Roadometer (odometer)

One such device was invented in 1847 by William Clayton, Orson Pratt, and Appleton Harmon, pioneers of the Church of Jesus Christ of Latter-day Saints.

[1]: 87  He tired of counting wheel revolutions and wanted a device that could measure the distance a wagon travelled.

[3] Clayton used their invention to provide an estimate of the distance their party traveled each day between Omaha, Nebraska, and Salt Lake City, Utah.

[1]: 94  Clayton published the distances and other helpful travel information in his popular The Latter-day Saints' Emigrants' Guide.

He gave his odometer to the Deseret Museum in Salt Lake City, and it was on display with accurate information from 1876 until it closed for a period in 1903.

When the museum reopened in 1911, they displayed his odometer with the incorrect information that it had been made by Appleton Harmon and William Clayton.

[1]: 96–98, 103–104  Steven Pratt created a replica of Clayton's odometer which was on display at the Museum of Church History and Art.

Replica of the 1847 roadometer, handmade by Jeff Niven using Larry Howell's measurements
Replica of the 1847 roadometer at the Provo Pioneer Village. Jeffrey Niven created this replica with hand tools. He referenced the machine-cut replica created by Joey Jacobson, which used Larry Howell's calculations of the dimensions. Those calculations came from historical sources.
Video of how the axle interfaces with a replica of the 1847 pioneer odometer.