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|Type||2 1⁄2-ton 6x6 trucks
5-ton 6x4 trucks
|Place of origin||United States|
|Specifications (U1 Cargo)|
|Weight||9,875 lb (4,479 kg) empty|
|Length||20 ft 11 in (6.38 m)|
|Width||7 ft 4 in (2.24 m)|
|Height||7 ft 3 in (2.21 m) top of cab
8 ft 10 in (2.69 m) overall
|Transmission||5 spd. x 2 range trf. case|
|Suspension||Beam axles on leaf springs|
|236 mi (379.8 km)|
|Speed||45 mph (72 km/h)|
The Studebaker US6 (G630) was a family of 2½-ton 6x6 and 5-ton 6x4 trucks manufactured by the Studebaker Corporation and REO Motor Car Company during World War II. The basic cargo version was designed to transport a 5,000 lb (2,300 kg), 12 ft (3.7 m) long cargo load over all terrain in all weather. Most were exported to the Soviet Union.
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In 1939 the US Army Ordinance Corps set standards for a 6×6 truck with a 2 1⁄2-ton (5,000 lb (2,300 kg)) off-road payload. Studebaker, Yellow Coach (a GM company), and International Harvester submitted designs. All three were accepted and in production by 1941.
The US6 was built primarily for export under the Lend-Lease act, the Soviet Union would be the largest operator. Production began at Studebaker's South Bend, Indiana, truck plant in June 1941, in 1944 REO's Lansing, Michigan plant would also build them.
A total of 219,882 2 1⁄2-ton (2,268 kg) 6x6 and 5-ton (4,536 kg) 6x4 trucks in thirteen variations were built. Studebaker was the primary manufacturer, building 197,678, while REO sub-contracted 22,204 more. REO trucks are identical to Studebakers, but REO only built long wheelbase without winch models.
Engine and driveline
The US6 used a Hercules JXD engine, a 320 cu in (5.2 L) L-head inline 6 cylinder gasoline engine developing 86 hp (64 kW) at 2800 rpm and 200 lbf·ft (271 N·m) of torque at 1150 rpm. A conservative and reliable engine with a compression ratio of only 5.82:1, it could use 72 octane gasoline. This engine was also used in the M3 and later M8/M20 armored cars.
The Timken T-79 transfer case had high and low ranges, a neutral position, and engaged/disengaged the front axle. There was one output shaft forward to the front axle (not used in 6x4s) and two shafts to the rear, one for each rear axle.
Both front and rear axles were Timken split types with a 6.6:1 ratio. The front had ball-type constant-velocity joints, the rears were full-floating.
There were two wheelbases, the short 148 inches (3.76 m), used in semi tractors, dump trucks, and short cargo models, and the long 162 inches (4.11 m), used in tankers, long cargo models, and the U9 chassis cab (measurements are from the centerline of the front axle to the centerline of rear bogie). All models had 7.50-20” tires and dual rear tires. 6x4 models, intended for on road use only, were rated at 5 tons (4536 kg), twice the 6x6’s off road rating.
The US6 used Studebaker’s civilian truck cab, modified for military use. Studebaker trucks were unique from other 2 1⁄2 trucks built for the war effort because vent windows were included in each door. These windows were separate from the window that rolled down into the door and could be rotated out to help with ventilation.
Studebaker designed the open military cab also used by the CCKW, but their major customer, the U.S.S.R, preferred the closed cab for their climate. While Studebaker's open cab became the US standard, the US6 returned to the closed cab after only 10,000 units.
The U1 and winch equipped U2 cargo truck had a short wheelbase and the spare tire mounted behind the cab, allowing a bed only 9 ft (2.74 m) long. These “prime mover” style bodies were not a success, the US6 was to be used primarily for cargo.
The U3/U4 and 6x4 U7/U8 cargo truck had a long wheelbase, allowing the spare tire to be mounted under a 12 ft (3.66 m) bed. 197,000 trucks with the 12 ft (3.66 m) bed were built.
The U5 gasoline tank truck had a long wheelbase and a two compartment 750 U.S. gal (2,800 l) tank body. Tankers did not have winches.
The 6x4 U6 semi tractor was the only tractor in the series. Semi tractors have limited off-road performance, so the U6 was rated for a 5-ton load on improved roads. For the same reason, they had no front winch.
The U9 chassis-cab had a long wheelbase and no winch. The Katyusha rocket launcher could be mounted on them.
The U10/U11 end dump trucks and the U12/U13 side dump trucks had a short wheelbase. Both had the body mounted on a sub-frame, the end dumb had a hydraulic cylinder attached to the body with a lever arrangement, the side dump had the cylinder mounted directly to the body.
(U2 with winch)
|Short||20 ft 11 in (6.38 m)||7 ft 4 in (2.24 m)||8 ft 10 in (2.69 m)[c]||9,875 lb (4,479 kg)|
|U3 Cargo (long)
(U4 with winch)
|Long||27 ft 11 in (8.51 m)||7 ft 4 in (2.24 m)||8 ft 10 in (2.69 m)[c]|
|U5 Tanker ||Long||20 ft 11 in (6.38 m)||7 ft 4 in (2.24 m)||7 ft 3 in (2.21 m) [d]||10,585 lb (4,801 kg)|
|17 ft 3 in (5.26 m)||7 ft 3 in (2.21 m)||7 ft 2 in (2.18 m)[d]||8,190 lb (3,710 kg)|
|U7 Cargo (long)
(U8 with winch)
|27 ft 11 in (8.51 m)||7 ft 4 in (2.24 m)||8 ft 10 in (2.69 m)[c]|
|U9 Cab/chassis||Long||7 ft 3 in (2.21 m)||7 ft 3 in (2.21 m)[d]|
|U10 End dump
(U11 with winch)
|Short||18 ft 9 in (5.72 m)||7 ft 4 in (2.24 m)||7 ft 7 in (2.31 m)[e]||10,150 lb (4,600 kg)|
|U12 Side dump
(U13 with winch)
|Short||18 ft 11 in (5.77 m)||7 ft 4 in (2.24 m)||7 ft 7 in (2.31 m)[e]||10,150 lb (4,600 kg)|
- With winch add 1 ft 3 in (0.38 m).
- With winch add 610 lb (280 kg).
- To cargo area tarpaulin bows.
- To top of cab.
- To top of dump body cab shield.
Large numbers of Lend-Lease Studebaker trucks were sent into the Soviet Union via the Persian Corridor. The Soviets found them a good platform for "Stalin Organ" Katyusha rocket launchers, although it was not their prime use in the Soviet Union. It fulfilled many roles in the Red Army, such as pulling artillery and was renowned for its ruggedness and reliability. The truck was affectionately known as the Studer by Soviet troops.
- List of U.S. military vehicles by supply catalog designation
- List of U.S. military vehicles by model number
- GMC CCKW
- TM 9-807 (1943). "2 1⁄2 ton 6x6 Truck and 2 1⁄2 to 5-ton 6x4 truck". US War Dept. pp. 14–16, 138. Retrieved 24 Feb 2016.
- Crismon, Fred W (2001). US Military Wheeled Vehicles (3 ed.). Victory WWII Pub. pp. 184, 328–329. ISBN 0-970056-71-0.
- Doyle, David (2003). Standard catalog of U.S. Military Vehicles. Kraus Publications. pp. 122–124. ISBN 0-87349-508-X.
- TM 9-807 (1943), pp. 138-139.
- Crismon (2001).
- Doyle (2003).
- TM 9-2800 (1947). "Military Vehicles". US Dept. of the Army. p. 274. Retrieved 24 Feb 2016.
- TM 9-1807 (1944). "Power Train, Chassis, and Body for 2 1⁄2 ton 6x6 Truck and 2 1⁄2 to 5-ton 6x4 Truck (Studebaker US6 and US6x4)". US War Dept. pp. 22–23. Retrieved 24 Feb 2016.
- TM 9-1807 (1944), pp. 43-44.
- TM 9-1807 (1944), pp. 84-87, 127-129.
- TM 9-807 (1943), pp. 289-290.
- TM 9-1807 (1944), pp. 177-179.
- TM 9-807 (1943), p. 14.
- TM 9-1807 (1944), pp. 211-216.
- TM 9-2800 (1947), p. 280.
- Studebaker/Reo US6 2.5 Ton Cargo Truck images and details
- Australian Studebakers US6
- US 2.5-ton 6x6 Trucks in World War II
- Studebaker/Reo US6 at The-Bluprints.com
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