Foden's early snow mobile
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by Bryan Jarvis • Foden's launch of a new 4x4 gritter/snow plough chassis in flaming June may seem bizarre but council contractors need time to run trials and order them before being bodied in tune for early November frosts.
After the IWM Exhibition launch, Powys Council ordered six and others like Somerset, Blaenau Gwent and Scottish Highland Region are interested.
So Conintercial Motor decided to take a closer look at Foden's new 4x4 in the form of sonic off-road driving.
The S104x4R2 has wheelbases from 3.75m to 6.2m. Two power options are offered; the standard 180hp Cummins 13Series with Eaton 4106A sixspeed synchro box or the 210hp 13-Series with Eaton 520613 box.
The unusual permanent fourwheel drive transmission includes Steyr's VG750 twospeed transfer gearbox, an 11tonne rated Rockwell S153E rear axle and 7.5-tonne rated Sisu DEB front axle.
Diff-locks are standard in both axles and the transfer box. There's also an optional 90tootle Sisu axle that caters for the use of a heavy snow plough blade.
The DEB axle's double uni
versal joints' tapered shoulders contribute towards an impressive 48° lock angle and 15.6m (51.2ft) kerb-to-kerb turning circle.
For gritter/snow plough use you need constant hydraulic power so instead of a gearbox PTO there's an engine-driven hydraulic pump. A drive shaft passes through the radiators, leaving 20% less charge-cooler area, but the gap in the centre gives extra cooling to the main radiator. Foden offers a cheaper crankshaft belt-driven option.
In high range the Foden 4x4's theoretical maximum speed is 94km/h (59mph) in top but is held at the 56mph legal limit. Yet such is its gearing that it can still manage 35mph in low range top cog.
With a quite reasonable 21° approach and 47° departure angles its 29.8% (1-in-3.4) gradeability in high range and 59.5% (1-in-1.7) in low is impressive, so long as the tyres stick to the ground.
The Steyr box accepts some mis-matching of tyres and the rear axle, which has hub bearings specially designed to accept heavy offset loads, will take twin or single rear wheels.
The 295/80s limit the front axle to 7.1 tonnes whereas 315/80Rs give it a 7.5-tonne plate. Unbodied and on twin 12R 22.5 rear tyres the Foden 4x4 weighs 5,580kg including driver and full 230-litre tank.
Driving impressions
CM drove a Foden 4x4 around the Bagshot test tracks and, despite its unladen state and minus its front plough attachment, its potential is unmistakable. With a 0.76m (30m) bottom third step, cab entry is difficult for anyone of normal height but Foden is about to fit a lower spring-loaded step. Over rough ground the big comfy 17-tonner cab is appreciated, even though the air intake banged against it on the passenger's side.
Big drivers will not feel too restricted inside as the steering wheel adjusts and the seat has plenty of rearward travel. As well as broad all-round vision outside the instrumentation is clearly and neatly positioned. This includes the three (front, rear and centre) pneumatic difflock switches on the right beneath the dash.
With its shallow angled accelerator pedal and easy clutch movement, the Eaton 4106's synchromesh gears were smooth enough for its short life (7,500km). Selecting four-wheel drive or low ratio is easy using the flat unobtrusive switch to the left of the driver's seat but Foden recommends stopping the vehicle first.
Even with twin rears, it handled gravel-covered woodland 1-in-3s with impunity but then, so too could any 4x4 worth its salt. Without a full load it's impossible to judge its real ability but it feels capable of achieving its theoretical gradeability.
CM will be testing a number of fully laden 4x4s before the winter and the Foden S104x4R2 will be included.