Re: Chainwheels are worn out when ?

Discussion in 'Cycling Equipment' started by [email protected], Oct 21, 2004.

  1. someone to shy to reveal his name writes:

    > So, when are chainwheels actually "worn out" ?


    When the chain no longer is driven by them. With more than one
    chainwheel, this is no problem unless racing. Just use the other one
    to return home when the other actually fails.

    > I'm familiar with the symptoms of worn clusters - skipping, poor
    > shifting, etc - do shark teeth chainwheels do the same thing ?


    No, but you can get chain suck if the previous chain was badly
    elongated and the chainwheel is smaller than ~39t.

    Jobst Brandt
    [email protected]
     
    Tags:


  2. On Fri, 22 Oct 2004 02:06:37 +0000, jobst.brandt wrote:

    >> I'm familiar with the symptoms of worn clusters - skipping, poor
    >> shifting, etc - do shark teeth chainwheels do the same thing ?

    >
    > No, but you can get chain suck if the previous chain was badly elongated
    > and the chainwheel is smaller than ~39t.


    Actually, I have experienced skipping on a chainring. It was a small one,
    either 30 or 32 teeth, but the skipping was essentially the same as with a
    rear sprocket. It was badly shark-toothed. Also, when the teeth are so
    shark-shaped that they bend over or develop burrs, you will have shifting
    problems.

    --

    David L. Johnson

    __o | If all economists were laid end to end, they would not reach a
    _`\(,_ | conclusion. -- George Bernard Shaw
    (_)/ (_) |
     
  3. On Fri, 22 Oct 2004 00:47:19 -0400, "David L. Johnson"
    <[email protected]> wrote:

    >On Fri, 22 Oct 2004 02:06:37 +0000, jobst.brandt wrote:
    >
    >>> I'm familiar with the symptoms of worn clusters - skipping, poor
    >>> shifting, etc - do shark teeth chainwheels do the same thing ?

    >>
    >> No, but you can get chain suck if the previous chain was badly elongated
    >> and the chainwheel is smaller than ~39t.

    >
    >Actually, I have experienced skipping on a chainring. It was a small one,
    >either 30 or 32 teeth, but the skipping was essentially the same as with a
    >rear sprocket. It was badly shark-toothed. Also, when the teeth are so
    >shark-shaped that they bend over or develop burrs, you will have shifting
    >problems.


    Dear David,

    Twice, I've replaced badly worn chains, installed new rear
    gear clusters, and had the new chains skip badly on a worn
    53-tooth chain-ring.

    The first time, the new chain just skipped when I pedalled
    hard on the flats in high gear. New front chain ring, no
    more skipping.

    The second time, several years later, I put on the new rear
    cluster and the new chain and figured that I'd just take it
    easy if the front was too worn and started skipping. The new
    chain came off the front 53-tooth on the first downstroke as
    I set off.

    Startled, I flipped the bike upside down, pulled the chain
    back onto the sprocket, ran front and rear derailleurs up
    and down while cranking the pedals with one hand, and saw no
    obvious problem. I set the chain back onto the 53-tooth
    front and one of the middle gears on the back, set the bike
    right side up, started off again, and--presto!--chain off
    the front sprocket. I replaced the worn 53-tooth, everything
    began to work normally.

    At a rough guess, both chain rings had over 20,000 miles on
    them. They may have worn more than usual or in an odd
    pattern due to shamefully worn chains.

    Carl Fogel
     
  4. > At a rough guess, both chain rings had over 20,000 miles on
    > them. They may have worn more than usual or in an odd
    > pattern due to shamefully worn chains.
    >
    > Carl Fogel


    Carl: I get about 15,000 miles out of Ultegra (and possibly a bit more from
    DuraAce) chainrings before I notice a significant decline in shifting
    performance and change them. Rear cassettes go for about 10,000 miles, but
    chains, for my weight and the hills I ride, get only about 1800-2000 miles
    before they're toast. By toast I mean significantly reduced shifting
    performance. By the classic wear standards, I'm replacing them just before
    Jobst would say I need to. That's OK; if spending a few more dollars on
    chains means things shift better, I'll spend the $$$.

    For what it's worth, I've never worn a chainring to the point that the chain
    skipped over it, but I've seen quite a few customers whose bikes have done
    that. It's tougher to diagnose than a skipping rear cassette; you really
    don't believe it's happening at the front. Sometimes I'll even have someone
    ride it in the parking lot while I watch what's happening.

    --Mike-- Chain Reaction Bicycles
    www.ChainReactionBicycles.com


    <[email protected]> wrote in message
    news:[email protected]
    > On Fri, 22 Oct 2004 00:47:19 -0400, "David L. Johnson"
    > <[email protected]> wrote:
    >
    >>On Fri, 22 Oct 2004 02:06:37 +0000, jobst.brandt wrote:
    >>
    >>>> I'm familiar with the symptoms of worn clusters - skipping, poor
    >>>> shifting, etc - do shark teeth chainwheels do the same thing ?
    >>>
    >>> No, but you can get chain suck if the previous chain was badly elongated
    >>> and the chainwheel is smaller than ~39t.

    >>
    >>Actually, I have experienced skipping on a chainring. It was a small one,
    >>either 30 or 32 teeth, but the skipping was essentially the same as with a
    >>rear sprocket. It was badly shark-toothed. Also, when the teeth are so
    >>shark-shaped that they bend over or develop burrs, you will have shifting
    >>problems.

    >
    > Dear David,
    >
    > Twice, I've replaced badly worn chains, installed new rear
    > gear clusters, and had the new chains skip badly on a worn
    > 53-tooth chain-ring.
    >
    > The first time, the new chain just skipped when I pedalled
    > hard on the flats in high gear. New front chain ring, no
    > more skipping.
    >
    > The second time, several years later, I put on the new rear
    > cluster and the new chain and figured that I'd just take it
    > easy if the front was too worn and started skipping. The new
    > chain came off the front 53-tooth on the first downstroke as
    > I set off.
    >
    > Startled, I flipped the bike upside down, pulled the chain
    > back onto the sprocket, ran front and rear derailleurs up
    > and down while cranking the pedals with one hand, and saw no
    > obvious problem. I set the chain back onto the 53-tooth
    > front and one of the middle gears on the back, set the bike
    > right side up, started off again, and--presto!--chain off
    > the front sprocket. I replaced the worn 53-tooth, everything
    > began to work normally.
    >
    > At a rough guess, both chain rings had over 20,000 miles on
    > them. They may have worn more than usual or in an odd
    > pattern due to shamefully worn chains.
    >
    > Carl Fogel
     
  5. On Fri, 22 Oct 2004 06:28:33 GMT, "Mike Jacoubowsky"
    <[email protected]> wrote:

    [snip]

    >For what it's worth, I've never worn a chainring to the point that the chain
    >skipped over it, but I've seen quite a few customers whose bikes have done
    >that. It's tougher to diagnose than a skipping rear cassette; you really
    >don't believe it's happening at the front. Sometimes I'll even have someone
    >ride it in the parking lot while I watch what's happening.
    >
    >--Mike-- Chain Reaction Bicycles
    >www.ChainReactionBicycles.com


    Dear Mike,

    Diagnosis is extremely simple if you're extremely
    simple-minded.

    Something skips under heavy pedalling in high gear.

    Okay, time to replace the rear cluster. I wear out high gear
    cogs now and then. (But far less often after I switched from
    Sachs Aris 12-tooth cogs to Shimano 11-tooth cogs--Shimano
    must be better metal.)

    Sometimes, something still skips.

    Okay, replace the chain. I wear out chains, too.

    Damn! No question now what's skipping! As Ron put it
    elsewhere in this thread, the chain "pops off" the front
    sprocket. Replace the front sprocket.

    There, that fixed it!

    One day, I fear, something will still skip. When it does, I
    plan to look at the frame to see if it's cracked.

    Carl Fogel
     
  6. fixit

    fixit New Member

    Joined:
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    a very helpful tool is the HG/IG check from rohloff.

    http://www.rohloff.de/index.php?p=PRODUKTE/HG-IG-CHECK
     
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