Written By Doug Smirnoff

Aostirmotor S18-MINI Common Problems and Troubleshooting


If you own an Aostirmotor S18-MINI Electric Bike, you know that it’s a fantastic ride that can take you places with ease. However, like any other piece of machinery, it may encounter common problems over time. In this guide, we’ll address these issues and provide troubleshooting solutions specifically tailored to the Aostirmotor S18-MINI model.

Aostirmotor S18-MINI Overview

The Aostirmotor S18-MINI is an exceptional electric bike designed to deliver a comfortable and enjoyable riding experience. It boasts a powerful 500W motor with a maximum torque of 80 N.m, ensuring a smooth and effortless journey to your destination. The 20 x 4.0 inch fat tires provide excellent grip and traction on various terrains, enhancing comfort and stability. With reliable disc brakes and full suspension, this bike offers safety and control even in challenging conditions.

Product Details

Recharge Time 4 – 6 hrs
Product Weight 75 lbs
Weight Limit 300 lbs
Frame 6061 Al
Brakes 180 mm Dual Disc
Throttle Half Twist
Bell/Horn Bell
Display Backlit LCD
Tires 20 x 4″ AT Fat
Suspension Full
Cruise Yes
Speed 25 mph
Speed Modes 5
Range 15 – 21 miles (25.7 in our tests)
Waterproof Waterproof
Lights Front/Rear

Causes of Common Problems with the Aostirmotor S18-MINI

This section will address possible problems and solutions specific to the Aostirmotor S18-MINI electric bike.

Common Problems with Aostirmotor S18-MINI

1. Battery Not Charging

Description: The Aostirmotor S18-MINI’s battery is not charging properly, and the bike won’t power up.

Cause: This issue can occur due to a faulty charger, loose connections, or a depleted battery.


  1. Ensure that the charger is securely plugged into both the bike and the power outlet.
  2. Check for any visible damage to the charger or cable and replace if necessary.
  3. If the battery is completely drained, leave it connected to the charger for at least 4-6 hours to recharge fully.
  4. If the problem persists, contact Aostirmotor customer support for further assistance.

2. Motor Suddenly Stops

Description: While riding, the motor on your Aostirmotor S18-MINI suddenly stops working.

Cause: Motor cut-off can occur due to overheating, electrical issues, or a malfunction in the motor itself.


  1. Allow the motor to cool down for a few minutes if overheating is suspected.
  2. Check all electrical connections, including the motor’s wiring harness, for loose or damaged components.
  3. If the motor still doesn’t work, contact a professional bike mechanic for further diagnosis and repair.

3. Display Malfunction

Description: The SW-LCD display on your Aostirmotor S18-MINI is not functioning correctly, making it difficult to monitor your ride.

Cause: Display issues can be caused by loose connections, water damage, or a software glitch.


  1. Check the display’s connection to ensure it’s properly plugged in.
  2. If the display got wet, disconnect it, allow it to dry thoroughly, and then reconnect it.
  3. Try restarting the bike to see if the display functions properly after a reboot.
  4. If the problem persists, consult the Aostirmotor user manual or contact customer support.

4. Brake Squeaking or Grinding

Description: The brakes on your Aostirmotor S18-MINI produce annoying squeaking or grinding noises during operation.

Cause: Squeaky or grinding brakes can result from dirt buildup, worn brake pads, or misaligned brake calipers.


  1. Clean the brake rotors and pads thoroughly to remove any debris or contaminants.
  2. Inspect the brake pads for wear and replace them if they are excessively worn down.
  3. Check and adjust the brake caliper alignment to ensure even contact with the rotors.
  4. If the noise continues, consider consulting a bike mechanic for further brake maintenance.

5. Inaccurate Speed Readings

Description: The speed displayed on the Aostirmotor S18-MINI’s LCD is inaccurate and doesn’t match your actual riding speed.

Cause: Incorrect speed readings can occur due to a sensor malfunction or calibration issues.


  1. Check the sensor connections to ensure they are securely attached and free from damage.
  2. Consult the user manual for instructions on calibrating the speed sensor, and follow the calibration steps carefully.
  3. If calibration doesn’t resolve the issue, contact Aostirmotor’s technical support for further guidance.

6. Uneven Pedal Assistance

Description: The pedal-assist feature on your Aostirmotor S18-MINI provides uneven levels of assistance, making your ride less smooth.

Cause: Uneven pedal assistance can be due to sensor issues, low battery voltage, or a misconfiguration in the pedal-assist settings.


  • Check the sensor connections and ensure they are securely attached.
  • Ensure that the battery voltage is within the recommended range for optimal performance.
  • Access the pedal-assist settings on the bike’s display and adjust them to your preferred level of assistance.
  • If the problem persists, consult the user manual or contact Aostirmotor’s customer support for guidance.

7. Frequent Chain Slippage

Description: The chain on your Aostirmotor S18-MINI electric bike frequently slips or skips gears during riding.

Cause: Chain slippage can occur due to improper chain tension, worn chainring or cassette, or a misaligned derailleur.


  • Inspect the chain’s tension and adjust it to the manufacturer’s recommended specifications.
  • Check the condition of the chainring and cassette; replace them if they show signs of wear.
  • Ensure the derailleur is properly aligned and the gears are shifting smoothly.
  • If the issue continues, seek assistance from a professional bike mechanic.

8. Intermittent Power Loss

Description: Your Aostirmotor S18-MINI experiences intermittent power loss during rides, causing sudden slowdowns or stops.

Cause: Intermittent power loss can result from loose electrical connections, a damaged throttle, or a failing controller.


  • Check all electrical connections, including those for the throttle and controller, to ensure they are secure.
  • Inspect the throttle for physical damage or wear; replace it if necessary.
  • If the problem persists, consult a professional technician to diagnose and repair the controller or other electrical components.

9. Unresponsive Display

Description: The SW-LCD display on your Aostirmotor S18-MINI becomes unresponsive, preventing you from accessing important information.

Cause: Display unresponsiveness may occur due to software glitches, outdated firmware, or display damage.


  • Attempt to restart the display by turning the bike off and back on.
  • Check if there are any available firmware updates for the display and perform the update if necessary.
  • If the display remains unresponsive, contact Aostirmotor support for further assistance or replacement options.

10. Noisy Suspension

Description: The suspension system on your Aostirmotor S18-MINI produces excessive noise, detracting from your riding experience.

Cause: Noisy suspension can be caused by dirt or debris in the suspension components, worn bushings, or loose bolts.


  • Inspect the suspension components for any visible dirt or debris and clean them thoroughly.
  • Check the condition of the suspension bushings and replace them if they show signs of wear.
  • Tighten all suspension bolts to the manufacturer’s recommended torque specifications.
  • If the noise persists, consult a bike mechanic for further inspection and maintenance.

11. Uneven Tire Wear

Description: Your Aostirmotor S18-MINI tires exhibit uneven wear patterns, which can affect stability and performance.

Cause: Uneven tire wear can result from improper tire pressure, misalignment, or overloading.


  • Regularly check and maintain proper tire pressure as per the manufacturer’s recommendations.
  • Inspect the alignment of the wheels and adjust if they are not properly aligned.
  • Avoid overloading the bike beyond its weight limit to prevent excessive tire wear.
  • If the uneven wear persists, consider replacing the tires and consult a professional for alignment adjustments.

12. Loss of Pedal Power

Description: Your Aostirmotor S18-MINI experiences a sudden loss of pedal power, making pedaling difficult.

Cause: Loss of pedal power may occur due to a loose crankarm, worn pedal threads, or a malfunctioning bottom bracket.


  • Inspect the crankarm and ensure it is securely tightened to the bottom bracket.
  • Examine the pedal threads for any signs of wear or damage; replace the pedals if necessary.
  • If the issue persists, consult a bike mechanic to inspect and potentially replace the bottom bracket.

13. Erratic Electric Assistance

Description: The electric assistance on your Aostirmotor S18-MINI behaves erratically, with power surges or drops during your ride.

Cause: Erratic electric assistance can result from a faulty motor controller, loose wiring, or a throttle issue.


  • Inspect all electrical connections, including those related to the motor controller, and secure any loose connections.
  • Examine the throttle for physical damage or wear; replace it if needed.
  • If the problem persists, consult a professional technician to diagnose and repair the motor controller.

14. Gear Shifting Problems

Description: The Aostirmotor S18-MINI experiences difficulties in smoothly shifting gears, leading to gear slipping or misalignment.

Cause: Gear shifting issues can occur due to cable tension problems, misadjusted derailleurs, or worn gear components.


  • Check and adjust the cable tension for precise gear shifting; ensure the cables are not frayed or damaged.
  • Inspect the derailleur alignment and make necessary adjustments to align it properly.
  • If gear components show signs of wear or damage, consider replacing them to improve shifting performance.
  • If the problem persists, seek assistance from a professional bike mechanic.

15. Sudden Loss of Range

Description: Your Aostirmotor S18-MINI experiences a significant reduction in range, running out of battery power much quicker than usual.

Cause: Sudden range loss may be attributed to battery degradation, improper charging, or a malfunctioning battery management system.


  • Check the battery’s health and consider replacing it if it has significantly degraded over time.
  • Ensure you are following proper charging practices, such as using the recommended charger and avoiding overcharging.
  • If the issue persists, consult Aostirmotor support for further diagnosis and potential battery system repairs.

16. Excessive Chain Noise

Description: Your Aostirmotor S18-MINI’s chain generates loud and persistent noise during pedaling.

Cause: Excessive chain noise can be caused by improper lubrication, a dirty chain, or misalignment.


  • Ensure the chain is well-lubricated with bicycle chain-specific lubricant; wipe off excess oil to prevent buildup.
  • Regularly clean the chain to remove dirt and debris that may contribute to noise.
  • Check the chain alignment and adjust it if necessary to reduce noise and improve performance.

17. Unusual Motor Vibrations

Description: Your Aostirmotor S18-MINI’s motor produces unusual vibrations during operation, affecting the overall ride experience.

Cause: Motor vibrations can result from loose motor mounts, damaged motor components, or misalignment.


  • Inspect the motor mounts and ensure they are securely fastened; tighten any loose bolts or connections.
  • Examine the motor components for visible damage or wear; replace damaged parts as needed.
  • Check for any misalignment issues with the motor and its associated components and make necessary adjustments.

18. Inconsistent Speed Control

Description: Your Aostirmotor S18-MINI exhibits inconsistent speed control, making it challenging to maintain a steady pace.

Cause: Inconsistent speed control may be caused by throttle or controller issues, electrical glitches, or sensor problems.


  • Inspect the throttle for physical damage or wear; replace it if necessary.
  • Check for loose or damaged wiring in the controller and electrical connections; secure or replace as needed.
  • Calibrate the speed control settings according to the manufacturer’s instructions to achieve smoother speed adjustments.

19. Battery Drains Quickly

Description: The battery of your Aostirmotor S18-MINI seems to discharge rapidly, reducing your riding range.

Cause: Rapid battery drain may occur due to high power consumption, hilly terrain, or a declining battery health.


  • Adjust your riding style to use lower power modes and avoid aggressive acceleration to extend battery life.
  • Consider the terrain you’re riding on; hilly terrain requires more power, which can drain the battery faster.
  • If the battery health has significantly declined, consider replacing it with a new one for improved performance.

20. Handlebar Issues

Description: The handlebars of your Aostirmotor S18-MINI experience issues such as slippage or difficulty in steering.

Cause: Handlebar problems can result from loose grips, stem bolts, or misalignment of handlebar components.


  • Ensure the handlebar grips are securely fastened; replace them if they are worn or damaged.
  • Check the stem bolts for tightness and make necessary adjustments to prevent handlebar slippage.
  • Inspect the handlebar components for any misalignment and correct it to improve steering and control.

21. Wobbly Wheels

Description: Your Aostirmotor S18-MINI experiences wobbly wheels, affecting the stability and control of the bike.

Cause: Wobbly wheels may result from loose spokes, damaged rims, or improperly seated tires.


  • Inspect the spoke tension and ensure they are properly tightened to the manufacturer’s specifications.
  • Examine the rims for any signs of damage or warping; replace them if necessary.
  • Check the tire seating on the rims and ensure they are seated correctly; adjust as needed.
  • If the wobbling persists, consult a bike mechanic for a more thorough inspection.

22. Loose Pedals

Description: The pedals on your Aostirmotor S18-MINI frequently become loose during rides, posing a safety concern.

Cause: Loose pedals can occur due to insufficient tightening, damaged pedal threads, or worn pedal bearings.


  • Ensure the pedals are securely tightened to the recommended torque specifications.
  • Inspect the pedal threads for wear or damage; replace the pedals if they no longer hold securely.
  • If pedal bearings are worn, consider replacing the pedals or seeking professional assistance for repairs.

23. Brakes Fading Under Load

Description: The brakes on your Aostirmotor S18-MINI tend to fade or lose stopping power when applying brakes under load or downhill.

Cause: Brake fading can result from overheating brake components, worn brake pads, or contaminated brake fluid.


  • Use intermittent braking to prevent excessive heat buildup in the brake system during downhill rides.
  • Inspect the brake pads for wear and replace them if they are thin or worn down.
  • If brake fluid is contaminated, flush and replace it with fresh, clean brake fluid according to the manufacturer’s recommendations.
  • Consider upgrading to larger or more heat-resistant brake rotors if downhill riding is a frequent activity.

24. Erratic Power Display

Description: The power display on your Aostirmotor S18-MINI exhibits erratic readings, making it challenging to gauge battery life and power usage.

Cause: Erratic power display can occur due to voltage fluctuations, loose connections, or display unit malfunctions.


  • Check the battery voltage to ensure it falls within the expected range; recharge if necessary.
  • Inspect all electrical connections related to the power display for tightness and secure any loose connections.
  • If the erratic readings persist, contact Aostirmotor support for guidance or potential display unit replacement.

25. Unstable Kickstand

Description: The kickstand on your Aostirmotor S18-MINI is unstable and has difficulty supporting the bike’s weight.

Cause: An unstable kickstand can result from loose mounting bolts, damage to the kickstand, or an improper kickstand angle.


  • Tighten the kickstand mounting bolts to ensure a secure fit; consider applying thread locker to prevent loosening.
  • Inspect the kickstand for damage and replace it if necessary.
  • Adjust the kickstand angle to ensure it provides stable support when deployed.

Aostirmotor S18-MINI Electric Bike User Reviews

When considering a purchase, it’s essential to hear from those who have already experienced the product. Below, we’ve compiled feedback from Aostirmotor S18-MINI Electric Bike users, gathered from various online sources, with a focus on their positive and negative experiences.

Positive Reviews from Aostirmotor S18-MINI Electric Bike Users

  • Some users were satisfied with the smooth and comfortable ride provided by the Aostirmotor S18-MINI Electric Bike, especially when riding on various terrains.
  • Several users praised the powerful 500W motor, which provided ample acceleration and made uphill riding more manageable.
  • Many users appreciated the user-friendly SW-LCD display, which allowed easy control of the electric bike, including adjusting pedal assistance levels and monitoring ride statistics.
  • Several users commended the bike’s robust construction, with a 6061 Al frame and full suspension, providing a durable and comfortable riding experience.
  • Some users were pleased with the bike’s versatile fat tires, offering excellent grip and traction, even on challenging surfaces, ensuring a smooth and secure ride.

Negative User Reviews of the Aostirmotor S18-MINI Electric Bike

  • Some users were not satisfied with the bike’s weight, stating that it felt heavy and cumbersome, especially when maneuvering or transporting it.
  • Several users reported occasional issues with the electric components, such as the motor or display, leading to unexpected malfunctions and requiring repairs.
  • Some users mentioned that the battery’s actual range fell short of the advertised figures, resulting in shorter rides than expected.
  • A few users expressed concerns about the durability of certain components, such as the brakes, which they found to wear down relatively quickly.
  • Several users noted that while the bike’s suspension improved comfort, it could sometimes feel too stiff or require adjustment for their preferences.

Overall, based on the feedback gathered from Aostirmotor S18-MINI Electric Bike users, it appears that the majority of users were satisfied with their purchase. They highlighted the bike’s comfortable ride, powerful motor, user-friendly display, and robust construction. However, some users did encounter issues related to weight, electric components, battery range, and component durability. It’s important for prospective buyers to consider these user experiences when making their own informed decision about the Aostirmotor S18-MINI Electric Bike.

Aostirmotor S18-MINI Electric Bike Manual

If you are looking for the operating instructions and user manual for the Aostirmotor S18-MINI Electric Bike, you can find them on the manufacturer’s official website.

The manual contains important information on how to properly operate and maintain your electric bike, including safety guidelines and troubleshooting tips. Be sure to consult the official manual to ensure you have the most accurate and up-to-date information for your Aostirmotor S18-MINI.

Aostirmotor S18-MINI Frequently Asked Questions

1. How do I adjust the pedal-assist levels on my Aostirmotor S18-MINI Electric Bike?

To adjust the pedal-assist levels, use the SW-LCD display on your bike’s handlebars. You can select from five levels of pedal assistance to customize your riding experience.

2. What is the recommended maintenance schedule for my Aostirmotor S18-MINI?

The recommended maintenance schedule can be found in the user manual provided by the manufacturer. It typically includes tasks such as checking tire pressure, lubricating the chain, inspecting brakes, and ensuring all electrical connections are secure. Regular maintenance helps keep your bike in optimal condition.

3. Can I ride my Aostirmotor S18-MINI Electric Bike in the rain?

Yes, the Aostirmotor S18-MINI is designed to be waterproof, allowing you to ride in light rain or wet conditions. However, it’s essential to avoid submerging the bike in water or exposing it to heavy downpours, as this can damage electrical components.

4. How long does it take to recharge the battery on my Aostirmotor S18-MINI?

The recharge time for the Aostirmotor S18-MINI battery is approximately 4 to 6 hours. It’s recommended to use the provided charger and follow the manufacturer’s guidelines for safe and efficient charging.

5. What is the weight limit for the Aostirmotor S18-MINI Electric Bike?

The weight limit for the Aostirmotor S18-MINI is 300 lbs. It’s important not to exceed this limit to ensure safe and optimal performance.


Whenever you encounter a problem with your Aostirmotor S18-MINI Electric Bike, it’s advisable to refer to the user manual for guidance on troubleshooting and maintenance. Additionally, don’t hesitate to reach out to the manufacturer’s customer service or a certified service center for assistance. They can provide expert support and ensure that your electric bike continues to perform at its best.

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