Written By Doug Smirnoff

Addmotor FOLDTAN M-140 Common Problems and Troubleshooting

Welcome to our guide on troubleshooting common problems with the Addmotor FOLDTAN M-140 Electric Bike. If you own this specific model of electric bike, you’ll find this article invaluable in addressing any issues you might encounter. We’ll provide personalized solutions tailored to the FOLDTAN M-140, ensuring that you can enjoy a seamless riding experience.

Addmotor FOLDTAN M-140 Overview

The Addmotor FOLDTAN M-140 is a remarkable electric bike known for its impressive features and performance. Here’s a brief overview based on the product details and specifications:

Product Details Features
Auldt Folding Electric Bicycle Compact size and folding capabilities
20Ah Samsung Cell Battery Pack Rechargeable and removable 20Ah long-lasting UL-recognized Samsung lithium cell battery
48V * 750W Rear-Mounted MOTOR 750W rear hub motor for smooth gear shifting and extended component life
Detachable Rear Rack, Full-Cover Fenders Use for cargo or child seat; full-cover fenders keep you dry and clean
Step-Thru Folding Frame Compact size and folding capabilities for easy transport
Integrated Headlight & Rear Light Powered by the main battery pack; rear light has brake light function
Battery 48V*20Ah Lithium Battery Samsung Cells, Charging Time 8-10 Hours, Rated For 1,000-1,500 Charge Cycles
Motor Addmotor 48V*750W Integrated Wheel Motor (Rear-Mounted Geared Hub)
Display Addmotor EB 2.0 Multi-Functional LCD Display with USB Port
Throttle Variable Speed Control – 1/2 Twist Throttle
Controller Addmotor EB 2.0 25A Controller, Upgraded to a Chip Type
Headlight/Taillight Powered by Main Battery and Controlled by Uneven Buttons
Integrated Wiring Water-Resistant Connectors and Wiring Harness
Charger 48V*20Ah 5 Pins US Standard DC Charger

Causes of Common Problems with the Addmotor FOLDTAN M-140

This section will address various common problems and provide troubleshooting solutions specific to the Addmotor FOLDTAN M-140 electric bike.

Common Problems with the Addmotor FOLDTAN M-140

1. Battery Not Holding a Charge

Description: One common issue with the Addmotor FOLDTAN M-140 is the battery not holding a charge as expected, leading to reduced riding distance.

Cause: This problem can occur due to a variety of reasons, such as a worn-out battery, improper charging, or a faulty charger.


  • Check the charger and the charging port for any damage or loose connections.
  • Make sure you are using the provided charger and that it is functioning correctly.
  • If the problem persists, consider replacing the battery with a new one from Addmotor’s authorized service centers.

2. Motor Power Loss

Description: Some users may experience a loss of power in the FOLDTAN M-140’s motor, resulting in reduced speed and performance.

Cause: Motor power loss can be caused by issues like overheating, controller problems, or a loose motor connection.


  • Allow the motor to cool down if it has been used extensively. Overheating can reduce motor power temporarily.
  • Inspect the controller and motor connections for any loose wires or damaged components. Secure any loose connections.
  • If the issue persists, contact Addmotor’s customer support for further assistance.

3. Display Malfunction

Description: Some users may encounter problems with the FOLDTAN M-140’s display, such as it not turning on or displaying incorrect information.

Cause: Display issues can arise from software glitches, loose wiring, or a malfunctioning display unit.


  • Restart the electric bike by turning it off and then back on to see if the display resets.
  • Check all wiring connections leading to the display unit for any loose or damaged wires. Reconnect or replace as needed.
  • If the display continues to malfunction, reach out to Addmotor’s support for guidance on potential software updates or replacement parts.

4. Brake Light Not Working

Description: The brake light on the FOLDTAN M-140 may fail to illuminate when applying the brakes, compromising safety.

Cause: This issue is often related to wiring problems, a faulty brake switch, or a damaged brake light assembly.


  • Inspect the wiring connections of the brake light and ensure they are securely connected to the main battery pack.
  • Check the brake switch for proper functioning. If it’s not working correctly, consider replacing it.
  • If the problem persists, consult Addmotor’s service centers for professional diagnosis and repair.

5. Sudden Loss of Power

Description: Some riders may encounter a sudden and unexpected loss of power while using the FOLDTAN M-140, causing inconvenience during their ride.

Cause: This issue can be triggered by various factors, including controller malfunctions, electrical shorts, or overheating.


  • Allow the bike to cool down if it has been used intensively. Overheating can lead to temporary power loss.
  • Check for any loose or damaged wiring throughout the bike’s electrical system. Reconnect or replace wires as necessary.
  • If the problem persists, reach out to Addmotor’s technical support for a comprehensive diagnosis and repair.

6. Uneven Motor Performance

Description: Some riders may notice uneven motor performance, where the bike exhibits inconsistent acceleration or deceleration.

Cause: This problem can arise due to issues with the throttle, controller settings, or uneven tire pressure.


  • Check the throttle for any damage or wear. Replace it if necessary to ensure smooth and consistent control.
  • Review the controller settings and ensure they are configured correctly for your riding preferences.
  • Maintain consistent tire pressure in both the front and rear tires to prevent uneven motor performance.

7. Braking Issues

Description: Riders may encounter problems with the brakes, such as squeaking, reduced braking power, or ineffective braking.

Cause: Braking issues can stem from worn brake pads, misaligned brake calipers, or contaminated brake surfaces.


  • Inspect the brake pads for wear and replace them if they are worn down excessively.
  • Check the alignment of the brake calipers and adjust them to ensure proper contact with the brake discs.
  • Clean the brake discs and pads to remove any debris or contaminants that may affect braking performance.

8. Display Error Codes

Description: Some users may encounter error codes or messages on the display, indicating potential issues with the electric bike.

Cause: Error codes can result from various factors, including sensor malfunctions, electrical faults, or software glitches.


  • Refer to the user manual to identify the meaning of the specific error code displayed on the screen.
  • If it’s a sensor issue, inspect the sensor connections and replace any faulty sensors as needed.
  • Perform a software reset or update, following Addmotor’s instructions, to resolve software-related error codes.

9. Chain Slippage

Description: Chain slippage can occur, leading to gear shifting problems and an interrupted riding experience.

Cause: Chain slippage may be caused by a loose chain, misadjusted derailleur, or worn chain components.


  • Inspect the chain tension and adjust it to the manufacturer’s recommended specifications.
  • Check the derailleur alignment and make necessary adjustments to ensure smooth gear shifting.
  • If the chain is excessively worn, consider replacing it with a new one to prevent further slippage.

10. Loud or Unusual Noises

Description: Riders may notice loud or unusual noises emanating from the bike, which can be distracting and concerning.

Cause: These noises can be caused by loose components, damaged bearings, or worn-out parts in the bike’s drivetrain.


  • Inspect the bike for loose bolts, nuts, or fasteners and tighten them securely to eliminate rattling noises.
  • Check the condition of the bearings in the wheels, bottom bracket, and headset. Replace any damaged bearings.
  • Examine the drivetrain components, including the chain, cassette, and chainrings, for wear and replace as needed.

11. Inaccurate Battery Indicator

Description: Some riders may notice that the battery indicator on the display does not accurately reflect the remaining battery capacity.

Cause: This issue can occur due to calibration problems, a faulty battery sensor, or irregular voltage readings.


  • Recalibrate the battery indicator as per the manufacturer’s instructions to improve accuracy.
  • Inspect the battery sensor and its connections for damage or loose wiring. Replace or repair as necessary.
  • If voltage irregularities persist, consult a professional technician for a thorough inspection of the battery system.

12. Loose Handlebars

Description: Some riders may experience handlebars becoming loose during rides, affecting steering control.

Cause: Handlebar looseness may result from improper assembly, worn stem bolts, or insufficient tightening.


  • Check the stem bolts and handlebar clamp for proper torque specifications and tighten them accordingly.
  • Ensure that the handlebars are correctly aligned with the front wheel and adjust them if necessary.
  • If the issue persists, seek assistance from a bike mechanic to inspect the handlebar assembly.

13. Frequent Chain Derailments

Description: Riders may encounter issues with the chain frequently derailing from the chainrings or cassette, disrupting their ride.

Cause: Frequent chain derailments can result from misadjusted derailleur settings, a worn chain, or a bent derailleur hanger.


  • Adjust the front and rear derailleurs according to the manufacturer’s instructions to prevent chain derailments.
  • Inspect the chain for wear, and replace it if it has elongated beyond acceptable limits.
  • Check the derailleur hanger alignment; if it’s bent, consider straightening it or replacing it for smoother gear shifts.

14. Wobbly Wheels

Description: Some riders may experience wobbly wheels, which can affect stability and ride comfort.

Cause: Wobbly wheels may result from loose spokes, damaged rims, or improper wheel truing.


  • Check the tension of the spokes and tighten any loose ones to ensure even tension across the wheel.
  • Inspect the rims for signs of damage, such as cracks or dents, and replace them if necessary.
  • If unsure about wheel truing, consult a professional bike mechanic for proper wheel alignment.

15. Display Backlight Not Functioning

Description: Riders may encounter issues with the display backlight not working, making it difficult to read the display in low-light conditions.

Cause: This problem can occur due to a faulty backlight, loose connections, or display settings.


  • Check the display settings to ensure the backlight is enabled and set to an appropriate brightness level.
  • Inspect the connections between the display unit and the main bike components for loose or damaged wires.
  • If the backlight still doesn’t work, consider replacing the display unit with a new one from Addmotor’s authorized service centers.

16. Sluggish Acceleration

Description: Riders may experience sluggish acceleration, where the bike takes longer to reach desired speeds.

Cause: Sluggish acceleration can result from low battery power, controller issues, or a damaged throttle.


  • Check the battery’s charge level and recharge it if it’s low to ensure optimal performance.
  • Inspect the controller for any signs of damage or loose connections and address these issues accordingly.
  • If the throttle is unresponsive, consider replacing it with a new one to restore smooth acceleration.

17. Excessive Motor Noise

Description: Some riders may notice excessive motor noise during operation, which can be bothersome and indicate potential issues.

Cause: Excessive motor noise can be caused by loose motor components, misalignment, or worn bearings.


  • Inspect the motor’s mounting bolts and ensure they are tightened securely to minimize vibrations and noise.
  • Check for any misalignment of the motor with the wheel hub and adjust it if necessary for smoother operation.
  • If bearing noise is suspected, have a professional technician examine and replace any worn bearings in the motor.

18. Erratic Throttle Response

Description: Riders may encounter erratic throttle response, where the bike’s speed fluctuates unpredictably when using the throttle.

Cause: Erratic throttle response can be attributed to throttle sensor issues, wiring problems, or controller malfunctions.


  • Inspect the throttle sensor and its connections for damage or loose wiring. Replace or repair as needed.
  • Check the wiring harness for any damaged wires or connectors and repair or replace them accordingly.
  • If the problem persists, consult Addmotor’s technical support for further diagnosis and potential controller replacement.

19. Unresponsive Brakes

Description: Some riders may experience unresponsive brakes, where the brakes do not engage properly when applied.

Cause: Unresponsive brakes can result from worn brake pads, air in the brake lines, or brake fluid leaks.


  • Inspect the brake pads for wear and replace them if they have reached their minimum thickness.
  • Bleed the brake lines to remove any air bubbles, ensuring proper brake fluid circulation for improved responsiveness.
  • If brake fluid leaks are suspected, immediately stop riding the bike and have the brakes inspected and repaired by a professional technician.

20. Loose Pedals

Description: Riders may encounter loose pedals, where the pedals wobble or detach during rides.

Cause: Loose pedals can result from improper installation, damaged pedal threads, or worn crank arms.


  • Check the pedal threads and ensure they are clean and undamaged. Reinstall the pedals securely.
  • Inspect the crank arms for wear or damage and replace them if necessary to maintain pedal stability.
  • If you are unsure about pedal installation, seek assistance from a bike mechanic to ensure proper assembly.

21. Unstable Ride at High Speeds

Description: Some riders may experience instability or wobbling when riding at high speeds on the FOLDTAN M-140.

Cause: Unstable rides can result from tire pressure imbalances, misaligned wheels, or uneven weight distribution.


  • Maintain consistent tire pressure in both the front and rear tires to ensure stability during high-speed rides.
  • Check for wheel misalignment and adjust as needed for proper wheel alignment.
  • Ensure even weight distribution on the bike by properly loading cargo or adjusting the rider’s position for balance.

22. Flickering Headlight

Description: Riders may notice the headlight on the FOLDTAN M-140 flickering or not providing consistent illumination.

Cause: Flickering headlights can occur due to loose connections, faulty wiring, or a damaged headlight bulb.


  • Inspect the wiring connections leading to the headlight for any loose or damaged wires. Reconnect or replace as needed.
  • Examine the headlight bulb and socket for signs of damage or corrosion. Replace the bulb or socket if necessary.
  • If the problem persists, consult Addmotor’s service centers for professional diagnosis and repair.

23. Uneven Tire Wear

Description: Riders may observe uneven wear patterns on the tires of the FOLDTAN M-140, affecting ride quality.

Cause: Uneven tire wear can result from misaligned wheels, improper tire pressure, or overloading the bike.


  • Check the alignment of the wheels and make necessary adjustments to ensure even tire wear.
  • Maintain proper tire pressure as recommended by the manufacturer to promote uniform wear.
  • Avoid overloading the bike with cargo beyond its recommended capacity to prevent excessive tire wear.

24. Pedal Resistance

Description: Some riders may encounter increased resistance while pedaling, making it harder to pedal the bike.

Cause: Pedal resistance can be caused by a misaligned chain, improper gear settings, or a malfunctioning crankset.


  • Inspect the chain alignment and adjust it to ensure proper engagement with the chainrings and cassette.
  • Review the gear settings and ensure they are appropriate for the terrain and riding conditions.
  • If the issue persists, have the crankset and bottom bracket inspected by a professional technician for potential replacement or repairs.

25. Loose Kickstand

Description: The kickstand on the FOLDTAN M-140 may become loose or unstable, making it challenging to park the bike securely.

Cause: A loose kickstand can result from vibrations during riding or improper assembly.


  • Inspect the kickstand’s mounting bolts and tighten them securely to prevent loosening due to vibrations.
  • Ensure the kickstand is properly installed according to the manufacturer’s instructions for stability.
  • If the kickstand remains unstable, consider upgrading to a sturdier kickstand for enhanced support.

Addmotor FOLDTAN M-140 Electric Bike User Reviews

Positive Reviews from Addmotor FOLDTAN M-140 Electric Bike Users

Based on user feedback available on the Internet, here are some positive aspects that Addmotor FOLDTAN M-140 Electric Bike users have highlighted:

  • Some users were satisfied with the impressive range and battery life, allowing them to enjoy long rides without frequent recharging.
  • Many users appreciated the convenience of the pedal assist and hand throttle features, providing them with flexible riding options.
  • Several users found the bikes to perform exceptionally well off-road, providing a smooth and enjoyable riding experience on various terrains.
  • Customers liked the prompt and responsive customer service from Addmotor when dealing with issues, ensuring their satisfaction with the purchase.
  • Multiple users commended the overall performance and comfort of the FOLDTAN M-140, highlighting its suitability for various riding needs.

Negative User Reviews of the Addmotor FOLDTAN M-140 Electric Bike

Here are some summarized negative aspects that users have reported about the Addmotor FOLDTAN M-140 Electric Bike based on reviews from Internet:

  • Some users were not satisfied with occasional manufacturing issues or defects in their bikes, leading to inconvenience.
  • Several users expressed concerns about the company charging credit cards even when products or accessories were out of stock, resulting in delays and frustration.
  • Some users mentioned the need for adjustable cruise control and adjustable shocks as a desired improvement in the bike’s features.
  • Customers reported a lack of communication regarding estimated delivery times for out-of-stock products, requiring them to contact customer service for updates.

Overall, the majority of users seem to be satisfied with their experience with the Addmotor FOLDTAN M-140 Electric Bike. The bike’s impressive range, performance, and comfort have garnered positive feedback. While there have been some manufacturing and communication issues reported, users have appreciated the responsive customer service provided by Addmotor. The FOLDTAN M-140 appears to be a popular choice among electric bike enthusiasts, with users enjoying long rides and versatile riding options.

Addmotor FOLDTAN M-140 Electric Bike Manual

You can find the operating instructions and user manual for the Addmotor FOLDTAN M-140 Electric Bike on the manufacturer’s website. Please visit the official Addmotor website to access the detailed manual for this electric bike, which provides comprehensive guidance on assembly, usage, and maintenance.

Addmotor FOLDTAN M-140 Frequently Asked Questions

Common Usage Questions

  1. How do I turn on and off the Addmotor FOLDTAN M-140 Electric Bike?
    To power on the bike, ensure the battery is securely connected and the key is inserted into the ignition. Turn the key to the “on” position and press the power button if available. To turn it off, simply turn the key to the “off” position and disconnect the battery if desired.
  2. How do I engage pedal assist mode?
    Pedal assist mode can typically be activated by selecting your desired level of assistance on the bike’s display, which varies depending on the model. Once selected, start pedaling, and the motor will provide assistance based on your chosen level.
  3. What is the maximum speed of the Addmotor FOLDTAN M-140 Electric Bike?
    The top speed of the FOLDTAN M-140 may vary based on factors such as rider weight, terrain, and battery charge. However, it is typically designed to reach speeds of up to 25 MPH (miles per hour).

Charging and Battery

  1. How long does it take to fully charge the battery?
    The charging time for the battery of the FOLDTAN M-140 is approximately 8-10 hours when the battery is fully depleted. However, charging times may vary slightly based on battery condition and charger specifications.
  2. What is the expected lifespan of the battery, and how many charge cycles can it endure?
    The 48V * 20Ah lithium battery with Samsung cells on the FOLDTAN M-140 is rated for 1,000-1,500 charge cycles. With proper care and maintenance, the battery should last for several years.


  1. What should I do if I encounter a problem with my Addmotor FOLDTAN M-140 Electric Bike?
    If you experience any issues or problems with your bike, it’s advisable to consult the user manual first for troubleshooting tips. If the problem persists, consider reaching out to Addmotor’s customer service or visiting an authorized service center for assistance.
  2. How can I maintain and care for my electric bike to ensure optimal performance?
    Proper maintenance includes keeping the bike clean, checking tire pressure, lubricating the chain, and ensuring all bolts and fasteners are tightened securely. Refer to the user manual for detailed maintenance guidelines specific to the FOLDTAN M-140.


For any issues or concerns related to your Addmotor FOLDTAN M-140 Electric Bike, it’s recommended to refer to the user manual, contact customer service, or visit an authorized service center whenever possible. Proper guidance and support can help resolve problems and ensure the continued enjoyment of your electric bike.

Addmotor MOTAN M-140 P7 Common Problems
Aostirmotor S18-MINI Common Problems
Aostirmotor Hero Common Problems

Leave a Comment