Originally Posted by
Dave Mayer
I get 3,000 miles out of a chain - max. These are derailleur-based chains. I know that bushing-based single-speed chains last longer. Regardless, there is no possible way to get 12,000 miles out of a chain. Actually we have folks walk into our local bike co-op every day who get huge miles out of chains, but upon measuring the chain, it is absurdly stretched and is jumping all up and over the cassette and chainrings. The chainrings and cassette cogs have been rendered shark-finned and useless. So a $300 drivetrain repair bill - yearly.
So here is another forum discussing chain life, some don't get many miles but others do, one is a Cat 1 racer that gets 10,000 miles out of his chains:
https://www.bikeradar.com/forums/vie...php?t=12758416
Due to this discussion I went and checked my chain wear on my main bike instead of waiting for spring, and it will need a new chain, but that chain has exactly 11, 589 miles on it according to the bike computer. I checked the gears and they're fine. Even
IF I had waited too long to replace the chain and the gears went bad I still got a lot more miles out of both then what you said you get, but in this case I didn't wait too long because the gears are still good.