The Duro is a high-mobility off-road truck
in the two to three tonne payload class,
built by Bucher-Geyer AG of Bucher Guyer --> Switzerland.
The Swiss army,
which had been a staunch buyer of the Steyr Puch
held a competition for a new all wheel drive truck,
the contract being awarded to Bucher in 1993.
2000 Duros will be delivered between 1994 and 1999.
The Duro is powered by a 3.8L turbo-charged and intercooled diesel
by VM, well known for making high speed diesel engines.
The gearbox is an Allison four speed automatic.
Bucher's own two-speed transfer case incorporates
a centre differential of the Torsen type.
The axle differentials are also Torsen units having a 2.23:1 ratio
and the hubs contain further reduction gearing with a 4.07:1 ratio.
The truck comes as a 4x4 in two wheelbase options and also as a 6x6.
Pictures by Bucher Guyer AG
The Duro has a conventional ladder chassis
and can be fitted with a wide range of bodywork.
The cab is made of aluminium panels
for corrosion resistance and tilts forward
for access to the engine.
De-Dion suspension is fitted to all axles.
This is quite unusual in an off-road truck,
more commonly being found on sports cars.
The De-Dion system uses a "dead" axle tube to link
the left and right wheels.
The differential is mounted on the chassis and the axle
tube merely keeps the wheels parallel to each other.
Drive is taken from the differential to the wheel hubs
by drive-shafts fitted with c.v. joints.
The De-Dion tube forms the base of a triangle
with two large radius arms which locate it fore and aft,
and a Watts linkage gives lateral location.
On a sports car, the De-Dion suspension is used to reduce unsprung
weight and improve handling.
Extra advantages on a four wheel drive are that
the differential can be raised up out of harm's way
and the dead axle tube can be curved upwards to improve ground clearance.
The disc brakes are mounted inboard which reduces unsprung weight further,
but also makes room at the hubs which are fitted with
drop reduction gearing.
The radius arms of the front and rear axles
are inter-connected on each side of the chassis
by links and a rocker arm or stabilizer.
This resists roll 4wd.sofcom.com --> to the left or
right on both axles together, as in cornering,
but it permits the axles to roll in opposite senses
for axle articulation off-road (see above)
Bucher Duro 1997, manufacturer's Specifications
- cab-chassis truck, 4x4, 2 seats (cab)
- loa: 5835mm, width: 1960mm (body), height: 2600mm (cab)
- wheelbase: 3880mm, track: 1680mm/1680mm, grnd clearance: 360mm
- approach: 47, departure: 32, ramp break over: 152
- weight: 2890kg (unladen), GVM: 6000kg
- payload: 200kg (cab), 2910kg (chassis)
- VM EP638LI, 3749cc, diesel, 6-cyls, turbo, intercooler,
- bore: 92mm, stroke: 94mm
- power: 110kW at 4000rpm, torque: 320Nm at 2100rpm
- transmission: Allison AT 542 4-speed auto,
Bucher V-2GS-TD 15, 2-speed transfer case (with synchro),
hi 0.71:1, lo 1.42:1
Diffs 2.23:1, hub gears 4.07:1
- suspension: De-Dion with coil-springs, brakes: discs (inboard)
- tyres: 275/80R20 XZL/128K tubeless
- NB. Also available as a short wheel base 4x4:
and as a 6x6:
- loa 5070mm, wheelbase 3230mm
- payload: 200kg (cab), 2770kg (chassis)
- loa 6220mm, wheelbase 3230mm (1 to 2), 1150mm (2 to 3)
- payload: 200kg (cab), 3475kg (chassis)