An odometer tracks the distance traveled by an automobile, truck or other vehicle, and is featured in the dashboard. Motorcycles have one fixed at the base of the handlebars, into a dash, or atop the gas tank. It can be mechanical or digital.

A mechanical odometer basically consists of a series of cogs featuring numbers on each edge. The cogs turns in accord with wheel rotation via the cable and drive mechanism. The mechanical parts are hidden from view by a windowed casing that reveals only a single row of numbers, which displays current mileage. This can be viewed on the sppedometer face. Depending on the age of the vehicle, a mechanical odometer might have a maximum count of 99,999 miles, at which point it rolls over to start recounting from 00000 miles.

The modern electronic or digital odometer tracks mileage using a computer chip. The readout is digitally displayed and the mileage is stored in the main engine control module. Manufacturers hoped the electronic version might prevent fraud, but this hasn’t been the case.

Resale value of a vehicle is based in large part on mileage. All else being equal, the fewer miles a vehicle has, the higher the resale value. Odometer fraud or clocking, involves manually setting the readout back to falsely deflate mileage and inflate the value of the car