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  1. #1
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    Rough PG990 cassette?

    Hmmmmm. Here's an interesting one. My friend ordered a NIB '07 PG 990 cassette with the red bling(he was envious of mine) After installation and a test drive, he felt a noticable roughness in the smallest 3 cogs. After swapping for mine and back and forth with many combos, - sure enough, there seems to be a problem with the 3 cogs! There is a noticable difference with the design of my cogs ('05 or '06) and his.
    If anyone else has this cassette, the test is simple. With the chain in the big chainring, pedal slowly and shift from the 4th cog to the 3rd and so forth. You may feel a noticable difference in the smoothness going from the 4th to 3rd. So for now, he's running with the red bling main body and 3 shimano xt cogs....
    Anyone???

  2. #2
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    I don't see that you mentioned if he replaced the chain...if the chain is worn while the cassette is new, this can cause roughness. It may be that its smooth on your cassette because its slightly worn so it matches up with his chain.

    Of course...if he did replace the chain then this theory is DOA

  3. #3
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    I will always pay the money to replaced the chain at the same time. So yes, new chain......
    We actually tried a few different chains on 2 different hubs wiht 3 different cassettes. We really tried every combo we could.

  4. #4
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    Have you call where ever you bought it from to return it? If you don't plan on returning it, maybe consider doing a little work on those 3 cogs with a file or sandpaper. I know when I first got my XT cassette it was noisy as hell and I switched back to my LX one for a while, then yesterday I switched back and it's not noticeable to me now - might be I'm not hearing it or the chain is newer now, I dunno. Anyways I'm not complaining and like the weight I managed to drop.
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  5. #5
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    I just put a new PG990 and new chain on my wife's bike and there is no problems like you describe.
    I'm not very smart, but I can lift heavy things

  6. #6
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    arent the third and fourth cogs flat??may be you have installed them on reverse??

  7. #7
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    That's what I was thinking. My 990's are flat. The XT's that we replaced are flat. I know it is possible to put the 3rd gear on backwards but the shifting ramps are obvious. Good thought...
    .The "rumbling" is not super apparent, but noticable if you are sensitive to your drivetrain. If the bike is on the stand, you really can't feel it. When you pedal slowly around the driveway there is a noticable roughness felt through the pedals. I guess we will be calling Sram tommorrow

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