Worn Bicycle Chain and Cassette

Question of the week: “This past May I bought a hybrid bike. Now, at 2300 miles, I already need a new cassette. The bike shop said it’s all the miles I put in. How many miles can a cassette take?”

A cassette can take a lot of miles. But how many depends on how much care you give your chain. There’s this myth that when you replace your chain, you should also replace your cassette. That’s only true if you’ve really worn your chain out. The pins that connect the chain links wear over time, causing your chain to get longer. After a while, the shifting gets sloppy and inefficient and the chain starts to deform the cassette cogs and the chainrings.

The trick is to replace the chain before it gets too worn. You can purchase an inexpensive chain gauge which lets you check the wear of the chain. By replacing the chain before it reaches the “replace” point, you can continue to use the same cassette. Everything is expensive these days, but replacing just the chain is a lot less expensive than replacing the chain and the cassette.

Chain Wear Gauge

Chain Wear Gauge

Chain Wear Gauge on Chain

Checking for chain wear

So, the name of the game is to keep that chain going for as long as you can. That means cleaning it and lubricating it properly. The rider who sent in this question admitted to riding in the rain a lot and not paying much attention to her chain. Both the worn bicycle chain and the worn cassette died an early death. I’ve ridden the same cassette over 10,000 miles by caring for the chain and replacing it twice.

Note: The chain gauge shown here is no longer made. But check out Park Tool’s CC-3.2 Chain Wear Indicator. It’s inexpensive and works well.

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3 comments on “Worn Bicycle Chain and Cassette
  1. Rod Bruckdorfer says:

    On my road bike, the chain will last about 4,000 to 5,000 miles with proper care. Park Tool has two chain gauge tools. The go-no-go gauge (#CC-3.2) costs about $10 and the analog gauge (#CC-2) costs about $22. I prefer the analog gauge. I use a dry lubricant and routinely wipe the chain clean after several rides and oil the chain when it starts to make noise. Even good chains are inexpensive compared to replacing a cassette or the chainrings on a crankset.

  2. Stephen Barner says:

    It’s easy to confuse precision with accuracy in chain wear measurement tools. Since almost all current tools do not measure chain wear accurately, it doesn’t make a lot of sense to pay extra for a tool that appears to be more precise. The vast majority of chain wear indicators do not measure wear in the same way the chain is loaded, and include bushing slack in the total measurement when, if fact, this has nothing to do with wear on the sprockets and cogs. You can get a much more accurate measurement of actual chain wear with a regular ruler than with these tools. On the other hand, the only risk with commercial measurement tools is that you might replace your chain before it’s really necessary and that’s not typically a bad thing. An understandable description of chain wear and accurate measurement is available at http://pardo.net/bike/pic/fail-004/000.html. A simple go-no go gauge is fine for indicating whether it’s time to make a more accurate measure with a ruler, which is best done after removing the chain from the bike.

  3. Chuck Davis says:

    That SpeedTech tool is somewhat of a classic!
    ……………still in use at my shoppe

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