What is the best way to remove rust from bike components?

If you have ever left a bike unattended for a prolonged period of time, especially if it is stored outside, you have more than likely found that certain components have become rusty. Fortunately, all is not lost as in most cases, a rusty chain or cassette can be restored to its former shiny self with a bit of elbow grease and the helping hand of some chemical cleaners.

To try and offer a solution to the problem many of us have faced, Alex Paton aimed to find out exactly which method works best by putting specific rust cleaners up against a degreaser, baking soda and even Coca-Cola.

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For this test Alex is using a rusty chain, however the same principles apply to chainrings, cassettes, derailleurs or any other rusty component. The first step is always to remove the component from the bike so you can work on it in isolation.

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How do four very different products perform when it comes to cleaning a rusty chain?

The method

To ensure all the options are tested equally Alex is going to break the same rusty chain into four equal parts and place them in each of the chemical cleaners for one hour.

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At the end of the hour, each chain is agitated with a wire brush to help lift off the surface rust. Each chain is then put in a ziplock bag along with the cleaning agent and left. Using the ziplock bag ensures that each section of the chain gets fully submerged, ensuring the comparability of the results.

What is rust?

Rust is a byproduct of the oxidation process in metal. When iron comes into contact with a combination of oxygen and water, the corrosive process that takes place creates rust.

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Rust is a product of the oxygenation process of metals containing iron

Due to the fact that iron needs to be present in the metal, this means that both aluminium and titanium components do not suffer from rust. However, aluminium can still suffer from corrosion, most commonly from salt water.

Using Coca-Cola as a rust treatment

This may be a surprising inclusion in this test, but Coca-Cola is an odd hack that some people claim can be used to remove rust. But does it work, or is it just a myth?

After an hour of soaking, the chain that had been bathed in Coca-Cola came out looking much the same as it went in. With a little bit of agitation with a small pick, none of the rust easily lifted off the chain either. With the wire brush, a lot of the surface rust did start to work free, however Alex does point out that it seemed more likely that it was the action of the wire brush that facilitated this rather than anything he could attribute to the Coca-Cola.

Is degreaser any better at removing rust?

As you might expect, the degreaser did not magically clean off the rust from the chain. The chemical properties of a degreaser as specifically formulated around breaking down - as the name suggests - greases and oils. After an hour of being submerged, the chain came out looking equally as rusty as when it first went in.

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Degreaser is specifically formulated to break down oils and greases rather than remove corrosion

Once again with the use of a wire brush, the worst of the rust did start to come away from the chain but once again, this did appear to be the work of the brush and the brush alone.

Can baking soda remove rust from a bike chain?

This is a home remedy that Alex thought could have what it takes to lift the rust off the chain. However, even after an hour of soaking it came out looking identical to when it went in. Once it had been removed from the bath of baking soda, Alex thought that the presence of some of the powder on the chain would act as an abrasive and help compliment the brushing to remove the rust. After brushing the chain with the wire brush, though, this theory was all but disproved by its ineffectiveness.

How well did the dedicated rust removal treatment fare?

The rust remover had a lot to live up to, being the only product in this test that actually claims to be able to clean rusted metal products and restore them to what they once were. As the chain was removed from the bag it was clear that the rust cleaner itself was going to take a bit of encouragement to come away from the chain.

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The dedicated rust remover did indeed come out on top as was to be expected

Bathing the chain and rust cleaner in water helped to remove the chemical. Towelling the chain to dry it off helped remove a great deal of the surface rust with only a few small areas of more persistent rust remaining.

What is the final verdict?

With all the products tested it is time to rank them in order from worst to best. In last place is the degreaser, ultimately it is just the wrong product for the job so it hardly comes as a surprise that it was underwhelming. In third place is the baking soda, as any rust that was removed from the chain that was soaked in the baking soda was a result of the brushing rather than the soaking itself.

In the runner-up spot is Coca-Cola. Although it didn’t remove the rust without some agitation from a wire brush, it did work well in collaboration with the brushing. As you might have expected, the winner from this test goes to the rust remover. This did take some work with a brush too, however it did clean up the best out of all of the treated chains and with the least amount of additional effort.

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Something to bear in mind is that the dedicated rust remover costs around £/$/€13 whereas a can of Coca-Cola costs a more modest £/$/€1 for a can. When you factor that in, using a dedicated rust remover might not seem like the natural choice after all.

With all of this being said, if something on your bike is incredibly rusty it might be a safer bet to look at replacing it. Surface rust isn’t an issue and can be cleaned away, but if the rust looks to be more substantial it is not worth risking your safety by using parts if you are unsure about their integrity.

Do you have any other tips when it comes to removing corrosion from bike components? Let us know in the comments section below.

Alex Paton

GCN Tech Presenter

Impressive sprinter - quite possibly the fastest member of the GCN team