The David Bradley Manufacturing Works was purchased by Sears and Roebuck in 1912 and produced house brand proucts for the retail giant from that point forward. After World War 2 Bradley introduced a two wheel walk behind garden tractor that was produced from 1946 until 1966 that proved to be a very popular product and is what most people think of as a David Bradley garden tractor. According to one account Sears management pressured Bradley to produce the Tri-Trac because they wanted a small riding tractor to compete with the International Harvester Cub. Maybe it was the radical design or maybe it just didn't perform to expectation, for whatever reason the Tri-Trac was only produced from 1954 to 1957 with disappointing sales numbers.
This article also provides a photo of Gabe Kerouac, assembly supervisor, test driving the first Tri-Trac to roll off the assembly line. Unfortunatly the collection of The Pioneer Plowman ends with the March 30, 1954 issue and jumps to the Roper Bradley News of August 1966 so we can't learn more about the Tri-Trac during the rest of its production run. Maybe some day someone will donate the missing issues and the rest of the story will become available.