Friction-Drive

Light weight coupled with friction-drive drove Heider Mfg. Co.'s success.


| October/November 2003



Tractor's friction-drive

Heider ads touted the tractor's friction-drive, but whether it was any better than a traditional transmission is debatable. This 1920 ad's claim for '12 Years Actual Field Work' is a bit of pitchman's hype; although John and Henry Heider started work on a prototype in 1908, they didn't introduce their first tractor until 1910.

When lowans John and Henry Heider launched the Heider Mfg. Co., Carrol, Iowa, in 1910, they aimed their sights on the light end of the growing market for small tractors. Weighing in at a relatively svelte 4,500 pounds, their first product, the Heider Model A, was powered by a Waukesha four-cylinder engine. Built using mostly outsourced components (a practice the company supposedly maintained throughout its history), the Model A saw limited production. It's estimated that fewer than 40 were built, but the Model A introduced elements that would stick with the Heider name for the next 17 years, particularly its friction-drive transmission.

Friction-Drive

Heider's friction-drive was a uniquely simple device that replaced the traditional transmission. Instead of a transmission coupled to the back of the engine, the Heider had an exposed flywheel with a broad outer surface faced with wood. This was the friction material, which in turn made contact with a cast plate approximately 125 percent larger than the flywheel and set 90 degrees to the flywheel on the same plane. Engine power was transmitted through the friction plate to a simple differential drive, and then out to the rear drivers.

There were two plates, one on either side of the flywheel, and these provided reverse and forward 'gears.' Selection was accomplished by simply drawing a lever that pulled the friction plates to the left or the right. With the left plate engaged the Heider moved forward, and with the right plate engaged it moved backward.

Gayle McDonald's 1918 Heider Model C. Center: Gayle's Heider uses a Waukesha Model M four-cylinder engine. Note the Heider name on the pushrod cover.

Gearing was provided through the positioning of the flywheel on the friction plates. When the Heider's flywheel contacted the outer edges of a plate the drive to the differential was slower, effectively giving low gear. Conversely, when the flywheel contacted the inner areas of the friction plate the drive to the differential was faster, giving a higher gear. The 'gear' lever was equipped with seven detents, but in practice most Heiders were probably operated in about three ranges, high, medium and low. But what really made the arrangement unique was how shifting was accomplished.