Written By Larry Gay
During the 1930s, most of the major tractor companies continued to offer a variety of sizes of standard-tread tractors. Usually there was a standard-tread version for each size of row-crop tractor plus one larger size that was available only in a standard-tread configuration. In 1938, the Avery Farm Machinery Company of Peoria, Illinois, (the third organization of the company after being in bankruptcy in 1924 and again during the Great Depression) introduced the Avery Ro-Trak tractor which was a combination row-crop and standard-tread tractor. The ability to change configurations made the Ro-Trak unique.
The Avery Ro-Trak was a streamlined, 2-plow tractor with each front wheel mounted below a vertical cylinder. The cylinders were attached to swing arms which permitted the front wheels to be positioned on each side of the front of the tractor for a standard-tread configuration or together in front of the tractor for a row-crop configuration. The front position resulted in a longer 100-inch wheel base and provided space on the sides of the tractor for mounting a cultivator. The front wheel tread was 16 inches as a row-crop tractor and 56 inches as a standard-tread tractor. The rear wheel tread could be set at 56 inches which enabled two wheels to run in the furrow when plowing or at 84 inches for cultivating. Other intermediate settings were available for crops planted in 24- to 30-inch rows or in 14- to 18-inch rows.
Avery advertised that on most farms the position of the front wheels would need to be changed only twice a year. The standard-tread position could be used for plowing, seed bed preparation, and planting. Then the tractor would be changed to the row-crop position for cultivating. The second change would return the tractor to the standard-tread configuration for combining, corn picking, and highway hauling. The company said one man with wrenches and a jack could change the position of the front wheels in 30 minutes.
The Ro-Trak was powered by a 6-cylinder Hercules engine which was matched with a 3-speed transmission with a maximum speed of 18 mph. The vertical cylinders contained springs which enabled each front wheel to act independently when traveling over bumpy ground. Rubber tires were standard equipment and the PTO, belt pulley, fenders, and headlights were optional. Unfortunately, the Ro-Trak tractor was short lived, because R. G. LeTourneau bought the company in 1941 and started using the factory to build earth moving equipment for the war effort.
Larry Gay is the author of four tractor books published by the American Society of Agricultural and Biological Engineers, including Farm Tractors 1975-1995 and Farm Tractors 1995-2005. The four books may be obtained from ASABE by calling 800-695-2723.