How an Odometer Works

The odometer is a device that informs the user on the miles traveled by a particular vehicle. An odometer is designed in two types, mechanical and electronic. The readout of the mechanical odometer uses 6 rolling disks with numbers 1 through 9. Electronic odometers give you a digital readout of the mileage. Digital odometers are usually part of a larger digital display panel in newer vehicles, odometer displays are usually under the speedometer. 

 
The odometer has been around since around 27 BC. It was first description was by Vitruvius, a Roman writer and architect. His odometer was a chariot wheel four feet in diameter turning 400 times for one Roman mile. There was a 400 tooth cogwheel that turned one complete revolution per mile. This cogwheel engaged another wheel that dropped pebbles one by one into a box. The distance traveled would be measure by counting the pebbles at the end of the trip. Odometers have been used by the ancient Chinese, by the mile markers of Alexander the Great and even Benjamin Franklin. Modern inventors like William Clayton who has created odometers that where separate gears that controlled each digit that we know today.
When purchasing a car the odometer informs you on the wear and tear the car has been through. The main problem with mechanical odometers is that the dials can become worn and the gears can strip. Since the odometer is an internal item there is no preventive maintenance needed. The odometer is equipped with a trip meter call a trip odometer that allows the user to check the mileage of any particular distance separate from the main odometer. The trip odometer can be reset by the user.

Odometer Fraud
One of the most common automotive scams involves the odometer. By rolling back the mileage a buyer can be tricked into thinking there are fewer miles on the vehicle than actually are. Here are some tips to let you know when you are dealing with a car that might have the odometer rolled back:

Look for fingerprints on the inside of the plastic cover over the gauges

Make sure the numbers on the odometer are lined up straight

When you test drive the vehicle, see if the odometer sticks

Check the maintenance record of the vehicle

Look for service stickers that may show actual mileage. These are on the inside of the door or under the hood.

Check the car's title to see if there are any corrections on the mileage.

Ask the repair facility for warranty records, this can be checked from their computer system.

Check the date to see when the title was issued. If the title date is recent then the new title might have been created to hide a mileage change.

Look for wear on any place in the car that someone would have contact with. The steering wheel or arm rests are good examples of this. Does the wear match the odometer reading?

Consult an independent car information website like carfax.com

If you are still in question about any vehicle have it inspected by a local garage. A trained technician can give you an evaluation of the car. These tips and tricks will protect you from this type of fraud the next time you go to buy a vehicle.