Named after a series of 11 operations conducted by the American Forces in the Vietnam War, the Freightliner Coronado is a worthwhile member of any team – Words by Brenton O’Connor, Images by Geoff Parrington.
The tipper and dog market is booming, especially in NSW and Western Sydney, so the invitation from Daimler Truck and Bus to drive its new tipper demonstrator was an opportunity not to be missed.
The truck in question was a Freightliner Coronado 114 day cabin, fitted with a Hercules alloy body and hooked up to a Hercules alloy quad dog trailer combination. This had been setup to run as a conventional 50.5 tonnes, 19-metre truck and dog (as the set forward front axle of the Coronado 114 meets the infamous ‘bridge formula’ for extreme axle spacing). Alternatively, the truck can be used as a level two HML/PBS (on approved routes) that allows a gross combination mass of up to 57.5 tonnes.
A lot has been done to the Coronado to help with weight distribution due to the extreme forward steer axle location on this truck, and driving these changes has been Michael Egan, senior manager of Freightliner fleet sales. Michael was on hand to explain the key changes and modifications Freightliner has made to create a better spec, and particularly to help with weight distribution.
The front axle on the 114 Coronado is mounted only 756 mm from the bumper to the centre of the steer axle, and, to put that in perspective, the Western Star 4800 is 872 mm and the Kenworth SAR is 870 mm. This extreme forward axle spacing has created weight distribution issues for Freightliner, particularly in rigid tipper applications.
Typically, the wheelbase of choice for Coronado 114 tippers has been 5300 mm; however, the truck tested was some 500 mm shorter at 4800 mm, fitted with a decent length 4.3-metre body. To accomplish these dimensions Freightliner Australia has made a number of changes to the truck and equipment.
The most significant is the exhaust routing, with the exhaust system modified so that the exhaust gas comes directly out of the DPF filter and straight onto the ground, resulting in the removal of the dual stainless-steel stacks normally fitted up each side of the cabin. The reasoning behind this is to be able to move the tipper body right up to the back of the cabin in order to push weight forward onto the steer axle, removing the substantial gap between the cabin and the body where the exhaust system and dual stacks were typically routed.
The next major change has been the fuel tank design and location. Typically, the tipper spec will come with three round tanks – two for fuel and one for hydraulic oil. However, the Coronado as tested was fitted with two short and deep square fuel tanks incorporating integrated steps, that were fitted as far forward as possible to again help get weight forward.
The left-hand fuel tank had been split to give 200 litres of hydraulic oil, and, as such, the truck has a total fuel capacity of 630 litres, which should be plenty for most applications. The only downside of these tanks is that they no longer provide the same ease of access to the cabin as experienced with round tanks when fitted with big wide steps across their full width. A further possible concern is their close proximity to the ground, opening up the possibility of damage if going off-road into construction sites to deliver bulk materials.
Another change has been the fitment of the batteries in cabin, rather than on the left-hand-side of the chassis. The batteries have been fitted underneath the passenger seat to further help move weight forward. Freightliner Australia has also fitted a number of yellow grab handles to make access in and out of the cabin easier, an attention to detail that will appeal to purchasing officers in large fleets who are safety conscious.
The only engine offering on the Coronado 114 is Detroit’s DD15, available in a range of horsepower and torque settings. In this application it was set at 500 hp and 1850 lb-ft of torque. For those wanting extra power it’s upgradeable to a maximum horsepower rating of 560 hp with torque staying the same at 1850 lb-ft.
The DD15 is one of the few engines running a combined EGR and DPF system (rather than SCR) in order to meet its emission obligations, and, whilst to many readers that will be off-putting, it really shouldn’t be.
The DD15 was an engine designed to run EGR from its design phase and not a tack-on to an already existing engine that was never designed from the outset to host EGR. So confident is Detroit of its engine’s success, included (as standard) is a five-year/one-million-kilometre warranty and a minimum of 40,000 km service intervals on B-double work that can be extended even further depending on fuel burn and operating conditions.
The truck tested was fitted with the optional Eaton UltraShift transmission, providing a full two-pedal operation. Freightliner still has the best gear selection method for trucks running this transmission, with its steering-column-mounted ‘paddle shift’ known as SmartShift making both selecting gears, and also manual upshifting and downshifting, easy. Furthermore, it saves space in the cabin and improves access from the driver’s seat into the sleeper cabin (when fitted). Another nice advantage is the integration of the gear selection into the main display allowing the driver to easily identify the gear selected.
Driving the Detroit DD15/Eaton UltraShift package with the loaded combination obviously makes life easy, without needing to operate the clutch or changes gears manually. Like most UltraShift trucks, the transmission is too slow to upshift in the lower gears and requires the driver to manually ‘tap’ the paddle shift to force the transmission to upshift, otherwise the truck revs out to 2100 rpm before it shifts up. On one particular occasion, when leaving the BP truck stop in Epping, the truck wouldn’t shift out of second gear, even though automatic mode was selected, therefore a manual upshift was required to get the transmission to move up through the gears.
When it comes to steering feel, the Coronado 114 excels, which could be in part due to the dual steering boxes fitted as standard to the truck. The steering is both light and direct and has excellent road hold. So much so, that the truck drives as if on rails, and, even when dropped off the edge of the bitumen onto the gravel road shoulder, the truck remains composed and is easy to bring back onto the black top. Going on further, the truck handles extremely well, and when cornering the truck feels very composed and inspires confidence into the driver.
The downside of the road handling is the ride comfort, particularly from the steer axle. While the firm front springs provide exceptional road handling, they are very firm, and on rough roads the truck is quite rough. The rear suspension is Freightliner’s AirLiner 46K airbag suspension, with a four-bag arrangement. The nature of a four-bag tandem-drive airbag setup doesn’t provide the same level of axle articulation, movement and ride comfort when compared to an eight-bag arrangement.
For the test route, a trip was taken from Daimler’s Somerton dealership north up the Hume Highway to Broadford, where the vehicle weight at the checking station recorded a gross combination weight of 46.06 tonnes. From there the route detoured west to Kilmore, then onto Wallan, before returning to the dealership at Somerton. This provided a combination of freeway travel, stop/starts through the towns and also some country highway with less than perfect road conditions, during which the rigid tipper and quad dog combination recorded an average fuel consumption of 1.75 kilometres per litre.
Standard equipment on the Freightliner is outstanding, and, unlike other US trucks, one does not need to delve deep into the options list (with additional costs) to get a decent specification. Power mirrors and windows are standard, as is ABS and traction control, along with full cross locks (differential locks), Michelin tyres and Alcoa DURABRITE rims, all of which make the standard truck both comfortable and well equipped for the range of tasks likely to be thrown at it.
The Coronado 114 is a good package, and the range of changes instigated by Freightliner Australia has sought to make the vehicle more suitable for tipper and dog work, especially with the explosion of PBS truck and dog combinations witnessed in recent years. Unfortunately, as the truck was not loaded to its legal limit, we weren’t able to ascertain how close to 6.5 tonnes on the steer axle the changes made by Freightliner have achieved; however, the technical drawings done by both Freightliner and Hercules indicate that it should be feasible.