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Why is my bicycle speedometer not working (wired)? It won’t show the speed but the display turns on.

Lorraine B. Jenkin

man riding bicycle on road during daytime

Key Takeaway: A wired bicycle speedometer may not display the speed due to various issues such as loose connections, damaged wires, or sensor misalignment. Troubleshooting steps include checking connections, inspecting wiring, and ensuring proper sensor alignment. Additional tips include cleaning components, checking the battery, and consulting the manufacturer’s manual. Seeking professional help may be necessary if the speedometer still doesn’t function or if there is visible damage.

If you’re an avid cyclist, a casual rider, or someone who relies on their bicycle speedometer for fitness tracking or commuting purposes, you may have encountered a frustrating issue: your wired speedometer isn’t showing the speed, even though the display turns on. Don’t worry, you’re not alone! In this article, we’ll explore why your bicycle speedometer may not be working and provide some troubleshooting steps to help you get back on track.

Bicycle Speedometers

Before we dive into troubleshooting, let’s quickly go over what a bicycle speedometer is and how it functions. A bicycle speedometer is a device that measures and displays your speed while riding. It usually consists of three main components: a sensor, a magnet, and a display unit. The sensor is typically attached to the fork or frame of the bicycle, while the magnet is mounted on a spoke of the wheel. As the wheel spins, the magnet passes by the sensor, generating a signal that the speedometer translates into your speed.

Common Issues with Wired Speedometers

Now that we understand the basic functioning of a bicycle speedometer, let’s explore some common issues that may cause it to stop displaying the speed:

  1. Loose Connections: One of the most common reasons for a speedometer to malfunction is loose connections. Over time, the wires connecting the sensor to the display unit may become loose or disconnected, preventing the speed data from reaching the display.
  2. Damaged Wires: Another potential issue is damaged wires. If the wires connecting the sensor and the display unit are frayed, cut, or exposed to the elements, the signal may not be transmitted properly, resulting in a non-functioning speedometer.
  3. Sensor Misalignment: The sensor and magnet must be properly aligned for the speedometer to work accurately. If the sensor is not aligned correctly or too far from the magnet, it may not detect the magnetic signal, causing the speedometer to fail.

Troubleshooting Steps

Now that we know the possible causes of a non-functioning wired speedometer, let’s go through some troubleshooting steps to get it back up and running:

  1. Check the Connections: Start by ensuring that all the connections between the sensor, magnet, and display unit are secure and properly plugged in. Make sure there are no loose wires or disconnected cables. If you find any loose connections, reattach them securely.
  2. Inspect the Wiring: Carefully inspect the wiring for any signs of damage, such as frayed or cut wires. If you notice any damage, you may need to replace the affected wires or consider rewiring the speedometer. Be cautious when handling the wiring to avoid further damage.
  3. Align the Sensor and Magnet: Check the alignment of the sensor and magnet. The sensor should be positioned close enough to the magnet so that it can detect the magnetic signal as the wheel spins. Adjust the sensor’s position if necessary, ensuring it is securely fastened to the fork or frame of the bicycle.
  4. Clean the Components: Dirt and debris can interfere with the proper functioning of the speedometer. Clean the sensor, magnet, and display unit using a soft cloth or brush. Ensure that there are no obstructions that could affect the transmission of the magnetic signal.
  5. Check the Battery: Some wired speedometers require batteries to power the display unit. Check the battery compartment and replace the battery if necessary. Make sure to follow the manufacturer’s instructions regarding battery type and installation.
  6. Consult the Manufacturer’s Manual: If you’ve tried the above steps and your speedometer is still not working, consult the manufacturer’s manual for specific troubleshooting instructions. Different speedometer models may have unique requirements or additional troubleshooting steps that can help resolve the issue.

Additional Tips and Tricks

Here are a few additional tips and tricks that may help you troubleshoot your wired speedometer:

  • Check for Firmware Updates: Some speedometers can be updated with new firmware to improve performance or address known issues. Visit the manufacturer’s website to see if there are any available firmware updates for your model.
  • Reset the Speedometer: If your speedometer has a reset function, try resetting it to its default settings. This can sometimes resolve software-related issues that may be causing the speedometer to malfunction.
  • Consider Using an App: If all else fails, consider using a smartphone app or a GPS-enabled cycling computer as an alternative to a wired speedometer. These devices can track your speed, distance, and other metrics using the GPS capabilities of your smartphone or dedicated cycling computer.

When to Seek Professional Help

If you’ve followed all the troubleshooting steps and your wired speedometer is still not displaying the speed, or if you notice visible damage to the device, it may be time to seek professional help. Local bike shops or specialized speedometer repair services can diagnose and fix more complex issues that may require specialized knowledge or equipment.

Remember, troubleshooting a wired speedometer requires patience and attention to detail. Take your time to carefully inspect and test each component, and don’t hesitate to seek professional assistance if needed. With a little perseverance, you’ll soon be back on the road, enjoying the benefits of an accurate and functional bicycle speedometer.


Q: Can a wired speedometer be repaired?
A: Yes, in many cases, a wired speedometer can be repaired. By following the troubleshooting steps mentioned in this article, you may be able to identify and fix the issue yourself. If the problem persists or if there is visible damage, it’s advisable to seek professional assistance.

Q: How accurate are bicycle speedometers?
A: Bicycle speedometers can provide reasonably accurate speed readings. However, factors such as tire size, tire pressure, and sensor alignment can affect their accuracy. It’s a good idea to periodically check the speedometer against known distances or use GPS-enabled devices for a more precise measurement.

Q: Can a wireless speedometer be a better alternative?
A: Wireless speedometers offer the advantage of not having wires that can potentially get damaged or require complex installation. They use wireless technology to transmit speed data from the sensor to the display unit. However, they may have their own set of issues such as signal interference or battery life. Choose the type of speedometer that best suits your needs and preferences.

Q: How much does it cost to replace a speedometer?
A: The cost of replacing a speedometer can vary depending on the brand, model, and features of the device. Basic wired speedometers can be relatively affordable, starting at around $15 to $20. However, more advanced models with additional features may cost upwards of $50 or more.


A non-functioning wired bicycle speedometer can be frustrating, but with a little troubleshooting, you can often get it working again. Remember to check the connections, inspect the wiring, and ensure proper sensor alignment. Clean the components, check the battery, and consult the manufacturer’s manual for specific instructions. If all else fails, don’t hesitate to seek professional help. Happy cycling!

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