I replaced a worn chain the day after the chain indicator check showed 100% wear. I replaced the 8 speed 52 full link chain with 52 + a half link plus a quick connector. The quick connector is fully seated.

Chain skip is happening on all gears under load. The bike is a loaded work bike and did not have skip on the old chain. The old chain was last checked at 2200 or 2400 km.

Why am I experiencing chain skip?

  • 3
    The chain and cassette tend to wear together and ideally should be replaced together. I doubt the issue is with the quick connector.
    – KeithWM
    Sep 29 '16 at 12:02
  • How much distance did the old chain have on it? The cassette will probably have worn to match the chain's wear. Sep 29 '16 at 13:02
  • The old cassette and chain were identically aged. My previous experience has been that a cassette has four or so chains in it. Sep 29 '16 at 13:08
  • 2
    you don't mean 100% wear do you? That would imply the chain was double the length it started as. My gauge goes 0% to 1% and I usually replace at 0.5%. if it went to 1% I'd probably replace the cassette also
    – Vorsprung
    Sep 29 '16 at 13:53
  • Do you get chain skip in all gears or is there one gear you ride in a lot more?
    – Criggie
    Sep 29 '16 at 18:55

I suggest you change your cassette now, before you get accelerated wear on your chain. At 1% chain stretch, the cassette was as worn as the chain.

Have a very close look at the cassette with your chain in the gear that skips the most. I suspect that if you add tension by pressing lightly on the pedal by hand, that only one link is making good contact with cassette teeth, and there may even be light visible "under" the chain.

Of course this is based on rule of thumb.

  • 1
    I was under the impression 1% wear was at the boundary of being in spec for 8 speed, 0.75% for 9/10 speed and 0.5% for 11 speed. The OP has an 8spd. That said, the gauges typically don't measure past 1% so it may actually be more.
    – Rider_X
    Sep 29 '16 at 19:47
  • @Rider_X true - those gauges aren't particularly accurate. I've had one reading 0.75% worn that was brand new. Better to log one's mileage with a tool and replace based on distance covered.
    – Criggie
    Sep 29 '16 at 20:50
  • 1
    I have never had a new chain read anywhere beyond 0.25%, usually always less. I also measured the reader against Vernier calipers and got a consistent reading between marked percentages. Not sure what is going on for you, did you bend your tool?
    – Rider_X
    Sep 29 '16 at 21:00

It turns out the core issue was frame deformation from a 2 km / h collision with a car near the bottom bracket bending the rear triangle out of true and this changing the chain line. Unexpected.

  • Good sleuthing! Thank you for the followup and closure.
    – Criggie
    Nov 1 '16 at 6:15

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