How Does a Speedometer Work?
Speedometers in a vehicle are simple yet useful equipment that serves an important purpose. It enables the driver to keep an eye on the speed of the vehicle and avoid speeding fines. Other than that, you can also track the mileage or the distance traveled by the car. Here we will guide you about different types of speedometers and their working.
Types of Speedometer
There are two main types of speedometers based on their mechanism.
- Analog or mechanical speedometer
- Digital or electronic speedometer
The Analog Speedometer
The analog or mechanical car speedometer shows the speed with the help of a needle. It is mechanically connected with the outer shaft or gearbox. The speedometer consists of multiple parts that work together and show more precise speed. Let’s take a look at how it works.
Working of Analog Speedometer
The speedometer of a car measures speed by using basic laws of physics. The driveshaft spins the wheel and the connected speedometer cable. This movement forces the magnet inside the speed cup to rotate in the same direction. The rotation of the magnet creates torque which forces the speedcup to rotate at the same speed. However, the hairspring is attached with the speedcup to restrict its complete rotation. The pointer that is attached with the speedcup moves over the dial and shows the speed.
Working of Analog Odometer
Every car speedometer is attached to an odometer, which measures the distance a car has travelled. Here is how it works:
- An internal cable attaches a speedometer and an odometer.
- At the end of the cable there is a gear.
- This gear rotates other gears to move the barrels.
- The barrels contain numbers from 0 to 9.
- Each barrel is arranged in a way to rotate the other barrel once a speedometer cycle is completed.
The Digital Speedometer
Modern vehicles with electronic systems tend to have a digital speedometer. It works on the basis of sensors and chips, exempting mechanical connections between the shaft and car speedometer. It consists of the following parts: magnet, magnetic sensors, electric circuit, LCD display.
Working of Digital Speedometer
The magnets are attached to the outer shaft with the magnetic sensors on the opposite side. Each time the magnets cross sensors an electric pulse is generated in the circuit. The circuit turns this pulse into speed and displays it on the LED display. Since the number of wheel rotations are measured, it can also display odometer reading on the same. See the following list of affordable used cars with the best digital speedometers.
- Used Mercedes-Benz S-Class for sale in the UAE
- Second-hand Tesla Model 3 for sale in the UAE
- Used Porsche Panamera for sale in the UAE
- Second-hand Mercedes-Benz E-Class for sale in the UAE
Which type of speedometer is more precise?
The mechanical speedometer is the older version with higher calibration. Whereas, the digital speedometer for cars is considered more viable due to the clear display. Both the speedometers are equally important in the modern vehicle.
Can you change a speedometer from mph to kph?
Yes, you can change it to digital speed in the cluster where it shows the board computer information. Go to the iDrive settings and change the unit into km/h.
Does increasing wheel size affect speedometer?
Yes, it will show a lesser speed of the vehicle than the actual one. Due to the larger size of the wheel its circumference increases and causes it to travel more distance per revolution than the original one.
The main purpose of the car speedometer is to gauge and show the correct speed of the vehicle. The car speedometer calibration is based on multiple auto parts attached with it. Malfunctioning of even the smallest part can result in inaccurate speed measurement. You must know the accurate speed of your car to avoid traffic violations in the UAE. If you are looking for used cars for sale in the UAE, make sure it has a properly functioning speedometer that measures and displays accurate speed.
Stay tuned with the autos blog in the UAE for more information on car accessories.