Originally Posted by
Leebo
Replace when worn.
Originally Posted by
10 Wheels
Clean dry and measure 12 inches for wear.
When 12 links exceed 12-1/16" it's time to replace the chain. TBH, I've got a Park checker I can drop down a few places around the chain -- I usually wait until the first one drops to squat down on the ground to measure with a ruler or tape.
Some people would rather wear cassette and chain out. Every time I've let one go past the 12-1/8" point, I end up replacing one or more front cogs as well as cassette. It's cheaper and easier to put on a new chain, usually about every 2,000 miles IME.