Troubleshooting › Shifting & chain

Chain skips or jumps when pedaling hard: causes and fixes

Skipping under load usually means worn parts, especially if it happens in the gears you use most.

Check it on your own bike

1. Worn chain · Most likely

   Measure with a chain checker. A stretched chain no longer meshes with the cogs.

   Fix: Measure chain wear · Replace chain (with sizing)

2. Worn cassette or freewheel · Most likely

   Skips on a brand-new chain mean the cogs are worn too (shark-fin teeth).

   Fix: Remove and install cassette · Remove and install a MicroSpline cassette · Remove and install a freewheel

3. Shifting out of adjustment · Most likely

   If it skips or hesitates between two gears, adjust the cable tension with the barrel adjuster.

   Fix: Adjust rear derailleur (limits + indexing)

4. Bent derailleur hanger · Sometimes

   Look from behind: the derailleur pulleys should hang straight under the cogs. Bent after a fall? Straighten the hanger.

   Fix: Check and straighten derailleur hanger

5. Stiff chain link · Sometimes

   Backpedal slowly and watch the derailleur: a stiff link makes the cage jump once per chain turn.

   Fix: Replace chain (with sizing) · Clean and lube chain

6. Worn chainring or loose single-speed chain · Sometimes

   Hooked chainring teeth, or a single-speed chain with more than about 1/2" of slack.

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