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  1. #1
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    I keep snapping my chain!!!

    I built my first bike recently and it rides amazing. The only problem I have is that the chain breaks almost every ride, actually twice today I have a sram pc991 chain, sram xo rear der., x9 front der., race face evolve crankset and sram pg990 cassette. I have repaired the chain many times and I hear that can weaken the chain. I've also heard that they way the drivetrain is setup can cause the chain to snap, which finally leads me to my question: How would the drivetrain be setup wrong as to cause the chain to snap? By the way the chain snaps in all different circumstances:attacking in high gear and easing up long climbs. And im not dumb enough to cross the chain up. Any other advice about what could be causing it would be appreciated.
    Thanks steve

  2. #2
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    You're probably placing the chain flawly.

  3. #3
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    Quote Originally Posted by taprsnap8888
    I have repaired the chain many times and I hear that can weaken the chain.
    If you are just pushing an existing pin back in to "repair" the chain, it will probably break at the same place. Others may disagree.

    Park Tool Chain Installation

  4. #4
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    Making and breaking a chain many times will weaken it.

    Too many repairs and a chain is toast.


    Other things that can hurt it are worn chainrings/cassette - or poor gear selection.
    There are certain gears that you should try not to (ever) use, because its not good for your chain.

  5. #5
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    try a new chain, go buy an xtr/da...who knows, maybe that chain just sucks, maybe it doesnt like you....id try a new one...plus i read a few bad reviews with the 991

  6. #6
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    2nd the advice to buy a new chain and install it, preferably an XTR/Dura Ace - they're the best Shimano has to offer and are string and cheaper than SRAM.

  7. #7
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    Second the advice on the new chain first... But would advice checking the chainrings and cassette too.


    Xtr/DA isnt a bad chain - I prefer KMC chains but both work.
    The downside to Xtr/DA chains (like all shimano) is that the pins arent reuseable, so you need spare links to remake the chain.

  8. #8
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    thanks guys definetley gonna buy a new chain after todays ride. The chainrings and cassette are 3months old so they aren't worn out.

  9. #9
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    What bike is it? If it is a duelly the chain may be too short.

    The standard measure (big cog/big ring + 2 links) on some bikes may stop the rear suspension from reaching full travel therefore causing the chain to snap when you bottom out.

    Put your chain through the derailleur as normal and either remove the shock or let the air out and check the chain with the rear fully compressed.
    cheers
    Pagey

  10. #10
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    i took a quick look at the title and text of your post...spotted the problem immediately....get rid of sram chain..only run shimano chains...that stupid sram quicklink or whatever simply breaks under torque...i know, i've broken three sram chains, all at the link, which seems to vaporize stymying efforts to find it as proof

    anyway...get any level shimano, that makes taking the chain off harder because you need the chain tool...keep a quicklink in your pack just in case...but then i've never broken a shimano chain
    "He can make even a global summit meeting seem like a kegger." M. Dowd, NY Times, 19 July 2006

  11. #11
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    Quote Originally Posted by adamantane
    i took a quick look at the title and text of your post...spotted the problem immediately....get rid of sram chain..only run shimano chains...that stupid sram quicklink or whatever simply breaks under torque...i know, i've broken three sram chains, all at the link, which seems to vaporize stymying efforts to find it as proof

    anyway...get any level shimano, that makes taking the chain off harder because you need the chain tool...keep a quicklink in your pack just in case...but then i've never broken a shimano chain

    Personally I find the problem to be with Sram chains and sram powerlinks - i think a personal thing, some people dont put enough abuse on to break them and others do

    Ive had no problems with either kmc chains or their version of the powerlink

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