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International KBR-12
International 1947 KBR-12.jpg
International 1947½ KBR-12 tractor
Manufacturer International Harvester Co.
Introduced date mid-1947
Discontinued date 1949
Preceding model K-12
Production locations Fort Wayne, Indiana
No built 1138 (1947-48)
Capacity tons/GVW/GCW 4-6 ton, 28500 lb GVW, 55000 lb GCW
Make Continental
Model R-6586
Fuel gasoline
Cooling water
Cylinders 6
Displacement ci / L 587 ci
Power HP @ rpm 200 @ 2600
Gearbox make (model) Fuller 5C650
Gears (forward speeds) 15 (5-speed x optional 3-speed auxiliary)
Axles & drive
Wheels/drive 4x2
Rear Axle Make (Model) Timken S200P double-reduction
Tires standard/optional 11.00-20 12-ply dual rear / 11.00-24 12-ply dual rear (11.00-22 12-ply in photo)
Shipping weight 10560 lb
List price $7340 (1947)
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By the mid 1940s International needed a more powerful gasoline highway tractor to compete with big-engined models from Mack, Brockway, and other truck makers. The 648 ci engine used in the old A-8 series had been dropped in 1942, leaving International with no big engine of its own. Therefore the company purchased 200-hp 587 ci 6-cylinder engines from Continental for the KR-12 model introduced very late in 1946. The KR-12 was effectively a big-engined KR-11, using the same frame, cab, hood, fenders, front axle, and rear axle but with a stronger Fuller 5-speed transmission. These engine and transmission changes and larger standard tires increased the chassis weight by 1,850 lb and raised the price by nearly $2,300. Production records cited by Crismon (1995) do not list any KR-12s built in 1946 but trucks registered as 46’s have appeared at antique truck shows.  International's publication "Beginning Serial Number List Motor Trucks 1928 1966" shows no production of KR-12's in 1946, but does show 1947 KR-12 production beginning with serial number 643.  Since IH serial numbers always started with 501 for new models, it appears that the 142 KR-12's made in 1946 simply weren't entered in the serial number listing that year.  Interestingly, the Wisconsin Historical Society copy of "Beginning Serial Number List Motor Trucks 1928 1966" has a hand written entry in 1946 for the KBR-12 and KBS-12, indicating the correct "501" starting serial numbers for each series that year.

The mid-1947 upgraded KBR-12 continued with the same basic 28500 lb GVW rating and 55000 lb GCW rating as the KR-12. In 1948 International advertised GVW ratings up to 35,100 lb and GCW ratings up to 66,000 lb for ideal conditions. In 1949 the basic GVW rating went up to 31,500 lb. Also in 1949, the KBR-12 with its Timken U200 double-reduction rear axle was joined by the KB-12, with a Timken R100 hypoid single-reduction axle, and the KBS-12, with a Timken U300 2-speed axle. A few KBD-12 trucks may have been built with Cummins 6-cylinder diesel engines.

Continental R-6586 engine

See also

References / sources

  • Crismon, Frederick W. (1995). International Trucks. Motorbooks International, Osceola, Wisconsin.
  • Mroz, Albert (1996). The Illustrated Encyclopedia of American Trucks and Commercial Vehicles. Krause Publications, Iola, Wisconsin.

External links