Written by Larry Gay
The early row-crop tractors were built with a drop-box type of rear axle to provide the necessary clearance under the rear axle for cultivating row crops. The wheels were spaced for cultivating, which often resulted in side-draft problems when the tractor was used for plowing. This situation changed in early 1930 when the Oliver Hart-Parr Row Crop tractor was introduced. This tractor used 59.5-inch diameter rear wheels attached to a straight rear axle to provide ample clearance for cultivating row crops. The rear wheel spacing was adjustable along the axles, so the wheels could be set in a narrow position for plowing and a wide position for cultivating.
Most people don’t know the development of this tractor was started by a plow and implement company, the Oliver Chilled Plow Works of South Bend, Indiana. The first prototype was built in 1926 and test work started in Texas that year. The rear wheels on the first tractors were interconnected dual steel wheels, but company photos show these were revised to a single ring steel wheel by 1928. These prototypes were built with a 4-cylinder, L-head type Hercules engine and a 3-speed transmission. Mid-mounted implements, such as planters, cultivators, and mowers, were developed at the same time.
On April 2, 1929 (not April 1), the Oliver Farm Equipment Company was formed when the Oliver Chilled Plow Works merged with the Hart-Parr Company, a tractor manufacturer, and the Nichols & Shepard Company, a builder of harvesting equipment. A fourth company, the American Seeding Machine Company, was added on May 17, 1929. After the merger, the row-crop tractor project was transferred to the Hart-Parr division for one more year of development.
The Oliver Hart-Parr Row Crop tractor was introduced with a single front wheel, a 4-cylinder Waukesha-Oliver valve-in-head engine which burned kerosene, a 3-speed transmission, and the large-diameter rear wheels which were named Tip-Toe wheels. After its test at Nebraska, the tractor was identified as the 18-27, its drawbar and belt horsepower ratings. In mid-1931, the single front wheel was replaced with dual front wheels and individual turning brakes on the differential shaft were added. Individual turning brakes which mounted at the end of the rear axle housings were made available for the earlier version of the tractor.
Other early row-crop tractors with large diameter rear wheels adjustable along a straight axle were the Farmall F-12 introduced in 1933, followed by the John Deere A in 1934 and the John Deere B in 1935. Contrary to what a series of books about John Deere tractors state, the John Deere A was not the first tractor with adjustable rear wheel tread.
Larry Gay is the author of four farm tractor books published by the American Society of Agricultural and Biological Engineers, including A Guide to Hart-Parr, Oliver and White Tractors. This book may be obtained from ASABE at 800-695-2723 or asabe.org, click publications and then click history books.