Simpson Jumbo

From 1947 to 1952, Jumbo Steel Products, located in Azusa, California, manufactured a range of Simpson tractors. The design of these Simpson Jumbo tractors was largely influenced by the Custom tractor from Shelbyville, Indiana. It is possible that Jumbo held a license to produce these tractors for the western United States. The tractors were equipped with Chrysler industrial engines. In 1952, Jumbo Steel was acquired by American Brake Shoe, and the timeline for the cessation of tractor production is sometimes reported to be between 1949 and 1955.