Celebrating National Odometer Day

May 12, 2022

Today is National Odometer day!

We’re going to take a little trip back in time to explore the History of the Odometer/Speedometer in modern day motor vehicles. Find out why they were created and how they work, and impress your friends on trivia night!

Who invented the odometer?

Did you know that both the Ancient Chinese and Ancient Greeks were pioneers in modern automotive engineering? That’s right, the word odometer, which literally means “path measure” in Greek, was first used by the Ancient Chinese and Ancient Greeks to measure distances and assist in the building of roadways and paths. In Ancient Greece, the odometer was created by Hero of Alexandria; in China this technology was independently invented by Zhang Heng of the Han Dynasty. Both of these early devices were a measuring system attached to a two-wheeled pull cart in a chariot or carriage style.

The system was improved upon in 1698, when the first odometers appeared in seafaring ships, thanks to the work of English inventor Thomas Savery. In 1775, Benjamin Franklin created a prototype odometer attached to his postal service carriage to track the mileage on his routes, thus pioneering the first version for driving on roads. In 1903, brothers Charles and Arthur Warner patented the “Auto-Meter” which were the first automobile-friendly odometers; their tech was used in the majority of US manufactured vehicles. In the 1970s, a digital odometer began to emerge onto the market and quickly gained popularity. By the early 2000s, most mechanically operated odometers had been phased out of production.

How does an odometer work?

Odometers generally count wheel rotations, and use a formula calculating the number of rotations multiplied by the tire’s circumference. This is part of the reason why it’s very important to maintain your tire treads, as underinflated or very worn tires can affect an odometer’s mileage tracking process. Likewise, if your vehicle is equipped with after-market and non-standard tires or wheels, the odometer reading may not be as accurate. As a result of these shifting variables and modified possibilities, odometer readings can be off by several percent.

The formula by which odometer readings are calculated for a motor vehicle:

(Actual Distance Traveled) = (Final Odometer Reading – Initial Odometer Reading) multiplied by (actual tire diameter) divided by (Standard tire diameter)