Reference
Chain wear limits: when to replace your chain
When should you replace your bike chain? Wear limits by drivetrain from Park Tool and SRAM, and how to measure with a chain wear checker.
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A chain doesn’t “stretch” because the metal elongates — it wears at the pins and bushings inside each link. That increases the pitch — the distance between pins — so the chain no longer meshes precisely with the teeth of your cassette and chainrings. A worn chain then grinds those teeth down at a rapid rate.
That makes this the cheapest maintenance rule in cycling: replacing a chain on time costs a fraction of what a cassette costs. Park Tool explicitly warns that riding a chain beyond its wear limit prematurely wears out your cogs and chainrings.
The wear limits by drivetrain #
Replace your chain as soon as measured elongation reaches the limit for your drivetrain. The limits below are the guideline values published by Park Tool, supplemented with SRAM’s own specification for Eagle chains:
| Drivetrain | Replace at |
|---|---|
| Single-speed / internally geared hub | 1.0% |
| Up to 10-speed | 0.75% |
| 11- and 12-speed | 0.5% |
| SRAM Eagle 12-speed | 0.8% on a SRAM-approved checker |
Running another SRAM 12-speed chain (Flattop, T-Type)? Follow SRAM’s current documentation and use a checker from their approved-tools list — these chains have different roller dimensions, so not every standard checker gives a usable reading.
For e-bikes, use the limit for your speed count, but measure more often: a mid-drive motor puts high torque through the chain, so it wears faster.
Measuring with a chain checker #
A chain wear indicator (for example one with a 0.5% and a 0.75% side) makes the measurement a matter of seconds:
- Put your bike in a stable position and shift the chain onto the largest chainring.
- Insert the checker into the chain following the tool manufacturer’s instructions.
- Does the 0.5% side drop in fully? On an 11- or 12-speed drivetrain, your chain is due for replacement.
- Does the 0.75% side drop in fully as well? Replace on drivetrains up to 10-speed too — and inspect your cassette for wear right away.
Measure at a few different spots along the chain: wear is rarely perfectly even.
How often should you check? #
Check monthly if you ride regularly, and more often after wet, muddy, or sandy rides — grit between the links accelerates wear dramatically. How long a chain lasts varies enormously with riding style, surface, maintenance, and lubrication; measure instead of relying on mileage.
Already past the limit? #
If a brand-new chain skips over the cassette under load, the cassette has already reshaped itself to the elongated pitch of the old chain. Replace chain and cassette together, and check your most-used chainring for shark-fin shaped teeth.
Want to know how many kilometres are really on your chain? Register your chain as a part in the Drais Garage and the counter tracks your rides automatically.