The chain is the simplest part of the drivetrain and the one most often neglected. A dry chain wears quickly, a tight chain damages bearings and a worn chain can derail. The job takes minutes and prevents expensive repairs.
At a glance
| Task | What to check | Warning sign |
|---|---|---|
| Clean | Dirt, grit and old lubricant | Dry, gritty or rusty links |
| Lubricate | Inside of the chain run | Noise and rapid wear |
| Slack | Manual range at the midpoint | Too tight or too loose |
| Alignment | Axle marks or a straight edge | Wheel cocked in the swingarm |
| Wear | Sprocket teeth and chain lift | Hooked teeth or tight spots |
Tools and products
You need a chain brush, a cleaner suitable for the chain type, a rag, the specified chain lubricant, a rear stand or centre stand, and a ruler or the bike's adjustment marks. A torque wrench is useful for the axle nut.
Use a cleaner that is safe for O-ring and X-ring chains. Kerosene is a traditional choice for many chains; a dedicated chain cleaner is convenient. Do not use petrol, brake cleaner or a high-pressure washer directly on the chain.
Precautions
Switch off the engine and keep hands away from the sprocket and the chain run. Never clean a chain with the engine running and the bike in gear. A rag caught in the sprocket can pull a finger in.
Work on a stable stand. Clean the chain away from the brake disc and pads; oil or cleaner on the friction surfaces reduces braking. Wipe up spills immediately.
Clean and lubricate
Brush the chain from the inside out, rotating the wheel by hand. Apply the cleaner to the brush or the chain, not to the brake disc. Wipe away the loosened dirt with a rag. For a heavily soiled chain, repeat the process.
Let the cleaner evaporate, then apply lubricant to the inside of the chain run so centrifugal force carries it outward. Wipe off the excess. A chain that is dripping attracts dirt and flings oil onto the tyre and the rim.
Adjust the slack
Check the slack at the midpoint of the lower run, with the bike on its side stand or centre stand as the manual specifies. Measure against the manual's range. Adjust at the rear axle according to the bike's design, keeping the wheel aligned.
Tighten the axle nut to the specified torque and recheck the slack. A chain that is too tight loads the output shaft bearing and the rear suspension. A chain that is too loose can jump the sprocket or slap the swingarm.
Inspect for wear
Check the sprocket teeth for a hooked or pointed profile. Pull the chain away from the rear sprocket at the three o'clock position; if it lifts significantly, the chain is worn. A chain with tight spots or seized links should be replaced.
Replace the chain and sprockets as a set when they are worn together. A new chain on worn sprockets wears quickly and can skip. Use the correct pitch and length for the model.
When to book the workshop
Book a workshop if the axle nut is seized, the wheel alignment is uncertain, the sprocket is worn or the chain has a tight spot. A chain failure at speed can lock the rear wheel or damage the engine cases.
If the chain needs adjustment every few rides, it is worn or the sprockets are worn. Do not keep tightening a stretched chain; replace the set.
The bottom line
Clean the chain, lubricate it, adjust the slack and inspect the sprockets. If the chain needs constant adjustment or the teeth are hooked, replace the set. A chain failure is not a roadside inconvenience; it can lock the rear wheel.IndoBikes workshop
Checklist
- Switch off the engine and support the bike securely.
- Clean the chain with a suitable brush and cleaner.
- Keep cleaner and oil off the brake disc and pads.
- Apply lubricant to the inside of the chain run.
- Wipe off excess lubricant.
- Measure slack at the specified point.
- Adjust and align the rear wheel.
- Torque the axle nut and recheck.
- Inspect sprocket teeth and replace the set if worn.
Questions
Can I use WD-40 to lubricate a chain?
WD-40 is a water displacer, not a chain lubricant. It can help clean a non-O-ring chain, but it does not provide the film a chain needs. Use a proper chain lubricant.
How often should I lubricate the chain?
After rain, after washing, and at the interval in the manual. In dusty or wet conditions, check it more often. A dry chain wears quickly.
Do I need to replace the sprockets with the chain?
If the sprockets are hooked or worn, yes. A new chain on worn sprockets wears quickly and may skip.
