The Bull Tractor Co. produced their first tractor in 1913, the lightweight three-wheeled Little Bull. This was a revolutionary design compared to the heavyweight tractors of the time and was much copied by other manufacturers. The Little Bull proved extremely popular, and within a year the company was the biggest producer of tractors in the USA. The Little Bull was followed in 1915 by the more powerful Big Bull, but by this time farmers were finding that the open gears caused problems when dirt got into them and the three-wheeled design could be unstable on hills. The Bull Tractor Co. became bankrupt in 1920 and most tractor manufacturers reverted to four-wheeled tractors.

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