chain rubs on large chain ring when in 4 smallest rear cogs
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  1. #1
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    Unhappy chain rubs on large chain ring when in 4 smallest rear cogs

    I just upgraded my 1989 peugot with a new ultegra BB, and double cranks. I have a 8speed HG cassette and am using an older shimano 600 RD.

    For some reason when the chain is in the small chain ring and in any of the smallest 4 rear cogs , the chain rubs against the large chainring. I understand this may be possible in the 2 smallest cogs, but certainly not 4.

    Can anyone help resolve this problem.

    Thank you!

  2. #2
    Diesel Engine
    Reputation: Mike Prince's Avatar
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    Been discussed many times here

    Follow this link. The search function is a useful tool....

    http://forums.roadbikereview.com/sho...ight=Chain+rub

    Hope this helps,
    Mike

  3. #3
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    Thanks Mike. I found that thread as well, after I posted. I should have looked better before hand. Thanks for responding. I'm going to give the BB placer a try.

    Thanks again.

  4. #4
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    Quote Originally Posted by mdevos
    Thanks Mike. I found that thread as well, after I posted. I should have looked better before hand. Thanks for responding. I'm going to give the BB placer a try.

    Thanks again.
    What kind of chain are you using? SRAM chains are a tad wider than Shimano chains. I haven't tried it myself yet, but when my current chain wears out I'm going to try a Shimano chain and see if that will solve the problem. Honestly, it stands to reason that matched components shouldn't do this.

  5. #5
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    chain/ring rub

    Also check to see that the inner chain ring is not reversed. On Shimano crank sets the tooth count stamping "39" on the inner ring should face to the left, the big ring should face to the right. A long shot but worth checking.

  6. #6
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    Quote Originally Posted by Spoke Wrench
    What kind of chain are you using? SRAM chains are a tad wider than Shimano chains. I haven't tried it myself yet, but when my current chain wears out I'm going to try a Shimano chain and see if that will solve the problem. Honestly, it stands to reason that matched components shouldn't do this.
    I am using a Shimano IG 30 chain. Do you know if upgrading to the HG 93 which is a narrow 9speed chain will help. Is a 9 speed chain even compatible with an 8 speed cassette?

    Thanks

  7. #7
    Old, slow, and fat.
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    Quote Originally Posted by mdevos
    I just upgraded my 1989 peugot with a new ultegra BB, and double cranks. I have a 8speed HG cassette and am using an older shimano 600 RD.

    For some reason when the chain is in the small chain ring and in any of the smallest 4 rear cogs , the chain rubs against the large chainring. I understand this may be possible in the 2 smallest cogs, but certainly not 4.

    Can anyone help resolve this problem.

    Thank you!
    The more gears you have in the back, the more the chain's going to rub on the big ring.

    Especially with a 39-tooth inner ring.

    Best advice: live with it AND DON'T RIDE THOSE GEARS.

    There's overlap between the small ring/smaller cogs and the large ring/bigger cogs. Try that instead.

    Mike
    I've moved back to NoVA. PLEASE change the weather!

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