How to Clean a Bicycle Chain

Steps

1. Measure first, clean second: a chain that has stretched past its limit is not worth cleaning. As it wears it grinds new shapes into the teeth of the cassette and chainrings, and those cost far more to replace than the chain does. The threshold depends on your drivetrain, so check how many sprockets are on the rear wheel before you read the gauge.
2. 1

   Check the chain for wear

   Before you clean anything, measure how far the chain has stretched. A worn chain chews up the cassette and chainrings, so replace it rather than clean it. On 11 and 12-speed drivetrains, 0.5% elongation is the point to replace. On older 8 to 10-speed chains, the limit is 0.75%.

3. 2

   Scrub the chain with a chain cleaner

   If the chain still has life in it, clean it with a chain-cleaning device, also called a chain scrubber. Fill the device with degreaser up to the fill line. Clip it onto the lower run of the chain and backpedal. The brushes inside rotate and scrub all four sides of the chain at once.

4. Why the tool beats a quick wipe: a chain has four faces, and the dirt that matters sits where the rollers turn. The brushes inside the scrubber press against all four sides as the chain passes through. Backpedal steadily rather than fast, and let the tool do the work.
5. 3

   Drip lube into every roller

   Once the chain is clean, add lube one drop at a time, one drop per roller. Backpedal slowly as you go. Aim each drop into the rollers, not onto the flat outer side plates.

6. 4

   Wipe off the excess

   After lubricating, wipe the outside of the chain down. Lube sitting on the outer plates does no lubricating at all. It only collects dirt and grit.

7. A light chain is a clean chain: fresh lube on the outside looks reassuring, but it is doing nothing useful there. It sits on the surface and traps every bit of road dust and grit that lands on it. The oil you want is already inside the rollers, where you dripped it.
8. 5

   Keep the chain clean and lubricated

   Make this part of your normal routine. A clean, lubricated chain runs with less friction and wears more slowly. You get smoother shifting and longer life from the chain, the cassette and the chainrings, which means fewer expensive drivetrain replacements.