What to do if…
your bicycle chain snaps or jams and you cannot pedal

What to do now

1. Stabilise and slow down. Stop pedalling, keep the bike as straight as you can, and use both brakes smoothly. If you are in traffic, look, signal if you safely can, and aim for the left edge, a lay-by, a wide verge, or a safe entrance.
2. Get to a safer pause. Dismount and move yourself and the bike fully out of the way of vehicles, cyclists, and pedestrians. If you are near a junction, move past it first if that is safer than stopping there.
3. Make yourself visible. In darkness or poor visibility, turn on your front and rear lights. A flashing mode can help where appropriate. Stand where approaching drivers and riders can see you early, not hidden on a blind bend.
4. Check for immediate hazards.
   • If the chain has snapped, check for loose metal on the road or path. Only pick it up if you can do that without stepping into danger.
   • If the chain is jammed near the rear wheel, move the bike slowly; a jam can suddenly stop the wheel turning.
   • If the derailleur is bent into the spokes, stop rotating the pedals or wheel.
5. Decide whether this is a simple reset.
   • If the chain is simply off the gears and not wedged, not near the spokes, and not locking anything: keep your hands clear of the teeth, lift the rear wheel slightly, and gently turn the pedals by hand or roll the wheel to see if the chain reseats.
   • If the chain is wedged hard between the cassette and spokes, wrapped tight around the crank, caught in the derailleur, or stopping the pedals from turning: stop trying to rotate anything. Push the bike to a safer place if it can roll without dragging the jam tighter.
6. Only attempt a roadside repair if you have the right kit and feel steady enough. A temporary repair may be possible with a chain tool and the correct quick link for your chain. If you do not have those, or the derailleur or spokes look bent, do not improvise beside traffic.
7. Get to a safe end point without riding unsafely.
   • Push the bike as a pedestrian to a safer area, station, shop, or well-lit place.
   • Call someone for a lift, use a taxi that can take a bike, or use public transport where bikes are permitted.
   • If you feel at risk where you have stopped, move again to a safer place before making calls.
8. Use emergency help only for danger, not routine repair. Call 999 if there is immediate danger to life or serious risk, for example if you are stranded in a live lane and cannot get clear. If it is not an emergency but you need police help or advice once you are safe, call 101.