TL;DR
A dirty chain is a grinding paste, and it wears a drivetrain out several times faster than a clean one. Degrease the chain and cassette, scrub with a stiff brush, rinse, dry the chain completely, then put one drop of lube on every link and wipe the outside dry. Do it every few hundred miles, or any time the chain looks black and gritty.
Why a dirty chain costs real money
Chain lube is sticky on purpose. That stickiness catches road dust, trail grit, and brake dust, and the mixture turns into a fine abrasive slurry.
That slurry sits exactly where the chain's rollers and pins move against each other. Every pedal stroke grinds a little metal away, the chain stretches, and a stretched chain starts chewing the teeth on the cassette and chainrings.
Chains are cheap. Cassettes and chainrings are not. Cleaning is the cheapest maintenance on a bicycle by a wide margin.
How do you clean a bike chain?
Shift to the smallest cog, apply a bike-specific degreaser to the chain, and pedal backward while scrubbing the links with a stiff brush. Scrub the cassette and chainrings the same way, rinse with low-pressure water, dry the chain fully with a rag, then relube.
What you need
- A bike-specific degreaser, or a citrus degreaser diluted per its label
- A stiff-bristle brush and a narrow brush for tight spaces
- Rags you do not care about
- A bucket of soapy water and a low-pressure rinse
- Chain lube matched to your riding conditions
- A stand, or something to hold the bike upright with the rear wheel free
Skip the household solvents. Gasoline, paint thinner, and other flammable solvents are never appropriate for this job. They are fire and vapor hazards in a garage, they strip factory grease out of sealed bearings, and they attack rubber seals and some frame finishes.
The step-by-step
1. Shift into the smallest rear cog. This moves the chain away from the spokes and gives you room to work.
2. Apply degreaser to the chain. Work along the whole loop while pedaling backward by hand. Let it sit for the time the label says, usually a minute or two, so it can break the grease down.
3. Scrub the chain. Pedal backward and hold a stiff brush against the chain from below, then from the side. Do both sides. A chain-scrubber tool that clamps over the chain does the same job with less mess.
4. Move to the cassette. Run a narrow brush between the cogs. A rag pulled back and forth through each gap like dental floss clears the packed grime that brushes miss.
5. Do the chainrings and the derailleur pulleys. The two small jockey wheels on the rear derailleur collect a black paste that nobody thinks to clean. Scrape it off with a small brush or a plastic pick.
6. Rinse gently. A hose on low flow or a bucket and sponge. Never a pressure washer, and never aim water at the hubs, bottom bracket, or headset -- covered in how to wash a bike frame without wrecking the bearings.
7. Dry the chain completely. Run it through a clean rag several times. Lube will not stick to a wet chain, and water left in the rollers starts surface rust within hours.
How often should you clean a bike chain?
Every 100 to 300 miles for dry-road riding, and after every wet or muddy ride. The real test is simpler: if you run a clean rag along the chain and it comes back black and gritty, it is time. A chain that squeaks is already overdue.
Relubing: the part most people do wrong
Lube belongs inside the rollers, not on the outside of the chain. Anything on the outside only collects dirt.
Put one drop on each roller while slowly pedaling backward, all the way around the loop. Let it soak in for a few minutes. Then take a clean rag, wrap it around the chain, and pedal backward several full rotations to wipe every bit of surface lube off.
The chain should look almost dry when you are done. That is correct.
Wet lube is thicker and stays put through rain, which matters through a Willamette Valley winter. It also grabs more dirt, so it needs cleaning more often.
Dry lube goes on wet, dries to a wax-like film, and holds far less grit. It works well in summer and washes off quickly in rain.
Wax-based systems run the cleanest of all but require a fully stripped chain to start.
Do not use general-purpose penetrating spray as chain lube. It is a water displacer and a solvent, not a lubricant, and it thins out the lube already in the chain.
Cleaning the cassette, chainrings, and pulleys properly
The chain is only half the drivetrain. If you clean the chain and put it back onto filthy cogs, it picks the grime straight back up.
Work the brush between every cog gap until you see bare metal. Check the chainring teeth for a hooked or shark-fin shape, which means wear rather than dirt.
The jockey wheels usually need the most attention and get the least. Pick the packed gunk out from between the teeth and around the hub of each wheel.
Mistakes that shorten a drivetrain's life
- Pressure washing. It forces water and grit past hub, bottom bracket, and pivot seals. Damage shows up weeks later as grinding bearings.
- Lubing over a dirty chain. This turns grit into a paste and seals it in.
- Leaving the chain wet. Surface rust forms fast on a bare, degreased chain.
- Over-lubing. Excess lube on the outside is a dirt magnet, nothing more.
- Using flammable solvents. A fire hazard, and hard on seals and finishes.
- Storing a wet bike indoors without drying it. The same rule that applies to a muddy kids bike in cleaning a kids bike after muddy rides.
When the chain is past cleaning
Chains stretch as the pins and rollers wear. A chain checker tool costs very little and tells you in seconds.
Replace the chain at the wear point the tool marks, and the cassette lasts far longer. Ride a worn chain long enough and the cassette wears to match it, at which point both have to be replaced together.
Cleaning is what buys the extra miles between replacements.
Source: Park Tool repair and maintenance reference
Where the garage grime ends up
A drivetrain cleaning session leaves black degreaser residue on the floor, on rags, and on whatever the bike leaned against.
Work over cardboard or a drip tray. Let dirty rags dry flat and spread out before you bin them, never wadded in a pile. Check local rules for disposing of used degreaser rather than pouring it down a drain.
The rest of the garage benefits from the same habits described in our guide to cleaning outdoor gear and equipment.
FAQ
Can you clean a bike chain without taking it off?
Yes, and for most riders that is the better option. A chain-scrubber tool or a stiff brush plus degreaser cleans the chain in place while you pedal backward. Removing the chain gives a deeper clean, but on a modern chain it means a new quick link or pin each time.
What can I use instead of bike degreaser?
Dish soap and hot water handles light grime, and a diluted citrus degreaser handles heavy build-up. Do not use gasoline, paint thinner, or any flammable solvent. They are a serious fire risk in a closed garage, and they strip grease out of sealed bearings and damage rubber seals.
How do I know when my chain needs lube?
Listen and look. A chain that squeaks or chirps under load is dry, and a chain that looks dull grey with no sheen inside the rollers is dry. After rain, assume the lube has washed out. A properly lubed chain is quiet and looks almost clean on the outside.
Is it bad to pressure wash a bicycle?
Yes. Pressure washers drive water and grit past the seals in the hubs, bottom bracket, headset, and suspension pivots, washing out the grease those bearings depend on. The bike looks clean and the bearings fail a month later. Use a bucket, a soft brush, and low-pressure rinsing instead.
How often should I replace my bike chain?
When a chain checker shows the wear limit, which for most riders is somewhere between 2,000 and 3,000 miles depending on conditions and cleaning habits. Replacing at that point protects the cassette and chainrings. Riding a worn chain past the limit forces a much more expensive drivetrain replacement.
Should I clean the cassette every time I clean the chain?
Clean it every time you do a full degrease. A clean chain on a dirty cassette picks the grime straight back up within a few miles. Between full cleans, a quick pass with a rag between the cogs is usually enough to keep the build-up down.
A bike cleaned in the garage tends to leave the garage grimy. If keeping the whole house up is the harder job, get a quote or read more about house cleaning services.