Repair guides › Drivetrain
Replace chain (with sizing)
Transfers your pedaling to the rear wheel. It wears out first and takes the cassette and chainring with it if you wait too long. Pins and rollers wear, so the chain gets longer ("stretch"). A worn chain skips and grinds the cog teeth into hooks. Width depends on speed count: buy the one that matches your cassette. Replace at 0.75% wear for 8/9/10-speed, 0.5% for 11-speed and up.
Open this job in RideLoadout▶ Watch it done
Tools
- Shop rags + nitrile gloves: shop towels and nitrile gloves ($)
- Chain tool: Oumers bike chain repair tool set ($)
- Quick-link pliers: Basic master link pliers ($)
- Quick links (match chain speed): Wippermann Connex Link 808 ($)
Compare Good, Better and Best for each tool
Steps
- Buy a chain that matches your speed count (count the cogs) and a matching quick link.
- Remove the old chain with link pliers at the quick link, or press a pin out with the chain tool.
- Size the new chain the same length as the old one by laying them side by side (the old one is stretched, so count links, not length).
- No old chain? Wrap the new chain around the biggest chainring and biggest cog without going through the derailleur. Biggest cog 36T or smaller: add 2 links (one inch). Biggest cog 42T or larger: add 4 links (two inches). Full-suspension bike: size it with the shock fully compressed (air out or shock off). Follow the derailleur maker's chart if it gives one.
- Route through the derailleur pulleys and cage tabs. Join with the quick link (arrow facing direction of travel if marked).
- Pull the link closed by standing on a pedal with the rear brake held.
- Shift through every gear. The derailleur cage should never be stretched straight forward in the biggest cog.
Diagram
Side view, chain side toward youChain
Signs it needs doing
- Chain skips under hard pedaling
- Noisy, gritty drivetrain
- Stiff link that clicks once per crank turn
- Rust