Heider Farm tractors by year
Heider Manufacturing built a line of tractors in Carroll, Iowa using their friction-drive system which was a mechanical continuously variable transmission. Heider first began production in 1911 and, by 1912, their tractors were being sold through the Rock Island Plow Company. Rock Island bought out Heider in 1914, although tractors carried the Heider - Rock Island name for several more years.
RockIslandPlowCo.com - fan site dedicated to Rock Island Plow Company
| Model | Power | Years |
| B | 22 hp[B] | 1911 - 1914 |
| C 12-20 | 17 hp[B] | 1916 - 1924 |
| D 9-16 | 17 hp[B] | 1916 - 1929 |
| 6-10 | 11 hp[B] | 1920 - 1926 |
| C 15-27 | 30 hp[B] | 1924 - 1927 |
[B]: Engine power estimated from belt horsepower. See individual tractor data listing for power details.