Four eBike Hub Motor Problems (Find the Fix)

Hub drive electric bikes are undeniably durable, most of those rental ebikes you see are hub drives. But, without proper care and awareness they can get damaged. Most problems are “fixable” but identifying what to fix can be a problem.

Fortunately, the common e-bike hub motor problems are easily fixable, especially if you know what causes them.

Key Takeaways

This article will discuss the following:

• The common e-bike hub motor problems and their solutions
• How to troubleshoot an e-bike hub motor

Knowing what causes problems with your e-bike’s hub motor is essential. Below are the common issues your hub motor may experience and their solutions.

RIDE eMTB Tip: Whenever you’re investigating problems it’s best to take a step back and go back to the basics. I’ve got an article “defining” hub drive motors that can probably help. 👉 What is a Hub Drive eBike

Common eBike Hub Motor Problems And Their Solutions

Problem #1: Noise

Hub motor-equipped electric bikes are notoriously noisy. You commonly hear grinding noises when the e-bike’s bearings, gears, and disc brakes are worn out.

Apart from worn-out gears, tiny debris may also get into the hub motor. As this debris collects into the motor, it may create unnecessary noises while the electric bike is at work. These noises become more noticeable when you cycle slowly, as the wind’s noise does not overpower them. 

If your electric bike has a direct-drive hub motor, you may notice clicking sounds as you decelerate. The two magnetic rings inside the motor, the rotor, and stator, are responsible for these noises.

The stair is the non-moving gear within the motor, while the rotor continuously rotates. The rotor hits the stator when the e-bike’s speed is decreasing, thus producing clicking sounds.

Solution

The first thing you need to do when fixing the noises made by your e-bike’s hub motor is to check what causes the noise. As mentioned, there are three noise causes in a hub motor:

• worn-out gear or loose bolt and bearing
• debris that collected inside the motor
• the collision of the rotor and stator

You need to inspect all these three potential noise causes.

If your bike has worn-out gear, replacing it with a new one will eliminate the noise. But if the gears are still in good condition, you must check and tighten any loose bolts or bearings.

Your e-bike’s hub motor should be quiet after these adjustments. However, there are instances when the gears and bearings are not the problems. In that case, you must open the motor to see if the noise caused is inside it.

Opening a hub motor involves removing the hardware around it. Then, you need a screwdriver to remove the screws to remove the hub cover. You may also need any flat tool to pry the hub cover open.

After opening the motor, check for debris that got into it and remove them. Giving your motor a good cleaning should eliminate the noises it makes during rides.

Moreover, cogging, or the noises made by the rotor and stator clicking together, is uncommon on newer e-bikes. But in the rare chance that it happens to your e-bike’s hub motor, you need to adjust its startup setting to get rid of the noise.

Link To Video: https://www.youtube.com/watch?v=nS4yYY2CBcg

Problem #2: Weak Motor

A weak hub motor causes your electric bike to stop when it is carrying heavy loads. The additional weight stresses the motor, preventing it from functioning as it should. A weak motor can be a persistent problem if you usually load your e-bike with heavy objects, such as a trailer.

When the e-bike’s load is heavy, your motor must draw more power from the battery to support the weight and propel the bike forward. However, weak hub motors cannot get the energy it needs from the battery, so they fail to carry the extra weight you added to their load.

Solution

The only solution to a weak hub motor is to replace it with a new and more powerful one. But while this fix sounds simple, it will cost you a few hundred dollars. Still, it is a valuable investment, allowing your electric bike to carry more loads.

However, your hub motor may still stop even with good quality. Such a problem can happen if the gear inside the motor is already worn-out. If such is the case, you must install a new gear into the motor.

According to a study published in the IJSRD – International Journal for Scientific Research & Development, weight requirements, and power are two considerations when choosing a new hub motor. If you want a lightweight e-bike, choosing a geared hub motor is ideal. Meanwhile, powerful e-bikes will benefit more from a direct drive hub motor.

Problem #3: Hub Motor Fails To Start

Another problem you may experience in an e-bike with a hub motor is its failure to rotate. One of the most obvious signs of this problem is when your turn on the electric bike’s throttle and the rear wheel tries to move. However, the wheel stops even before it completes a full rotation.

The motor may also make a faint sound, like a vehicle that won’t start once you try to turn the motor on. This problem occurs when there is a faulty connection between the motor and the e-bike’s control unit. As a result, the controller fails to pick up power from the battery and deliver it to the motor.

Solution

According to another study published in the IJSRD – International Journal for Scientific Research & Development, an e-bike controller consists of cables that connect to the:

• battery
• hall sensors
• motor
• power lock
• twist throttle

A hub motor usually may not start because of a faulty connection between the e-bike components. So, check all the plugs to ensure none are loose.

The control unit should be able to deliver power from the battery to the motor after you fix all its connections. But if there is no loose plug and the motor fails to start, you may need to replace your control unit with a new one.

Link To Image: https://unsplash.com/photos/3uiLwrKUWVA

Problem #4: Overheating

The common causes of an overheating e-bike hub motor are:

• Incorrect Voltage Supply – when the motor’s voltage is lower than its requirement, it must work harder so that the e-bike will run efficiently. The motor’s components may fail if the voltage exceeds the motor requirements. Both of these problems can result in overheating.
• Weather – if you are e-biking on a hot day, the heat the hub motor produces cannot dissipate, so it struggles to cool down quickly. As a result, the heat stays on the motor’s gear, causing it to overheat.
• Faulty Wiring – a defective wiring system may cause the motor to overheat. This problem can burn the motor and stator winding if not fixed promptly.

Overheating can cause permanent damage to a hub motor, so it is essential to fix it.

Solution

The easiest way to prevent a hub motor from overheating is to ensure no damage to its wiring system. You also need to ensure that the motor size, performance, and voltage are suitable for all the other electrical components of your bike. This way, the power supplied to your hub motor will be enough; thus, nothing will cause it to overheat.

Proper ventilation is crucial to preventing an electric bike hub motor from overheating. While hub motors do not have ventilation holes, you can consider drilling small holes that may act as vents. However, this option may only be ideal if you use your bike on paved roads.

Moreover, consider taking quick yet frequent breaks in shady areas if using your e-bike under extreme weather. This trick will allow your e-bike’s motor to cool down.

Finally, you must inspect your e-bike’s wiring system regularly to ensure it is in excellent condition.

After checking and fixing all the possible causes of hub motor overheating in your e-bike and the problem persists, inspecting the battery is ideal. According to the International Research Journal of Engineering and Technology (IRJET), e-bike lithium-ion batteries may sometimes fail to dissipate heat, causing them to overheat.

RIDE eMTB Pro Tip: the folks at Grin Technologies are the experts when it comes to Hub Motors. Link 👉 HERE

Troubleshooting An eBike Hub Motor

Troubleshooting an e-bike hub motor is essential when you notice something wrong. This way, you can quickly identify where the motor’s problem is coming from, allowing you to fix it promptly.

But how do you troubleshoot a hub motor?

Check the wiring system.

As mentioned, loose plugs between the battery, control unit, and motor are among the most common reasons for e-bike hub motor problems. But apart from loose connections, your e-bike’s wire connections may also become burnt and damaged in the long run.

According to a study conducted by California Polytechnic State University students, broken wires prevent an e-bike’s control unit from picking power up from the battery and feeding it to the motor. These broken wired may short circuit occasionally, causing it to cut off the power supply from the battery to the hub motor. The constant on and off of the motor can cause it to overheat and acquire irreparable damage.

So, if your e-bike’s power turns on and off, you first want to check the wiring system. Fix all the loose, melted, and damaged connections to prevent them from cutting off the power flow to the motor.

Moreover, an electric bike’s motor may also turn on and off even when the entire wiring system does not have any damage. In this case, you need to unplug all the connections to see if dust and debris are built up on their ends. Dust and other dirt buildups are non-conductors of electricity, so they can prevent the battery’s power from traveling to your e-bike’s motor.

Check the hall sensors.

Hub motors have hall sensors, which ensure the proper operation of the e-bike’s controller. If these sensors fail, the controller’s phase current will not match the motor’s power. This problem can cause the motor to overheat.

So, if your e-bike’s motor is overheating and none of the solutions above works, you need to test the hall sensors using a multimeter.

A multimeter works by measuring the hall sensor’s voltage, allowing you to check if it matches the voltage your electric bike’s hub motor needs.

RIDE e MTB Pro Tip: With eBikes growing in popularity learning all the terms and definitions can be a bit overwhelming. Let me help with this comprehensive glossary. 👉 eBike Glossary

Fixing eBike Hub Motor Problems: The Takeaway

Could we help you identify and solve the problems with your electric bike’s hub motor? Knowing how to troubleshoot problems on an e-bike’s hub motor can ensure a smooth ride. The reason is that you can always fix minor issues yourself as soon as they occur.

However, bringing your electric bike to a professional is crucial if the problems you found are more than what a quick troubleshooting can fix.

We’d love to hear your thoughts! If you have comments, suggestions, or tips to add to the list above, please leave them in the comments! You can also share this post with fellow e-bikers to help them with their hub motor issues!

---

Sources

1. Heena, Mr. Sagar D. Mayatra1 Mrs, V. Jadhav2, Mr. Hitesh R. Patel, and Mr. Samkit J. Shah. “A Review Paper on a Design and Development of Hybrid-Electric Luna Moped.” https://www.academia.edu/download/55443302/IJSRDV5I100137.pdf. Accessed February 23, 2023.
2. Khan, Mohammed Hassan, Mohammed Habeeb Ullah Shareef, Md Jameel Ahmed Shakeel, Mohd Faiz Ahmed, and Mohammad Umair Ansari. “Fabrication of e-bike.” Hand 25, no. 250 (2020). https://www.academia.edu/download/64555898/IRJET-V7I5161.pdf. Accessed February 23, 2023.
3. Phadnis Swapnil, S., R. Pandya Vaibhav, A. Patil Mitresh, P. Panchal Mayur, and R. Karekar Raunak. “Design & Development of User Serviceable Battery-Operated Electric Bike with Adjustable Torque.” (2020). https://www.academia.edu/download/64360006/IRJET-V7I4674.pdf. Accessed February 23, 2023.
4. Cong, Robert, Rodney Martinez, Mark Casilang, and Peter Vong. “Electric bicycle system.” (2010). https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1043&context=eesp. Accessed February 23, 2023.