If I change my cassette to a new one, should I also change the chain?

I measured the chain with a wear gauge and it's ok.

Just to emphasize the obvious: I'm changing the cassette to one of exactly the same type.

3 Answers 3


Depends on how worn the chain is. If it's relatively new go ahead and use it. If it's at or approaching 0.5% stretch, just get a new one.

  • I have a simple wear gauge, which say ok or not ok. How I can measure the 0.5% stretch?
    – Michael D
    Commented Sep 5, 2019 at 12:21
  • 1
    How long have you had the chain, any idea of how many miles? Does the wear gauge feel like it would go in if you forced it? Commented Sep 5, 2019 at 12:41
  • About 6 months, I would estimate it as about 250 miles. Yes, the wear gauge would go in if I force it.
    – Michael D
    Commented Sep 5, 2019 at 12:49
  • 2
    250 miles is not very much, especially if you are not riding hard. Commented Sep 5, 2019 at 14:00
  • 2
    At 250 miles the chain is near new unless it was (very) poor quality. I'd keep it on.
    – Carel
    Commented Sep 6, 2019 at 7:05

As a rule of thumb, new cassette and new chain. Keep the old one as a spare, but 250 miles is nothing and would be good to go with a new cassette. Generally you should get 2 to 3 chains per cassette.


The consensus seems to be that a worn chain will accelerate cassette and chainring wear. I think if it’s not worn much (you could measure with a sliding caliper) you could keep using it. Otherwise install a new chain and use the current chain when it’s time for a chain replacement.

Worn chain on new chainrings can cause chain suck, but I think this is not the case for cassettes.

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