Chain wear limits: when to replace your chain

Short answer

Replace your chain when wear reaches 0.5% on 11-, 12-, and 13-speed drivetrains, 0.75% on 10-speed and below, or 1.0% on single-speed. For SRAM Eagle 12-speed chains, including Eagle T-Type (Transmission), the limit is 0.8% on a SRAM-approved checker.

A chain doesn’t really “stretch”: the metal doesn’t get longer. Instead, the pins and bushings inside each link wear, and that play adds up along the chain. 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 come from Park Tool’s chain-checker instructions and SRAM’s Eagle chain documentation (both linked below, checked October 3, 2026). Park Tool’s guidance covers 11-speed and 12-speed drivetrains directly; Drais applies the same 0.5% limit to 13-speed drivetrains as a conservative default until a manufacturer source for 13-speed is published.

Running a SRAM Flattop road chain? Flattop has a different cross-section and is not covered by SRAM’s Eagle 0.8% guidance; follow SRAM’s current Flattop documentation and use a checker from their approved-tools list — 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:

1. Put your bike in a stable position and shift the chain onto the largest chainring.
2. Insert the checker into the chain following the tool manufacturer’s instructions.
3. Does the 0.5% side drop in fully? On an 11-, 12-, or 13-speed drivetrain, your chain is due for replacement.
4. 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 kilometers are really on your chain? Register your chain as a part in Garage and Drais adds up the kilometers from your rides, so you know when it’s time to measure again.

Sources

• Park Tool blog article “When to Replace a Worn Chain”; published February 17, 2017 · Checked on October 3, 2026 · https://www.parktool.com/en-us/blog/repair-help/when-to-replace-a-chain-on-a-bicycle
• SRAM Technical Support article “When should I replace my SRAM Eagle chain?”; updated September 11, 2026 · Checked on October 3, 2026 · https://support.sram.com/hc/en-us/articles/5928711817755