chain scrubbing

[gbb]

My advice, just clean it with a rag and oil it, then wipe off excess...
When I seriously rode and commuted all weathers I tried a few different regimes, from removing chain, blasting off debris with high pressure airline,(then you really see dirt coming out) soaking in oil, drip drying erx etc...to trying solvents, to try8ng other regimes...and because I recorded chain life in miles, i realised each actually made little difference at all, chains didnt suddenly double moleage life. It was interesting while I tried it all...but all a bit.pointless really.
Wipe, oil, wipe.

 

[silva]

Transmission force pushes anything including oil wax and sand away from the mating surfaces. How can wax serve as a lubricator if it's too viscous to return?
It can merely function as a kinda sealing to keep dirt out.
Or repel water, as to prevent internal corrosion.
A sealing ALSO keep worn off particles inside.
Much like happens in O-ring etc sealed chains.
Only mechanical vibrations have a chance to dislodge sand, ex ultrasonic cleaner, if density differs enough from the liquid in which it vibrates.

Water dissolves material, that can then be flushed out.
But chains internal dries alot less quick than externals, risking an invisible series (usually gravity downwards) of internal brown spots.
That then when riding, get rubbed off to dust, that is, the chain becomes longer just like due to material lost by wear.

So, the easiest and cheapest way to get dirt out of a chains internals, is to put LOTSA oil on it, then go for a ride.
Pedaling, centrifugal and gravity forces will push dirt away, facilitated by the oil, to then drip off with it.
Eventually, if needed, stop, and replenish the oil.
This is what happens in all combustion engine vehicles, the only difference is that the oil ends on street, just like the "total loss" lubrication of motorcycles in their early days.
But this case is occasional and involves a tiny fraction of the oil, so nobody will bother, just don't put the oil on when the bike stands on some cosmetic crap.

 

[presta]

Transmission force pushes anything including oil wax and sand away from the mating surfaces.

Why lubricants stay put under pressure, (from Copilot):

Hydrodynamic wedge effect

• fluid wedge formation: When surfaces move relative to each other, they drag the lubricant into a narrowing gap, creating a pressure buildup that pushes the surfaces apart rather than letting the fluid escape.
• self‑pressurizing film: The faster the surfaces move, the more pressure the fluid generates, often far exceeding the external load.

Viscosity and shear behavior

• resistance to flow: Lubricants have viscosity, meaning they resist being squeezed out like honey between two plates.
• shear‑thinning or thickening: Some lubricants change viscosity under stress, becoming thicker when squeezed, which helps them stay in place.

Surface roughness and micro‑pockets

• microscopic surface valleys: Even polished metal has tiny peaks and valleys. Lubricant gets trapped in these pockets, forming a stable film.
• asperity separation: The fluid film prevents the highest surface peaks from touching, reducing wear.

Boundary and chemical films

• adsorbed molecular layers: Many lubricants contain additives that chemically bond to the surface, forming a super‑thin protective layer that pressure cannot squeeze out.
• extreme‑pressure additives: Under very high loads, these additives react to form solid films (like sulfides or phosphates) that stay put even when the fluid is displaced.

Geometry and confinement

• sealed or narrow gaps: In bearings, gears, and pistons, the geometry physically traps the lubricant.
• capillary and viscous forces: In tight spaces, these forces can be stronger than the squeezing pressure.

 

[silva]

If one can see between rollers and plates and between inner plates and outer plates, how can pressure build up?
There is nothing tight in a bicycles roller chain.
That's why they invented sealed roller chains: to keep dirt out and lubricant in, as to have an acceptable life time and acceptable amount of work.
Without sealing, grease/wax just gets pushed away from where it's needed to lubricate, to then stay away, while oils viscosity is low enough to return due to gravity and forces other than the riders.

 

[Yellow Saddle]

Why lubricants stay put under pressure, (from Copilot):

Hydrodynamic wedge effect

• fluid wedge formation: When surfaces move relative to each other, they drag the lubricant into a narrowing gap, creating a pressure buildup that pushes the surfaces apart rather than letting the fluid escape.
• self‑pressurizing film: The faster the surfaces move, the more pressure the fluid generates, often far exceeding the external load.

Viscosity and shear behavior

• resistance to flow: Lubricants have viscosity, meaning they resist being squeezed out like honey between two plates.
• shear‑thinning or thickening: Some lubricants change viscosity under stress, becoming thicker when squeezed, which helps them stay in place.

Surface roughness and micro‑pockets

• microscopic surface valleys: Even polished metal has tiny peaks and valleys. Lubricant gets trapped in these pockets, forming a stable film.
• asperity separation: The fluid film prevents the highest surface peaks from touching, reducing wear.

Boundary and chemical films

• adsorbed molecular layers: Many lubricants contain additives that chemically bond to the surface, forming a super‑thin protective layer that pressure cannot squeeze out.
• extreme‑pressure additives: Under very high loads, these additives react to form solid films (like sulfides or phosphates) that stay put even when the fluid is displaced.

Geometry and confinement

• sealed or narrow gaps: In bearings, gears, and pistons, the geometry physically traps the lubricant.
• capillary and viscous forces: In tight spaces, these forces can be stronger than the squeezing pressure.

And?