6 Common Problems With FLX Bikes (Do This Before…)

flx bike problems

Lindsey, do you know who makes Kirkland frozen pizza? This is one of the questions my readers ask a lot. Well, I´ve got you covered.

While FLX bikes are good, they are certainly not without their issues. Although, somewhat thankfully, their issues are far rarer than with other bikes.

We know some people have had issues with them. Our prime focus is purely to talk about the issues that may appear with their bikes.

So, here are the 6 common problems with FLX bikes:

  1. Battery Issues
  2. Noise From Electric Motor Casing
  3. Pedals Make a Clunking Sound During Lengthier Rides
  4. Display Screen Gives Error Messages 
  5. Noisy Motor
  6. Error 21

Remember, most issues will be covered under your warranty. 

1. Battery Issues

One issue that seems to come up time and time again will be battery issues.

Obviously, an electric bike needs a battery to run. It is just a bike without one.

For the most part, FLX bikes do seem to have good batteries in them. However, every so often, you may end up with a battery that doesn’t retain its charge. It may appear to work well the first few times that you use the bike. However, over time, it will start to hold less of a charge.

There isn’t much that you can do about this issue other than reach out to FLX who will be able to replace the battery for you, assuming that your bike is still under warranty.

Read also >> 8 Common Problems With Electric Bikes (Do This Before…)

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2. Noise From Electric Motor Casing

This is something that can occasionally happen when a person is backpedaling on the bike. This is an issue that is likely due to the crankshaft not having enough grease on it.

Remember, the grease is something that will slowly disappear over time.

Thankfully, this tends to be a rather simple problem to fix. You just need to grease the crankshaft. This is easy, and details on how you can accomplish this will be in your FLX bike manual.

3. Pedals Make a Clunking Sound During Lengthier Rides 

At the time of writing, nobody knows what is causing this issue.

It is something that may happen only occasionally. Most people report that the bike sounds fine when they start pedaling. However, after a few miles of cycling, the pedals start to emit a clunking sound.

There is some belief that this may be down to the use of cheaper pedals than other bikes. However, this is unlikely to be the case. It is more likely some components inside of the bike may be a bit looser.

Generally speaking, other than the noise, this isn’t really an issue that you will need to worry about when you are cycling your FLX bike. Nobody has reported issues with their pedals breaking due to this clunking sound, nor do people say that impacts their riding experience in any real way other than the fact that they need to deal with the clunking noise coming from their bike pedals.

Read also >> Bike Chain Noise in High Gear (4 Reasons Why)

4. Display Screen Gives Error Messages  

Sadly, this isn’t a problem that is limited to FLX bikes. Pretty much all of the electric bikes with a display screen will have error messages appear on them every so often.

In most cases, these error messages are telling you that there is a problem with your bike. The error code will tell you what the issue is.

In other cases, the error message may just appear. This is the nature of software glitches and there is not much that you can do about this other than reset your FLX bike, which should only take a few minutes.

The only downside to resetting your display screen module is that you are going to lose any stats that you were using to track your ride. However, for most people, that probably isn’t going to be that much of an issue.

Those that do care about those stats will likely have had them tracked in a different way anyway.

5. Noisy Motor

Many of the earlier FLX bikes were known for having noisier motors, although this is an issue that has been cleared up now.

A lot of people that complained to FLX about the noisy motor were told that they needed to grease it a little bit more and this was part of the basic maintenance of the bike.

Although, one could argue that needing to dismantle a motor in an electric bike goes beyond basic maintenance. In fact, most people would recommend that you do not attempt to service the motor on an electric bike yourself.

Sadly, there isn’t much that you can do about this. Since FLX says that it is a normal issue with bikes and they encourage that a person maintains it themselves, it means that the only option people have here is to deal with the noisy motors.

Although, as we said, this is a problem that you won’t be dealing with if you have one of the later FLX models. 

Read also >> Bike Noise When Pedaling (6 Reasons Why)

6. Error 21

We did note that there are certain errors that may appear if you are riding an FLX bike.

One of these is Error 21, and it warrants its own section. This is because it means that there is an issue with the speed sensor.

FLX claims that if you are dealing with Error 21 on your FLX bike, it means that you are going to need to replace the motor.

This is something that you may be able to do so by making a warranty claim with FLX, but it will be dependent on how long you have had your bike. 


While FLX bikes do not have a huge number of problems (outside of their customer support team), there are some issues that can appear.

Most of these are going to be annoying issues which likely won’t cause lasting damage to your bike but can be tricky to deal with.

Others are issues that can be incredibly tricky to deal with and may require a warranty claim with FLX, or you may need to purchase a whole bike.

The route you go down will be dependent on how long you have owned your FLX bike. 




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John Muranko

John is Founder and Senior Bike Editor at ProBikeCorner. John is a bike and travel addict who has cycled through 17+ countries and doesn't really have any plans of stopping. He´s passionate about helping others by creating technical resources, in-depth reviews and more…

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