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  1. #1
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    Chain keeps snapping off

    Looking for some help. Iíve been having some trouble with my drivetrain (Shimano 5800). The problem Iím having is that when I put a lot of force/torque through the pedals (ie: standing start sprints) my chain violently snaps off the front chainring. It happens on all the gears in the rear derailleur if the torque is high enough. Iíve messed with the limit screws and they are dialed in pretty good. Iíve tried multiple cassettes to eliminate that from being the problem. I changed the chain a couple days ago but I forget if I had the problem before I changed it. I noticed that one link on the chain seats weird/catches on the front chainring.

    Any help/suggestions would be appreciated. Thanks
    Last edited by lights10; 3 Weeks Ago at 10:52 PM.

  2. #2
    Adorable Furry Hombre
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    How worn are those chain rings? Hard to tell from a video, but they looked substantially shark finned. A close up still photo of the teeth would help

  3. #3
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    They have about 15,000 miles on them. I can try swapping cranks from my other bike to see if that makes a difference.

  4. #4
    'brifter' is a lame word.
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    Jesus, your chainrings are toast! It isn't rocket science, especially after you put a new chain on...that just makes it worse.
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  5. #5
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    Shift the rear to the smallest cog and then check each and every link for smooth movement. It may be a stiff link or a link that has a twist in it. Why did you put in a new chain? Was the old one well worn? A worn chain will eat up a chainring pretty quickly. Well maintained chains won't wear out chainrings very much at all.

    It might be a good idea to just swap in a new Chainring with a new chain at the same time.

  6. #6
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    The chain was replaced because it was time to change it. I just switched cranks from another bike on to it and that solved the problem. Thanks for the advice.

  7. #7
    'brifter' is a lame word.
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    Quote Originally Posted by lights10 View Post
    The chain was replaced because it was time to change it. I just switched cranks from another bike on to it and that solved the problem. Thanks for the advice.
    By the look of that chainring I'd say it was somewhat past the time to change it.
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  8. #8
    RoadBikeReview Member
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    Quote Originally Posted by lights10 View Post
    The chain was replaced because it was time to change it. I just switched cranks from another bike on to it and that solved the problem. Thanks for the advice.
    another thing to remember is to maintain your chain even if it's only being used indoors(esp' due to sweat). Cleaning, lubing, checking and replacing when worn will get you years and years out of a chainring.

    lubing---------> https://youtu.be/MuwS_nSevy4?t=190
    plenty of info' here about lubing and cleaning.

    checking for wear------->> https://www.youtube.com/watch?v=gXd-3UnqoaM

    good luck.

  9. #9
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    Quote Originally Posted by lights10 View Post
    They have about 15,000 miles on them. I can try swapping cranks from my other bike to see if that makes a difference.
    Your chainrings are toast - especially if you never changed the chain in those 15,000 miles. A chain and gears effectively "marry each other", so a new chain will not mesh correctly with worn gears.

    New chain + old gears = The symptoms you described.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

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  10. #10
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    Part of me wants to believe this is a 'troll' post.......
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