Dynamometers gave a way to standardize measurements at horse pulls
A heavy team of Percheron horses being tested on the original Ford-mounted dynamometer at Iowa State College, Ames.
From the 1936 Yearbook of Agriculture.
A modern dynamometer truck owned by the Michigan Dynamometer Assn., Inc., at the 1997 Michigan Great Lakes International.
Photo by Sam Moore
These horses are pulling for all they’re worth ... but that power was difficult to gauge until early dynamometers were put to the task of determining a horse’s maximum pulling power.
Image courtesy commons.wikimedia.org.
A diagram of the dynamometer (built on a 1925 Ford truck) very similar to the ones used for horse pulling contests today.
A diagram of the first machine Professor E.V. Collins built on an International Harvester Auto Wagon chassis to test horses for their normal working load.
From Bulletin 240 by E.V. Collins and A.B. Caine, published in 1926 by the Agricultural Experiment Station, Iowa State College of Agricultural and Mechanic Arts.
At the 1997 Great Lakes International Draft Horse Show and Pull, a team of Belgian horses competes in the Lightweight Class with 3,400 pounds on the sled. The class was won with a 3,205-pound team owned and driven by Neal Slusher of Andover, Ohio, who got the only full pull (27.5 feet) with 3,600 pounds on the sled.