Gray Tractor Farm tractors by year
Gray Tractor built drum-driven tractors during the early twentieth century. The original design was acquired from W.C. Knapp who had been experimenting with tractors since 1908. Gray Tractor began production in Minneapolis in 1914. Gray exported a large number of tractors to France during World War I. Gray Tractor entered bankruptcy in 1924 and was sold. Production resumed with export to Canada until the factory was closed in 1927.
| Model | Power | Years |
| 20-35 | 35 hp[B] | 1914 - 1916 |
| 15-25 | 25 hp[B] | 1915 - 1916 |
| 18-30 | 30 hp[B] | 1917 |
| 18-36 | 36 hp[B] | 1918 - 1921 |
| 20-36 | 36 hp[B] | 1922 - 1924 |
| 22-40 | 40 hp[B] | 1923 - 1927 |
[B]: Engine power estimated from belt horsepower. See individual tractor data listing for power details.