Troubleshooting › Shifting & chain

Chain falls off: causes and fixes

Note where it falls: off the cassette (rear) or off the chainring (front).

Check it on your own bike

1. Limit screws set too loose · Most likely

   Falls off past the biggest or smallest cog: tighten the matching limit screw a quarter turn.

   Fix: Adjust rear derailleur (limits + indexing) · Adjust front derailleur

2. Bent derailleur hanger · Sometimes

   A bent hanger pushes the derailleur into the spokes or off the cogs.

   Fix: Check and straighten derailleur hanger

3. Chain too long, or chain slap on bumps · Sometimes

   In the smallest cog the derailleur cage should still hold the chain taut.

   Fix: Replace chain (with sizing)

4. Worn narrow-wide ring or loose single-speed chain · Sometimes

   Check ring teeth for wear, or set single-speed chain tension.

   Fix: Change chainring size · Set single-speed chain tension