Ultrasonic Cleaning for Chain and Cassette

How often do you clean your bicycle's drivetrain? It is inevitable that it gets dirty through usage, especially if you ride off-road or on wet roads.

Before I converted my Canyon Endurace to a part-time gravel bike, it was a pure road bike which I only rode on roads, and only during good weather. As such, the drivetrain was able to stay clean for a long period of time, before it gets too dirty and needs to be cleaned.

However, ever since I set it up for gravel use, it has seen a lot more off-road usage, which causes the drivetrain to get dirty much more easily and more often. It takes just one wet or sandy ride to generate crunching sounds from the drivetrain, caused by sand and other bits being shifted through the moving parts.

It is the same scenario for the new Cervelo Aspero gravel bike as well. A dirty drivetrain is still usable, just that it will accelerate the wear of the components, such as the cassette, rear derailleur pulleys, chain rings and chain. Therefore, it is a good idea to clean and lube the drivetrain once it gets too dirty. In my case, it is too dirty when the chain looks completely dry with no lube, with lots of gunk around the pulleys.

The drivetrain parts to be cleaned are the cassette sprockets, rear derailleur pulleys, chain rings and chain. I used to clean all these parts, either on or off the bike, by wet tissue or some cleaning agent + rags. It was very time consuming and needed a lot of effort, plus the end result was not very clean.

I decided to try out an ultrasonic cleaner, which uses ultrasonic energy to create lots of tiny cavitation bubbles in the fluid. When the bubbles collapse, it generates high temperature and pressure on a microscopic scale, this is what removes the contaminants on the surface of the material. For more details on ultrasonic cleaning, check out the Wikipedia link.

Small scale ultrasonic cleaners are not expensive, you can get it online or locally from Scootz (in Singapore). I wanted a unit that was big enough to hold a cassette sprocket (ideally the 34T sprocket from the CS-HG800 cassette), to minimize the effort needed to load and unload the ultrasonic cleaner multiple times.

The one that I got has a claimed capacity of 2 litres, which is a good size for most bicycle parts.

Ultrasonic cleaner, with digital settings for the heater and timer.

Close up look at the control panel, where the heater function and timer function can be adjusted and set independently.

Details of the cleaner can be seen at the back. The master on/off switch is here.

Nice smooth stainless steel tank 

Comes with a little basket to hold the items that you want to clean. It has rubber legs to prevent the metal basket from rubbing against the metal tank. 

Here is how the basket fits inside the tank. However, the basket also reduces the usable volume of the tank.

Tested the ultrasonic cleaner for the first time, to see how it works. 

I used a temperature of 60 degrees Celsius for better cleaning effectiveness.

For a start, I tested the cleaning function with some other items, such as the Bike Peddler Take-A-Look mirror that I always use. I added only water and nothing else for this test.

It is quite amazing as once I started the machine, I could see the dirt drifting out from the hidden areas. After the cleaning was complete, it was very clean! It could not have been cleaner even if I had used soap and scrubbed the mirror, as there are many small hidden areas that cannot be reached.

The next step is to try with the chain, as it is very difficult to clean the chain properly even after removing it from the bike. Let's see how effective the ultrasonic cleaner is.

One trick I learnt from reading online guides is to use a ziplock bag, and place the item to be cleaned inside the bag. This prevents the tank from becoming dirty. Make sure to add water around the bag as well, inside the tank.

Using a ziplock bag to hold the dirty chain. I added warm water from the kettle, instead of relying on the built-in heater.

This is with just some hand soap. After 10 seconds this is what you see. 

This is after one cleaning cycle of 10 minutes. Not very effective from what I see...

It seems that the cleaning is not effective, probably because I did not use a proper cleaning agent. Warm water and some hand soap is not strong enough to clean the dirt off the chain.

I went out to get a bottle of degreaser, hoping that it will make the cleaning more effective.

A bottle of expensive degreaser from the nearest bike shop. It came with a spray head that did not even work...

I also found that the ziplock method was not very good, as the chain will rest directly on the bottom of the tank (through the thin walls of the ziplock bag). This caused a lot of vibration, and also scratched the surface of the stainless steel tank.

Instead of using a thin ziplock bag, I changed to a plastic takeaway container, which fitted well inside the tank. This will prevent the parts from scratching the walls of the tank, and also makes it easier to rinse and clean the parts.

Added some degreaser to the warm water, with the chain inside. Remember to add water on the outside of the container!

Much better this time. This is after cleaning the second time with degreaser. 

However, the areas between the links and under the rollers still have quite a bit of dirt.

It seems that during cleaning, the solution may get saturated, or the degreaser may have been used up, which makes it difficult for any more dirt to be removed from the chain. Therefore, the only way is to empty the used solution and to put in fresh water and more degreaser, and repeat the cleaning process.

Finally, after 4 times of ultrasonic cleaning! Duration is 10 minutes each time. The first time probably doesn't count as degreaser was not used. 

Even the hidden areas between the rollers and links are cleaned, which will normally take a lot of brushing with strong cleaning agents.

Next up will be the cassette, which also gets very dirty with usage. Other than the chain and cassette, the rear derailleur pulleys and chain rings also need to be cleaned. For the pulleys, I am not sure if it is a good idea to clean with the ultrasonic cleaner, as it may damage the plastic surface.

As for the chain rings, it obviously does not fit inside the tank. The 34T inner chain ring (Dura-Ace R9100) might fit, but it might damage the chrome surface finishing on it.

Cassette is very dirty as can be seen here. 

This is after I wiped the cassette sprockets with a wet tissue, but before using the ultrasonic cleaner.

After running it for 2 cycles (5 minutes each), this is the result! Perfectly clean, much better than what I can do by hand. Takes much lesser effort as well.

Same for the smaller sprockets. Takes 2 cycles to get them really clean. 

The bigger sprockets does not fit completely into the tank, so you have to rotate it to clean the entire surface. Left side is before cleaning, right side is after.

Super clean cassette! Even a brand new cassette is not so clean. 

Super clean chain, before applying new chain lube. 

Super clean drivetrain!

I am really pleased with the effectiveness of the ultrasonic cleaner. It takes me much less effort to clean them, and yet is much more effective.

Dura-Ace CS-R9100 11-30T 11 Speed Cassette also cleaned! 

Even the spaces between the sprockets are very clean. It is difficult to clean these areas properly even with a brush.

Points to take note:
1) Isolate the ultrasonic cleaning machine in a room, such as the storeroom, to prevent hearing damage from continued exposure.
2) Degreaser and warm water is very effective for cleaning the cassette and chain.
3) Do not put anything flammable into the tank as it will heat up during usage.
4) It may remove pad printing or other surface treatment from the parts to be cleaned. If in doubt, test it out first.
5) As the parts will come into contact with water, try to dry and lube it as soon as possible, to prevent rusting after cleaning. Unless you are using high end parts that are very rust resistant.