Washing-up liquid on a bicycle

Does it work?

Does not work

Refuted as stated by the trade's own documentation, which names the product the warning prohibits. Recorded because it is a good example of a rule that is right about a mechanism and wrong about a conclusion — the soap really does remove lubricant, and the documented procedure handles that by putting the lubricant back rather than by avoiding the soap.

This is a verdict on whether the technique is effective. Whether it is safe on a particular surface is a separate question, answered below.

Why it works

The warning's mechanism is that a degreasing detergent strips lubrication from chain, bearings and pivots, and that residues promote corrosion. The first half is accurate and is precisely what the documented procedure relies on for the chain. The second is where it overreaches: a rinsed and dried frame carries no residue, and sealed bearings are not reached by a soapy wash at the pressures the documentation permits. The risk that is real — solvent entering a bearing — belongs to the degreaser stage rather than the soap.

Background

This is the rare case where the folk warning is stricter than the trade documentation. Park Tool's own repair article on washing a bicycle lists the materials required and states plainly that a quality dish washing soap is acceptable, then instructs filling the buckets with hot water and mixing in a biodegradable dishwashing liquid or similar soap — with the same reasoning anybody would use at a sink, that warm water cleans better. It is used on the frame, the wheels and, in the second stage of the drivetrain clean, on the chain itself. The kernel of truth in the warning is real but misplaced. A detergent DOES remove lubricant, which is exactly why the documentation makes re-lubrication a mandatory step rather than an optional one: run the chain through a clean dry rag and apply one drop of lubricant per link. The failure people attribute to the soap is a failure to complete the procedure. Two genuine cautions survive. Detergent left unrinsed leaves a residue, which is why hand-drying with a towel is recommended so that unrinsed soap is caught. And nothing about the soap protects bearings from solvent, which is a separate stage with its own precaution.

Conditions

• Low-pressure rinsing only
• Chain re-lubricated afterwards
• Frame dried by hand to catch unrinsed soap

What it does not do

• It is a detergent, so it removes lubricant and the chain must be re-lubricated afterwards.
• Unrinsed residue attracts soil and can leave a film on the finish.
• It does nothing for a bonded chain deposit, which needs the solvent stage first.

What to use instead

• Bicycle degreaser — A solvent aimed at a drivetrain, and the reason it needs its own record is where it must not go: bearings, and the lubrication it strips by design.
• Two-stage degreasing — A solvent pass followed by a detergent pass. Each finishes what the other cannot, and the trade documentation says so in one sentence.
• Re-lubrication — The step after degreasing, and it is not optional. Cleaning a mechanism removes the lubricant deliberately, and stopping there is worse than not cleaning it.
• Bicycle chain — The dirtiest component on the machine and the one that must be lubricated immediately after it is cleaned. Cleaning it and stopping there causes wear.