[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.

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