How to: Clean your bicycle gear cassette and make it look like new
A few weeks ago I decided it was time to replace my Shimano HG53 9-speed chain on my Vivente World Randonneur bike after 22 months of use and about 9,500 km of all-season touring and commuting. To be honest I think I left it too long, as it got to the point that the chain was slipping on certain gears and making more noise than it should.
The intervals of when to replace your chain is something that is quite flexible as there are so many variables that will affect chain wear and how often you should replace the chain. It really depends on how many kilometres you ride, what conditions (sand and water causes wear and corrosion), how often you clean, degrease and lubricate the chain, what type of lubricant you use and how well you have applied it, and so-on. One way of checking if your chain is due for a replacement is by measuring the chain length (more info here). Although I have to admit that I basically just kept the chain as clean and well-oiled as possible, and then just changed it when I felt it was due. A new, superior Shimano HG-73 replacement chain cost a $25 including postage, took about 10 minutes to replace (not including cleaning the cassette) and has made a huge difference in performance, comfort and and ease of use. I immediately noticed less chain noise, gears changes smoother and easier and the chain slip on certain gears also stopped.
Now the general rule of thumb is that, as long as you keep your driveline clean, maintained and correctly oiled, you should get on average two chains to each rear cassette After your second chain is worn and ready to be replaced, you should also replace your rear cassette (if you use a standard cassette-derailleur arrangement, if not disregard this advice) and also inspect the condition of the front chainring teeth for excessive wear and replace if necessary.
Getting to the actual point of this article, I strongly recommend that while you are in the process of removing and replacing your chain, you first remove your rear wheel, remove the cassette (using a cassette removal tool and a chain whip) and give the cassette a thorough clean BEFORE you install the new chain. I also suggest that while you have the cassette and rear wheel off, you also give the rear derailleur a good degrease and scrub to remove all the dirty gunk built up on it, and then apply some fresh oil on the moving parts and jockey wheels (also inspect the condition of the jockey wheel teeth and replace if necessary). The reason for this is that, due to the location and way it works, the cassette and rear derailleur are usually going to be covered in dirty, greasy, oily residue. This residue is usually full of sand and will cause further damage to your new chain and existing components. Additionally, the gunk will also make the drivetrain less smooth and require more energy to pedal.
There are a variety of ways that people clean their chain and cassette components, some prefer to soak in a pan of solvent fluid, including citrus degreaser, mineral turpentine, or diesel/ petrol fuel (gasoline) etc. However, I have always found these methods to be unpleasant and unfriendly to the environment. Instead I have found that soaking the cassette in a small tub of hot, soapy water for 10 minutes and then using an toothbrush to scrub off the gunk and a rag to polish and dry works wonders (when you’re done with the toothbrush clean it very carefully before using it again to brush your teeth*). In order to be more environmentally friendly I suggest that you use a grey-water safe, salt-free detergent (like Earth Choice). This cleaning process will be far easier and safer if you use a eco-friendly, plant based, non-toxic lubricant such as Green Oil.
Unfortunately I didn’t think to take any before photos, as I wasn’t expecting my results to be so good. But if I could take the liberty of conjuring an image of what the cassette did look like, just imagine it being completely covered in a layer of dark grey residue with sand and bits of debris stuck in it from 12 months of commuting since it was last cleaned. After soaking it for 10 minutes in the hot, soapy water (extra concentrated) and then scrubbing for a few minutes I was amazed to see how quickly it cleaned up. After scrubbing, I then rinsed it twice in hot water and left it outside in the sun to dry thoroughly before reinstalling to the wheel and adding the new chain. While I was waiting for it to dry (it took about 15 minutes) I went and gave the derailleur a good scrub as well with the hot soapy water and toothbrush.
Here it is, after being cleaned and drying outside:
Given how easy and quick this job was, I would recommend that it be done every 12 months / 4,000-5,000 km if you are commuting through the year. Of course, there are many variables here, including weather, terrain, and conditions you ride in, how you treat your bike etc.
People who ride on sandy trails or through water will find that cleaning will need to be more frequent. If you are only riding in clear, dry conditions and look at your bike you won’t need to do it as frequently.
The rule of thumb here is to inspect your cassette and derailleur and if it looks particularly dirty, gunky and full of sand, then do yourself and your bike a favour and give it a thorough clean. You won’t regret it.
Happy and smooth cycling
*This is a joke. I didn’t think I would have to point it out, but some people take things too literally.