# Roadometer Counted Settlers’ Distance Traveled

Fifteen miles per day was the average rate of travel for ox-drawn wagons traveling west in the 1800s. But some settlers weren’t content with a mere estimate of the distance they traveled. In 1847, Mormon pioneers William Clayton and Orson Pratt developed a “roadometer” to provide a rough estimate of the miles their party traveled each day between Omaha, Neb., and Salt Lake City, Utah. The device, made of wooden cogs and gears, recorded wheel revolutions by the mile and quarter-mile.

In the late 1800s, surveyors and topographical engineers used brass wheel odometers to determine distance traveled in a given day. South Dakota collector Willard Zeeb recently acquired one of these unique wagon odometers, which bears an imprint reading “JAS. GREEN BALTIMORE 9.” The odometer is contained in a black leather case and was strapped to the spokes of a wagon wheel to measure the number of revolutions, Willard says.

Mounted inside the leather case is a metal container measuring 4-3/8 inches in diameter by 2-1/8 inches deep with a radius of 13-5/8 inches. On the inside bottom of the container is a tapered circle of brass. The device features a dial attached to a brass weight, which hung down while the frame and worm gear revolved. When the cover is in place, a metal tapered shaft on the measuring device fits into the brass ring. As the wagon wheel turns, the odometer revolves in a circular motion. The grooves on the odometer shaft turn the brass part, which has a pointer with numbers to indicate distance traveled. The round gear parts have numbered teeth of varying size, allowing the mechanism to revolve at different speeds.

The gears were set according to wheel measurement, Willard explains. “If the radius of the wheel was 10 feet, then 528 rounds equaled one mile,” he says. At the end of the day, the surveyor would multiply the number of recorded revolutions by the diameter of the wheel to determine the number of feet traveled. He would then calculate this number as miles, adjusting the number by 1 to 3 percent to account for rough terrain.

Willard says his wagon odometer is in excellent condition, and shows little sign of wear, in part, perhaps, because the introduction of the automobile soon made travel by wagons – and wagon odometers – obsolete. FC

• Published on Jan 14, 2011