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  1. #1
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    Shredded 11 tooth cog, broken teeth on both 15 and 17 tooth cogs

    Initially I was experiencing skipping under load, I thought the derailleur hanger might have bent so I had it "fixed"/realigned. The issue continued. As a result, I replaced the cassette and the chain. Within minutes of testing it out, I went to shift the front derailleur and the chain pulled up, got stuck between the crank ring and the bottom bracket leaving the $70 chain destroyed. Next up, I replaced the chain rings. Since then I haven't had any issues with the front derailleur but within a few miles of riding on the a new chain and the other new drivetrain components I was riding up a mild hill and I completely shredded the 11 tooth cog; the shop told me they would attempt to warranty the cassette but until then they just threw on my 11 tooth cog from the previous cassette. I proceeded to break a tooth off the 15 tooth cog and I started to experience more skipping under load, this occurs up to the 5th cog and in 2nd and 3rd chain rings. I also replaced my worn aluminum freehub with a steel one. Immediately following I broke a tooth off the 17 tooth cog and the skipping persists...

    By now, it has become obvious I am in desperate need of advice!

    P.S. The components are as follows:

    Noir Carbon Cranks
    XT Front
    X9 rear
    XO 3x9 shifters
    sram pg 980 9 speed cassette 11-34 (the new cassette)
    truvativ chain rings

  2. #2
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    Just to be clear that the cassette is legitimately damaged:

    Shredded 11 tooth cog, broken teeth on both 15 and 17 tooth cogs-photo-7-.jpgShredded 11 tooth cog, broken teeth on both 15 and 17 tooth cogs-photo-6-.jpg
    Shredded 11 tooth cog, broken teeth on both 15 and 17 tooth cogs-photo-9-.jpgShredded 11 tooth cog, broken teeth on both 15 and 17 tooth cogs-photo-8-.jpg

  3. #3
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    Shifting up hill under load is a bad idea. This is what happens when you do.

    The skipping sounds like cable tension to me. Maybe a combination of that and RD limit screw adjustment?

  4. #4
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    I am positive I was not shifting when I shredded the 11 tooth cog; highly unlikely on the other two occasions as well. I'm a decent sized dude though 6'2" 220lbs but I don't really think that should matter?

    I'll definitely heed the advice though. I'll have the shop take a look at the cable tension and RD adj. Thanks for feedback.

  5. #5
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    I think you got a defective cog set. It looks like the chrome plating has flaked off in places. After metal is chrome plated it needs to be cooked to drive out they hydrogen or else you get hydrogen embrittlement. They may have skipped this step. I find 11 tooth cogs to be worthless they wear out too quickly. I recommend a larger cog set a 12 as the smallest cog and add 4 teeth to the front large chainring.
    "Dish is illogical." Spoke of Vulcan.

  6. #6
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    Defective cassettes are rare, but certainly not unheard of.

    I would be looking to get a new cassette and chain out of the shop, and with those get the cables and outers done at the same time. Then with new parts on you should have some closure with the shifting.

    But it is also fair to note that some people just 'break things'. You need to be aware that you might just be one of these. Stick away form both the very cheap and very expensive.
    Rimmer - "There's an old human saying - if you talk garbage, expect pain"

  7. #7
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    The LBS threw on a Shimano cassette today, they're going to warranty the SRAM. I then put it through the absolute meat grinder and it rode like a champ. Of course only time will tell but I think I'm going to accept the defective cassette story for now. To be cautious, I'll have the cable work done as too. Thanks again for all of the useful comments.

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