New chain skips on _new_ cassette

Discussion in 'Cycling Equipment' started by Karl Nelson, Apr 26, 2004.

  1. Karl Nelson

    Karl Nelson Guest

    I replaced my cassette and chain at the same time. The chain
    was an old style with bushings and it skipped on the smaller
    sprockets, which I attributed to it being pushed sideways by
    the ramps because it was too wide. However, after about
    three miles I realized that it was also skipping on the
    front chainring, which turned out to be very worn.

    Now with new chainrings and a narrower chain ("SRAM-PC58"),
    I get skipping on the 13t sprocket. (Both the 15t and 11t
    seem OK but I have ridden much yet.) Of the three miles
    ridden with the wider chain and worn chainrings, less than
    1/2 mile was probably on the 13t sprocket. Most was probably
    on the 18t sprocket.

    The narrower chain was ridden about 100 feet on the worn
    chainrings. I do see wear from this, I think: 24 links
    measure about 24 1/32 inches.

    I don't have the other chain in front of me to measure it.

    Is it possible that the chainrings wore the chain which in
    turn wore the cassette sprocket to the point where a new
    chain now skips on it, all in 1/2 mile? Any other
    explanations? Anything I can do about it?

    Also, does my thought for why the chain with bushings was
    skipping seem right? It's called a 6/7-speed chain ("KMC-
    HP20"), on a 7-speed HG cassette--it seems like it should
    have worked.

    Thanks, Karl Nelson.
     
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  2. Ron Hardin

    Ron Hardin Guest

    I've had new chains skip on new freewheels (none of this
    high tech stuff) and it stopped when the chain wore a
    little. That was years ago though.

    I'd be surprised if anything skipped on the chainring. The
    chain tends to pop off when it skips there. It's winding on
    under tension on the chainrings and so doesn't ride up on a
    tooth the way it does on a worn cog. So skipping on the
    chainring is most likely an optical illusion.

    Stiff link is the usual explanation. The stiffness only have
    to be stiff against the derailleur tension, not your
    pedalling tension.

    A skip is caused by a hook in a worn cog, which lets the
    chain pull up inside the hook, so the oncoming link doesn't
    clear the tip of the next tooth (unless the chain isn't
    stretched); the chain then rides on top of the teeth until
    the whole army gets to the top of the cog, and then
    everything slips until a random link catches a bottom tooth.
    A burr on a cog could conceivably cause the same sort of
    thing, I guess.
    --
    Ron Hardin [email protected]

    On the internet, nobody knows you're a jerk.
     
  3. Ron Hardin

    Ron Hardin Guest

    Ron Hardin wrote:
    > next tooth (unless the chain isn't stretched); the chain
    > then rides

    unless the chain is stretched

    edit error
    --
    Ron Hardin [email protected]

    On the internet, nobody knows you're a jerk.
     
  4. Nomisa

    Nomisa Guest

    [email protected] (Karl Nelson) wrote in message news:<[email protected]>...
    > I replaced my cassette and chain at the same time. The
    > chain was an old style with bushings and it skipped on the
    > smaller sprockets, which I attributed to it being pushed
    > sideways by the ramps because it was too wide. However,
    > after about three miles I realized that it was also
    > skipping on the front chainring, which turned out to be
    > very worn.
    >
    > Now with new chainrings and a narrower chain ("SRAM-
    > PC58"), I get skipping on the 13t sprocket. (Both the 15t
    > and 11t seem OK but I have ridden much yet.) Of the three
    > miles ridden with the wider chain and worn chainrings,
    > less than 1/2 mile was probably on the 13t sprocket. Most
    > was probably on the 18t sprocket.
    >
    > The narrower chain was ridden about 100 feet on the worn
    > chainrings. I do see wear from this, I think: 24 links
    > measure about 24 1/32 inches.
    >
    > I don't have the other chain in front of me to measure it.
    >
    > Is it possible that the chainrings wore the chain which in
    > turn wore the cassette sprocket to the point where a new
    > chain now skips on it, all in 1/2 mile? Any other
    > explanations? Anything I can do about it?
    >
    > Also, does my thought for why the chain with bushings was
    > skipping seem right? It's called a 6/7-speed chain ("KMC-
    > HP20"), on a 7-speed HG cassette--it seems like it should
    > have worked.
    >
    > Thanks, Karl Nelson.

    I had same problem with new chain skipping on new cassette.
    Stiff link was the culprit.

    Backpedal with the bike in a stand and you can often see the
    problem link as it comes off the cogs or pulleys. In my
    case, it was the one I drove the replacement pin through. I
    suspect this is pretty common
    - the pin presses the plates together too tightly. Just take
    a flat-head screwdriver, stick it btw plates, and gently
    flex them so they're looser. I had no problems afterwards.
    Hope this works for you.

    Nom
     
  5. Neacalban1

    Neacalban1 Guest

    also, if using a superlink of some sort, they may need
    special orientation when installed. I got a connex (I think)
    which is asymmetrical, and only goes 1 way. I didnt
    understand from the directions initially, and installed it
    correctly by accident. the next time I cleaned the chain and
    re-installed the link, it began to skip, but only in the
    11T. A Park gauge showed less than .25 wear, and I knew the
    chain had less than 1000 miles. turned out the link was on
    backwards.
     
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