Last updated on February 12th, 2025
How does an odometer work? In this article, we’ll explain how does a digital odometer work & Which Type Is Best! But first, the basics –
What Is An Odometer?
Contents
An odometer is a device that measures the distance traveled by vehicles, such as cars, trucks, boats, etc. In most cases, the motorcycle’s odometer is located on the handlebars, dashboard, or gas tank. Furthermore, odometer readings help determine when to rotate tires, change oil, and perform other maintenance tasks. To reset the odometer, the vehicle’s transmission system must be changed, which is a very difficult procedure. Therefore, it is very difficult to reset an odometer.
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Types Of An Odometer:
Odometers come in two different types.
- Mechanical odometers
- Electronic odometers
Mechanical Odometers
Basically, a mechanical odometer is an arrangement of cogs with numbers featured on their edges. Moreover, a windowed case hides the mechanical parts and only shows the current mileage and a row of numbers.

How does a mechanical odometer work?
- A mechanical odometer starts with the transmission. Small gears are located in the transmission system that measures the odometer’s progress. This gear is usually attached to the speedometer drive cable.
- The instrument cluster is connected to the other end of this cable. When you start the engine and the car moves, the internal transmission gear turns.
- An internal transmission transmits gear motion to the second set of gears that are attached to a changeable digit.
- In this way, counting starts on the right-hand side of the number’s group.
- This process is repeated until the automobile’s distance traveled causes the left side digits to roll over.
- The process of counting continues until all adjacent numbers reach their apex values.
- A new cycle begins when all the digits are reset to zero. Furthermore, it is not always the case that mechanical odometers are absolutely accurate and precise.
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Electronic Odometers
Electronic odometers are also called digital odometers. In digital odometers, a computer chip tracks mileage and stores it in the engine control module (ECM). Mileage displays digitally on the electronic odometer.

How does a digital odometer work?
It is important to understand how a digital odometer works in order to differentiate it from mechanical odometers that use mechanical components.
- As a first step, digital odometers utilize a magnetic or optical sensor to count your tire’s pulses through a toothed wheel. So, the sensor can record the movements of the toothed wheel whenever the toothed wheel moves in response to the rotation of the tires.
- This sensor will now send the toothed wheel’s movements to the ECU, or engine control unit. It is like a computer that controls everything in the vehicle.
- An automobile’s engine control (ECU) unit is essentially the vehicle’s mainframe. It acts as a local area network and contains all of the data necessary for the dashboard instruments.
- In order to calculate the distance traveled by the vehicle, the ECU will use a mathematical algorithm after receiving data from the sensors.
- The ECU calculates distance based on the “pulses” recorded by the optical sensors and certain values such as tire size.
- Based on how many pulses the ECU receives from the magnetic sensors, the ECU can calculate the car’s mileage.
- In the car’s instrument cluster, the digital odometer reflects the value in digital format.
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Is a Digital Odometer Better Than a Mechanical Odometer? Which Type Is The Best?
Yes, a digital odometer is better than a mechanical odometer.
Reliable:
In today’s modern world, digital odometers are great because they eliminate the need for mechanical odometers, which are unreliable since they can easily be rolled back. In contrast, a digital odometer’s values are recorded in the car’s electronic control unit (ECU), which is difficult to alter. Therefore, if you are buying a newer vehicle, ensure the instrument cluster has a digital display. So that you will be able to not only find your mileage but also keep a good record of it within the vehicle’s electronic control unit.
Efficient & Affordable:
Digital odometers are more technologically advanced. As an added benefit, they are relatively inexpensive to install in your vehicle. This is why mechanical odometers are replacing digital odometers.
The Odometer Serves The Following Purposes:
1- Vehicle’s resale value
It is the odometer reading and the condition of the vehicle that determine a vehicle’s resale value. A car with a high odometer reading but a new appearance will be less valuable than one with a lower odometer reading but in similar condition.
2- Calculate the distance traveled
Odometers calculate fuel economy in kilometers per liter, which helps you decide how much fuel to fill before you go.
3- Existing tire life prediction
During everyday use, the tire undergoes wear and tear. Your odometer reading can tell you how many miles your tires have driven. Moreover, planning tire maintenance or replacements will be easier with this information. The average lifespan of a tire from a reputable manufacturer is about 50000 kilometers. You should check the odometer after each replacement, and then change the tires after 50k kms on the odometer.
4- The maintenance and servicing of a vehicle
There is a specific number of miles that your bike or car must run before it needs to be serviced. Every time you complete a recommended distance, you can take note of the odometer reading so that you can go for servicing afterward.
ODOMETER FRAUD
Tampering with readings is considered fraud, which is punishable under the law. In the automotive industry, odometer scams are very common. Detecting a tampered odometer can be difficult, but not impossible. Furthermore, here are some tips to detect odometer fraud in used cars:
- Take a look at the title and compare the mileage with the odometer on the vehicle.
- Ensure the mileage on the odometer corresponds to the mileage on the maintenance or inspection records of the vehicle.
- Examine tires. You should have the original tires on your car if the odometer shows 20,000 kms or less.
- You should inspect the vehicle’s wear and tear—especially the clutch, brake, and gas pedals—to make sure it fits the mileage displayed on the odometer.
- The odometer of the vehicle should be checked for discrepancies with a vehicle history report. Also, use the vehicle’s VIN to order a vehicle history report online if the seller doesn’t have one.
- You can obtain more information about your car by visiting an independent website like Carfax.com
- An informed evaluation of the vehicle can also be provided by a trained technician.
- In case of suspicion of fraud, contact the law enforcement agency in your state.
FAQ’s
1- Do Digital Odometers Give Accurate Results?
Odometers cannot be guaranteed to be 100% accurate. But it’s great for figuring out a vehicle’s mileage, predicting tire life, and determining a vehicle’s value. Also, odometers with digital displays are considered more accurate than those with mechanical displays due to their advanced technology.
2- Are Speedometers Connected To Odometers & What Does A Speedometer Measure?
Vehicles have odometers attached to their wheels that measure the distance traveled. On the other hand, speedometers measure the vehicle’s speed.
3- Why Is It Important To Check The Odometer?
When determining the worth and value of a vehicle, the odometer reading is an important factor, since it indicates how many miles it has traveled. Vehicles with high mileage are worth less than vehicles with low mileage.
Final Thoughts
An odometer is an important tool to monitor your car’s current mileage and plan ahead for future maintenance. By being aware of how the odometer works, you’ll be better able to trust its readings and use them effectively. Moreover, an odometer can be mechanical, or electronic. Also according to our research, a digital odometer is replacing the mechanical odometer as the most efficient and affordable alternative. Electronic odometers are also better because they have no parts that can be easily tampered with. Despite the fact that odometers cannot provide 100% accurate readings, they are highly useful for calculating a vehicle’s mileage, predicting the life of a vehicle’s tires, and determining the value of a vehicle.
We hope you have enjoyed our article; How Does An Odometer Work & Which Type Is Best!
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