[KiwiMike]

I’m just going to leave this here…

The claim Fairy Liquid Will Eat Your Bike due to ‘salt’ is an urban myth that needs to die, before anyone wastes any more cash on ‘bike-specific cleaners’.

I have washed all of our many bikes using Fairy liquid or Ecover for decades. I’ve never found any evidence of corrosion, paint, laquer or decal wear, or any sign of anything. I regularly service forks and bearings, swapping a lot of gear, and everything has always been fine.

Here’s far too much info below – long story short, Fairy liquid in 5L of hot water has a borderline-homeopathic amount of salt, it’s fine to use on a bike.

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The honest answer is that neither Fairy nor Ecover publicly disclose the actual sodium chloride concentration in the consumer products I could find. The safety data sheets list hazardous ingredients above reporting thresholds, but sodium chloride is not reported for either product.

However, we can put some realistic bounds on it.

Fairy Original

The SDS lists:
Sodium laureth sulfate: 20-30%

Lauramine oxide: 5-10%

Alcohol: 1-5%


No sodium chloride is declared.

In detergent formulations, sodium chloride is commonly used as a viscosity modifier (thickener) and is typically present at around 0.5-3%, sometimes lower. The absence of declaration suggests it is either not present or present at a low concentration that does not require reporting. This range is an informed formulation estimate, not a value stated by Fairy.

Ecover

The Ecover ingredient information lists:
Sodium lauryl sulfate

Lauryl glucoside

Cocamidopropyl betaine

Alcohol

Lactic acid

Sodium octyl sulphate


Again, no sodium chloride is listed.

Ecover’s formulations tend to rely more heavily on plant-derived surfactants and may use little or no salt for thickening, but I could not find a published concentration.

What does this mean for bike washing?

Let’s assume a worst-case 3% salt content in Fairy.

If you add:
10 mL Fairy to a 5-litre bucket


Then salt introduced would be approximately:
10 mL × 3% ≈ 0.3 g salt


Distributed through 5 L water


≈ 60 mg/L salt


For comparison:
Typical seawater: ~35,000 mg/L


Lightly salted winter road spray: often hundreds to thousands of mg/L


The wash bucket above: ~60 mg/L


So even under a pessimistic assumption, the salt concentration is hundreds to thousands of times lower than the salt exposure your bike gets from winter roads.
From a corrosion perspective, the quantity of salt introduced by washing-up liquid is essentially negligible compared with:
Riding on salted roads

Coastal spray

Leaving winter grime on the bike


Therefore my practical conclusion remains:
✅ Fairy or Ecover in a wash bucket is extremely unlikely to contribute any measurable corrosion risk.
✅ The important thing is rinsing and drying afterwards.
✅ Winter road salt is the real enemy, not washing-up liquid.

Topic

[arowland]

To be fair to seawater and winter roads (even seawater has feelings (maybe)), though their salt content is higher than Fairy Liquid, they don’t also contain detergents to wash off any protection you might have, e.g. the oil on your chain. It’s the combination that is what makes people wary of it.
But I have used washing up liquid for many years without problem — just rinse off thoroughly and oil / lube / grease up your vulnerable components. And always wash winter salt off as soon as possible. Just common sense.

[Daclu Trelub]

I’ve found Fairy to be corrosion free, but it’s the cheap no-name corner-shop varieties that have loads of salt in them.
I’ve known this for decades, after speaking to a small businessman who used to buy 205L barrels of detergent from ICI and dilute it by some ludicrous factor, adding loads of salt to thicken it up, and bottled it for sale to corner-shop supply chains.
Those are the ones to never use when cleaning your bike, car, motorcycle, armoured car, etc.

[Cayo]

*corrosion* (edit doesn’t seem to work on my phone).

[Cayo]

I repeat a tip I got from a Garmin Sharp mechanic at the Giro in Northern Ireland. He recommended a drop of Fairy mixed into the Morgan Blue degreaser they used at the time.

Worked a treat, and I doubt they’d have risked that if corossion was an issue, even on their parts budget. I’ve used that method ever since, no problems.

[KiwiMike]

Yeah, me above the lines, AI below (with my prompting), so presume way! Life’s too short etc 🙂

[KiwiMike]

Crikey – I suspect if you followed the guidance of that pay-to-view outfit there would be very few brands left to use. Obvs I wasn’t making the statement in the full round of ethics – just that it’s fine to use from the POV of it won’t dissolve your bike anytime soon.

[quiff]

I don’t subscribe, so can’t see the underlying detail – but I assume Ecover being bought by SC Johnson contributes quite a lot to its poor score, as it at least professes to be quite good on ingredients.

[mdavidford]

Fairy Liquid may not damage your bike, but ‘Fairy Liquid is FINE’ is a somewhat more contentious claim:
https://www.ethicalconsumer.org/home-garden/shopping-guide/ethical-washing-up-liquid

Of course, your bike-specific cleaner of choice might not do much better if it was assessed (though it could hardly do worse).

Even Ecover does surprisingly poorly there, but there are others you could upgrade to.

[quiff]

I took the tramlines to be separating Mike’s words (above) from AI research (below). The emoji bullets and some of the phrasing smacked of AI to me, unlike Mike’s turns of phrase (I enjoyed “borderline-homeopathic”). But I’m sure Mike will correct me if wrong! Incidentally, my bottle of Ecover does list sodium chloride on the bottle, but no quantities. And it suggests dosing (for dishes) at just 3ml per 5L.

[ktache]

Does it resemble AI, I assumed it was from the fair hand of kiwimike, presumably reading off bottles he had in his kitchen. I for one wouldn’t have dared to presume otherwise.

[quiff]

I don’t disagree, but I feel the AI (presumably) is somewhat missing the point when it says:

“So even under a pessimistic assumption, the salt concentration is hundreds to thousands of times lower than the salt exposure your bike gets from winter roads.”

Well yes, but I wasn’t planning to wash my bike with brine, so the question is really how it compares to other cleaners. That said, I’m bad for leaving winter grime on the bike, so maybe Fairy > Winter Grime is a fair comparison.

[hawkinspeter]

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[hawkinspeter]

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[hawkinspeter]

That’s all well and good, but what about the cheap Aldi washing up liquid?

[KiwiMike]

Dude. I’ve been washing bikes with this stuff for decades. As a professional mechanic I also do things like swap all my own bearings – hub, headset and pivots. Typically after a few years, depending on mileage. Every bearing I’ve ever swapped has always been full of grease – just developed play due to wear, maybe contaminated by years of eventual dirt ingress as the rubber seals perish. So if Fairy Liquid is supposed to dissolve bearing grease, it’s pretty crap at it.

Shout all you like in all caps, doesn’t change the fact a bike washed with the like of Fairy liquid then rinsed off is in absolutely no danger of the sort of damage you’d like to portray.

There is a great deal of difference chemically between a dedicated degreaser and Fairy liquid / bike cleaner. But a bike cleaner includes ‘surfectants’ – ahem:

Looking at the Safety Data Sheets (SDS) for Muc-Off Bike Cleaner, one of the main surfactants is Alcohols, C12-14, ethoxylated, sulfates, sodium salts

CAS: 68891-38-3
Typically present at 1-10%
This is a modern anionic surfactant very similar in function to the surfactants used in dishwashing liquids.

As per the post, your bike is at far more risk of harm from moisture-bearing road salt, that is then left to dry. And for many people, the use of degreasers on the drivetrain. They are genuinely terrible for bearings and should only ever be used on components once removed from the bike.

[Author]

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