When mud or sand have swallowed the road, the only way to stay out of trouble is to keep moving. This is where the highly controllable driven front axle in the Volvo FMX is hard to beat. And even harder to beat now that it is completely redesigned to increase ground clearance and give the truck a real off-road approach angle.
It’s hard to believe the construction segment manager in his clean white shirt has just come home from a mud bath in Brazil. Until he starts talking about the new 8×6 and the redesigned front axle.
Commonly known as the Oh Shit!-button
“The 8×6 has been available for some time, but now it is part of our standard offer, which means shorter delivery times for customers. Strictly speaking, it’s a six-wheel-drive with an extra axle for in-creased load capacity. But with the new front axle it’s becoming a very useful vehicle in borderline conditions – as is the 6×6 and 4×4,” says Jonas Odermalm.
Steeper hills and deeper ditches
The front drive axle has been relocated 100 millimetres closer to the front. This gives the truck a far better approach angle, but also means it can be combined with the full range of chassis components and engines. From crown and pinion to bearings, the axle is completely new. Its design makes it stronger, more streamlined and provides better ground clearance.
“Previously the lowest part was the parallel rod, but this has been integrated behind the axle beam. So now the lowest point of the vehicle is the sturdy axle casing. When fully laden the truck has significantly improved ground clearance. Together with the new approach angle, this makes it very versatile on uneven terrain,” explains Jonas Odermalm.
Lower fuel consumption
While permanent all-wheel-drive is the common solution for construction trucks, Volvo prefers to let the driver engage it – as and when needed. Jonas Odermalm recalls from research carried out in the desert: “It’s really only needed between two and five percent of the time. This means that 95 percent of the time All-Wheel-Drive is a waste of fuel – unless it’s an FMX and the driver can choose when to apply it.”
With a switch on the dashboard the driver can revert to rear-wheel-drive when conditions allow. This means direct transfer between the engine and rear drive axle, so the other wheels are free rolling – and consuming less fuel. On top of this, there is less wear and tear on the front axle.
When things get extreme
In the six-wheel-drive trucks the first thing you need is an inter-axle differential lock – diagonally locking two of the rear drive wheels across the bogie. According to Jonas Odermalm, this is enough for many situations. “If things start getting really slippery you engage the driven front axle. This gets you out of most situations – now we are entering extreme mobility.”
“Then we have what is commonly known as the Oh Shit! button. Pressing this locks the front differential making it very hard to steer the vehicle – but allows you to get back onto dry land.”
On and off
When asked about the attraction of this type of mobility, Jonas Odermalm is quick to respond. “We let the driver determine when more drive axles are needed. I think it’s appreciated by drivers of all sorts of vehicles: 4×4 service vehicles for road maintenance, 6×6 tippers working on desert oil pipes and 8×6 dump trucks in quarries.’’
He adds, “Of course, it wouldn’t be so attractive without our reputation for durability and reliability.”
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