a76021-RU-1How wide is a row? 42 inches. Why? That’s the average width of a horse. Historically, row width was determined by how close the horse could be driven to the previous row. Early multi-row equipment adopted the 42-inch standard. Early tractors, built to pull that equipment, froze that standard into steel with drop housings and fixed tread.
But problems arose: a fixed tread imposed limitations on farmers beyond certain specific row spacings. It limited the attaching points available to equipment designers. Plows, which worked to the right of tractors, developed side draft.In 1934, John Deere introduced the Model “A” (above) with answers to all these problems. Two industry firsts, adjustable wheel tread and a one-piece transmission case providing high under-axle clearance, solved the first two problems. And the implement hitch, as well as the powershift, was located on the centerline of the tractor, effectively reducing side draft.

Other improvements on the “A” included: Power lift converted from a mechanical to a hydraulic system, increasing both efficiency and speed of operation. It also provided a “cushioned” drop of equipment.

Differential brakes geared directly to the large drive gears, increasing mechanical efficiency and easing operation.

Farmers welcomed the “A” and its variations so strongly that it became the most popular tractor in the company’s history.

The original “A” was rated at 16.22 drawbar hp and 23.52 belt-pulley hp.

Production Year & Serial Number

A AR, AO, AI AO Streamlined
1933 410000 1936 250000 1937 AO-1000
1934 410008 1937 253521 1938 AO-1538
1935 412866 1938 255416 1939 AO-1725
1936 424025 1939 257004 1940 AO-1801
1937 442151 1940 258045
1938 466787 1941 260000
1939 477000 1942 261558
1940 488000 1943 262243
1941 499000 1944 263223
1942 514127 1945 264738
1943 523133 1946 265870
1944 528778 1947 267082
1945 548352 1948 268877
1946 558817 1949 270646
1947 578516 1950 272985
1948 594433 1951 276078
1949 620843 1952 279770
1950 648000 1953 282551
1951 666390
1952 689880
Copyright© 2003 Deere & Company Archives

 

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