowing for quick and easy release of the brakes, while the PowerShift 2 automated manual transmission (AMT) comes with a hill holder function for stop-start traffic.

Driven regularly, the dash layout would quickly become second nature, especially since the most-used buttons are placed closest to the driver.

The steering wheel is large, but thickly padded for comfort, with a four-spoke design offering plenty of wrist support, along with thumb buttons to control audio, telephone and cruise control functions.

Stalks on either side of the wheel take care of lights, indicators and exhaust brake functions, with a joystick-style gear selector mounted on the left-side of the driver's seat.

The cabin, even in short form, is light and airy, with plenty of room for the driver and a passenger, legroom is excellent even for taller drivers, while an inclined footrest replaces the clutch pedal for extra comfort.

Soundproofing remains excellent, while the OM 501 motor could never be accused of excessive noise even sitting right above it the engine is barely audible and there was no need for raised voices during normal conversation.

The FleetStar also comes with a rear window, to help tanker drivers negotiate crowded petrol station forecourts, so that all-round vision is good, with a front-mounted mirror also allowing the driver to park on bollards without requiring braille-reading skills.

Air-conditioning is standard, so even on a typically cold Melbourne morning, the cab is snug and can be warmed or cooled to suit the driver's preferences.

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Performance

After completing a quick walk-around to ensure all the lights were working and checking there was oil in the sump and coolant in the radiator, it was time to fire up the Actros.

With more computing power than an Apollo moonshot, the Actros is a little picky about the start procedure, requiring the ignition to be on, but it will not start until it has completed a self-diagnosis, ensuring it agrees with the driver about oil levels and checks numerous other functions hidden from the prying eyes of the driver.

With the motor gurgling away somewhere under the seats, engaging first gear requires drivers push the brake pedal to show they have control − a gentle push of the gear selector to the 'D' position, accompanied by a barely audible 'clank' under the floor.

With a clear road in front, it was time to release the park brake and give the accelerator a slight prod, which engages the clutch on the non-synchromesh 12-speed transmission and supplies power to the bogie drive.

The PowerShift 2 transmission provides smooth upshifts, with computers comparing engine revs with road speed to not only select the next gear, but also when to make the change.

The driver can maintain steady throttle pressure for continued acceleration, the management systems automatically cuts power for a fraction of a second to prevent over-revs

Although it does not skip gears in automatic mode, the transmission will make 'full' gear changes, rather than splitting gears, while, in manual mode, the driver can skip gears depending on road speed and engine revs.

This is an important point to make. While the driver is no longer required to press the clutch pedal or match the engine speed to the transmission, the PowerShift 2 will only make shifts that are possible within the limits of mechanical harmonisation.

That means drivers cannot pull the truck back into fourth gear at 80km/h, as the computer will see that is likely to cause significant damage and reuse to make the change, even in manual mode.

The worst case situation is a driver engages manual mode and forgets to change gears, thinking they are still in automatic mode, however the engine rev limiter will step in to cut revs if needed.

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Similarly, if drivers are approaching a steep descent, posted 'Trucks Must Use Low Gear', they must prepare for the descent just as they would in a three-pedal truck, selecting an appropriate gear before driving down the hill.

In the case of the Actros, this can be achieved automatically, by dropping the cruise control down to the desired speed, for example 40km/h, the computers will manage braking and gear shifting to maintain the set speed.

This is where the AMT offers an advantage over the traditional manual drivelines, as the computers can monitor all systems on the truck simultaneously and make adjustments as needed, rather than the driver needing to watch four different gauges and the road.

The FleetStar is fitted with a Voith retarder, which combines with the all-wheel disc brakes and the transmission to provide excellent braking power in all situations.

With cruise control the front-mounted radar scans the road ahead for slow traffic, adjusting the road speed to prevent rear-end collisions, with the radar range driver-adjustable to allow for variable traffic conditions.

Having used this equipment in a variety of trucks and passenger cars, it remains a source of wonderment that a 40-tonne truck and trailer can detect a slow vehicle, reduce speed and maintain the gap until such time as the other vehicle speeds up, turns off or the truck changes lanes, at which point the engine computer will resume the preset speed, all without driver intervention.

With 320kW and 2,100Nm, the FleetStar has more than enough grunt to handle single trailer applications, although unlikely to win uphill drag races it has plenty of usable power, with peak torque available between 1,000-1,200rpm.

This translates to excellent 'lugability' from as low as 850rpm, with the torque piling on from there to provide the pulling power needed to climb hills or get moving from standing starts.

Despite the lack of a roof deflector, with the bug splatter on the trailer nose cone showing how much drag is generated at highway speeds, the FleetStar returned fuel consumption of 45.8 litres per 100km over a 440km run from Melbourne to Tarcutta, at an average speed of 84.2km/h, while similar figures were recorded on the return leg to Melbourne.

The only downside is the low fuel capacity in fuel tanker mode, with the single 550-litre tank on the right-hand side requiring a top up to get the truck back to Mercedes-Benz headquarters at Mulgrave from the Somerton dealership.

Although the wheelbase is a relatively short 3,300mm, the Actros provides a comfortable ride on the combination of front parabolic leaf spring and eight airbag rear suspension, and had no problem soaking up the corrugations of the Hume Highway in and out of Melbourne.

Also impressive is the steering response and assistance, there was only a hint of vagueness at the straight ahead position, while the power steering made it possible to swing in and out of tight spots without breaking into a sweat.

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Verdict

Its market share may not reflect it, but the Actros is an excellent performer in a variety of configurations and brings with it the undoubted cache of the Mercedes-Benz logo.

There is also the high level of standard safety, with only the Voith Retarder, Telligent Proximity Control and Lane Assist optional extras in the 2012 price book, all other safety items are included.

Add to this the low fuel consumption and high average speed, including slowing down for roadwork and towns along the way, and the Actros offers plenty for fleet managers to think about when ordering their next trucks.

 

Likes:

  • Good all-round vision
  • Comfortable ride
  • Excellent fuel consumption
  • Safety package

Dislikes:

  • Small fuel tank
  • Blind spot from mirror clusters

 

Specifications

Make/Model: Mercedes-Benz Actros 2644LS FleetStar

Configuration: 6x4 prime mover

GVM/GCM: 26,000kg/up to 55,000kg

Engine: Mercedes-Benz OM501 LA 11.9-litre V6, turbocharged and intercooled diesel with electronically controlled common-rail fuel injection

Emission Control: Euro 5 with SCR

Outputs: 320kW@1,800rpm/2,100Nm@1,080rpm

Capacities: Fuel — 1 x 550 litres; AdBlue — 1 x 85 litres

Transmission: Mercedes-Benz PowerShift 2 non-synchromesh automated manual 12-speed

Brakes: All-wheel-disc brakes, with ABS, ASR, active brake assist and Telligent stability control

Suspension: Front — parabolic leaf spring; Rear — 8-bag airbag suspension, driver adjustable

 

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