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  1. #1
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    What else have I damaged?

    My bike was working well then something happened and it started skipping in the higher end of the cassette on a ride.
    This then skipped as I was sprinting and caused me to crash.
    I tried to set up the derailleur adjustment but couldn't get it sorted so I tried a bike shop who did no better but said I might need new cables.
    They did spot that I had bent the chain ring in the crash.
    I have since discovered the mech hanger was bent so I replaced it but it is no better. Maybe even worse. Could the frame be bent?
    The cassette has a wobble when turning, could I have bent the axle?
    Should I replace the rear mech next?
    Any ideas as I don't want to keep throwing money at it and getting nowhere.
    Thanks
    Grae

  2. #2
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    here are a few ideas. (listed in the easiest to fix to hardest)

    1. new cables always seam to help out issues
    2. new chain (the skipping could originally be from a stretched chain, also make sure you new chain is the correct length)
    3. new cassette (cassette could be worn our as well)
    4. align your new mech hanger (make sure your wheel / axis true before )
    5. check to see if your rear hub is bad (the cassette will appear to wobble when free wheeling)

  3. #3
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    i agree with 2zmtnz

    If you like the bike and want to continue investing in it(not thinking of buy a new bike soon) then i would swap out the cables, install a new front chainring, and swap on a new chain on your own. Then I would pay a bike shop to realign your dropout(mech) hanger, they should have a tool that is a long bar that threads into the hanger and basically has a staight edge that they use as a reference to realign the hanger with the bike. Then i would have them service your rear hub/casset because unless you have a name brand hub(dt swiss, hope) then finding service information/parts can be difficult. You may get lucky and not have to replace the rear derailleur but im pretty sure they were designed to hit rocks.

  4. #4
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    Thankyou
    I think I will start with the cables then.
    I used the spare rear wheel method to align the old mech hanger and it helped but still jumped at one end of the cassette.
    Thought the new hanger would solve everything but it made it worse.
    The chain seems a bit floppy side to side so I will swap that but the chain rings and cassette don't look worn.

  5. #5
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    I have noticed something else odd.
    My cassette has a flat spot.
    Not a wobble and not a single bent sprocket but looks like a small buckle across all of the sprockets.
    Is this normal? Something for shifting? Or have I done some weird damage?

  6. #6
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    Quote Originally Posted by 2zmtnz View Post
    5. check to see if your rear hub is bad (the cassette will appear to wobble when free wheeling)
    What? You need to explain what you mean by a "bad hub" and how this could be the result.
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  7. #7
    since 4/10/2009
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    Quote Originally Posted by tequilagrae View Post
    I tried to set up the derailleur adjustment but couldn't get it sorted so I tried a bike shop who did no better but said I might need new cables
    It sounds like there's a lot of stuff buggered. If you don't know how to fix it yourself, and it sounds like you don't even know what to look for, then the bike shop is your best resource. But they're going to have to spend time with it, and you're going to have to let them replace broken/worn stuff (which means, you're going to be spending money).

    If the shop you took it to just looked at it for a few seconds, and shrugged, then you should probably take it to a different shop.

  8. #8
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    Quote Originally Posted by tequilagrae View Post
    I have noticed something else odd.
    My cassette has a flat spot.
    Not a wobble and not a single bent sprocket but looks like a small buckle across all of the sprockets.
    Is this normal? Something for shifting? Or have I done some weird damage?
    https://www.google.com/search?q=SHIM...E8RDJFkWaeAgM:

    This what cassettes look like. I am assuming you have a shimano cassette, they have shaped teeth that help the shifting. If your cassette rings are not straight perpendicular to the axle, then there is something wrong with the cassette but it would be near impossible to damage all the cogs on a particular cassette at the same time.

    I suspect you may have tweaked your hanger and/or derailleur, which when standing and cranking either sent it into the spokes or caused the chain to slip. I would check to ensure that rear derailleur is straight (gears on derailleur parallel with cassette gears) since you already replaced the hanger. I would then ensure that your chain doesn't have a bent link or multiple bent links in it. Work it backwards through the rear derailleur and see if anything makes the tensioner wheels and jockey move. If they move outside of the normal motion then it is probably a bent link and it is grabbing on the gears or jockey as it goes through.

    Cassettes, actually the freehub, will have a little wobble under rotation, mostly normal. If the hub was bent you could tell because A. your wheel would look like it wasn't straight in your frame and B. your disk calipers or caliper brakes would rub the rotor or rim respectively (though maybe less chances with caliper brakes).

    I think new cables would assist in better shifting but probably isn't the source of issues, though may have instigated it all by being enough out of adjustment to make the cassette miss-shift.

    Care should be taken in replacing chains. Chains stretch as they age (well they wear actually but it seems like they get longer) and the space between the rollers gets incrementally larger and the cassette and the chainrings can wear with this so when you replace a chain, which is nice and easy, the new chain will skip. It might not skip in all gears either, just the ones you use the most. Cassettes seem to wear quicker as the gears are smaller, than chainrings but both can contribute to this. Depending on how old your chain is you might need a cassette or even chainrings. With regular riding I might get 1 year out of chain, commuting I replace mine every 9-10 months, or after the rainy season. There are instructions to determine if your chain has stretched too much, as well as tools available. Check before going with a new chain, as if the wear is too great, it will make your chain and drivetrain even less reliable.
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  9. #9
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    take it to a bike shop that does not suck. a good bike shop would have a mechanic who would check the frame with a frame alignment gauge, and the derailleur hanger with a hanger tool, along with all the other diagnostics that any good mechanic would think to do.

    new hangers should be checked for alignment too. some of the less precise ones need to have a DAG put on it and tweaked. there's no way to manufacture a hanger that's perfect, so a little tweak is usually part of the install.

  10. #10
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    Took it to bike shop.
    Mech was bent along with the hanger.
    Haven't been out on it probably yet but it seems OK.
    Thanks everyone for the advice.

  11. #11
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    thanks for the followup. I just saw this thread and was going to say there is almost no way it is the cables.

    Bent hanger/derailleur is almost guaranteed to be the issue.

    Get a friend to shift up and down and you can watch it from the back and see why it is shifting rough. You will typically be able to get it to shift properly for part of the cassette, but not the whole thing.

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