What you are checking for
The chain and gears turn your effort into movement, and they do it in a dirty, high-friction place. Problems tend to build slowly: a chain gets dry, a cable stretches, a gear starts hesitating. A short check before you ride catches many of these while they are still small. It also reduces the chance of a chain dropping or jamming at a bad moment, such as while pulling away at a junction.
This is general guidance. Drivetrains differ, and your manufacturer’s instructions or a bike shop should guide any adjustment or repair.
Look first
With the bike upright, ideally on a stand or held steady, look along the chain.
- Colour and surface. A chain covered in orange rust, or dry and grey, needs attention. A chain thick with black grime is also not ideal, since dirt wears parts faster.
- Stiff links. Turn the pedals slowly backwards and watch the chain run through the rear mech. A link that kinks or does not flex smoothly can cause a skip or sudden noise.
- Damaged links or missing pieces. Look for bent plates or anything that looks out of line.
- Teeth. Check the chainrings and sprockets. Hooked, sharp or badly worn teeth can affect how the chain sits.
You can also check the chain for general wear. Our explanation of how to tell when a chain is worn covers the idea of chain wear and when a replacement is sensible. A worn chain can damage other parts, so it is worth taking seriously, but measuring it properly needs the right tool or a shop visit.
Listen and feel
Pedal gently and listen. A smooth, quiet drivetrain is a good sign. Squeaks often mean the chain is dry, grinding can mean dirt or wear, and clicking at regular intervals can point to a stiff link or a damaged tooth. Keep in mind that noise can have several causes, so treat it as a clue rather than a diagnosis.
If the chain is dry or dirty, cleaning and lubricating it is a straightforward job; see our guide to chain cleaning for the steps. Use a lubricant made for bike chains and wipe off the excess.
Test every gear
Shifting is easier to test while the bike is held off the ground or rolling slowly on flat, traffic-free ground. Change gears while pedalling lightly, since most drivetrains do not like shifting under heavy load.
- Start in the middle of the range and shift up one gear at a time at the back until you reach the end, then back down.
- Each shift should happen promptly and quietly, with the chain settling on a gear without rattling.
- If you have more than one chainring at the front, shift between them too, and then check a few gear combinations.
- Check that the chain does not rub the front derailleur cage in any gear you plan to use.
On hub gears, the process is similar, though the signs differ; follow the manufacturer’s guidance.
Common problems and what they suggest
- Hesitating or slow shifts. Cables may be stretched, dirty or sticky, or the shifter needs adjustment.
- Skipping under load. Often a worn chain, worn sprockets or a stiff link. Our guide on why your gears skip goes through the usual causes.
- Chain dropping off. May relate to limit screws, a bent hanger or a worn component.
- Grinding in some combinations. This can be a sign of cross-chaining, where the chain runs at an extreme angle. Our topic on cross-chaining explains why it is best avoided.
- Rear mech swinging or sloppy. May be a bent or loose part. Stop and have it checked.
If you drop the bike on its drivetrain side, or a stick or object gets into the gears, a bent derailleur hanger or mech is possible. Do not force the gears. A shop can usually diagnose it quickly.
What to do if something feels wrong
For small issues, such as a dry chain, cleaning and lubricating may be enough. For others, particularly skipping, a damaged link or poor shifting that does not improve, do not ride hard and book a shop visit. A chain that breaks under load can cause a fall, and a gear that slips unexpectedly can put you off balance. If you need to learn what to do after a break on the road, our topic on a broken bike chain fix covers roadside options, and carrying a few basic items helps.
Keeping it simple
You do not need to dismantle anything for this check. A look, a slow turn of the pedals and a test through the gears are enough for most rides. If gear changes are sticky, a regular service interval is sensible, as set out in how often to service a bike. The aim is to know what normal sounds and feels like, so that anything unusual stands out. If you are ever unsure about a repair, leave it to a bike shop.