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  1. #1
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    Front Derailleur Clearance Issue

    So, I'm installing a Deore M590 on a friend's Raleigh Eva 4.0 (3x8), and I'm running into an issue where the bottom of the inside cage isn't clearing the middle chainring when shifting up to the largest ring.

    I've got the derailleur clamped on and aligned properly, 1-2mm of clearance for the big ring's teeth and the bottom of the outside cage, and everything is parallel.

    A couple shots to hopefully illustrate the issue:




    Any thoughts?
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  2. #2
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    After some thought & pulling the new derailleur off again, the cage looks to me to be way too tall. Taller than the previous/stock derailleur (TX-51). I was hoping to upgrade the front derailleur for her, but the M590 apparently isn't an option. Guess I'll just have to take the old to compare cage height to make sure there is enough vertical clearance from ring to ring.

    A side note: Would that M590 be for a 2x setup? I can't imagine it would work on a 3x, unless the outer ring was quite a bit smaller...
    trust the tread

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    '07 Bianchi Roger

  3. #3
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    Spec for that derailleur is 12 minimum difference in teeth between large and middle rings.
    If you raise the derailleur up to miss the middle ring, it will probably work fine.
    There is a FD-M590-10 for a 10 tooth difference.

  4. #4
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    Maybe just the camera angle but it looks bent. The front part of the cage looks a lot closer to the big ring then the back part.

  5. #5
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    Front Derailleur Clearance Issue

    Quote Originally Posted by mfisher1971 View Post
    After some thought & pulling the new derailleur off again, the cage looks to me to be way too tall. Taller than the previous/stock derailleur (TX-51). I was hoping to upgrade the front derailleur for her, but the M590 apparently isn't an option. Guess I'll just have to take the old to compare cage height to make sure there is enough vertical clearance from ring to ring.

    A side note: Would that M590 be for a 2x setup? I can't imagine it would work on a 3x, unless the outer ring was quite a bit smaller...
    Simple.
    Just raise the derailleur.
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  6. #6
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    Front Derailleur Clearance Issue

    Quote Originally Posted by J.B. Weld View Post
    Maybe just the camera angle but it looks bent. The front part of the cage looks a lot closer to the big ring then the back part.
    Normal and not unusual or a problem.
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  7. #7
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    Quote Originally Posted by shiggy View Post
    Normal and not unusual or a problem.
    To be bent? Like I said it's probably just the angle fooling me but I have seen many that got tweaked in that manner.

  8. #8
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    Front Derailleur Clearance Issue

    Quote Originally Posted by J.B. Weld View Post
    To be bent? Like I said it's probably just the angle fooling me but I have seen many that got tweaked in that manner.
    I have NEVER seen a FD bent in that direction. The pivot links would need to be damaged for that to happen, or the derailleur cage grossly twisted.
    The gap is there because of a steeper STA or the FD was designed for a larger chainring. Still functions just fine when the height is set correctly.
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  9. #9
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    It's not bent at all. The pivots and rivets are just fine, and the angles where the cage is meant to be bent are perfect. I think it's the 10 vs 12 tooth spec issue. This bike has 42-32 big-middle rings.

    Thanks for the input all...
    trust the tread

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    '07 Bianchi Roger

  10. #10
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    The M590 is spec'd for a 9 speed crank which typically came with a 44T big ring where as 8 speed typically came with a 42T big ring (like Shiggy said with a 12T difference). You can make it work with an 8 speed, but you will have to raise it up as others have said otherwise the inner cage will hit the middle ring. I have done this many times with LX M580 & M590 front derailleurs. Even though it will be a little higher, it should still shift fine.

  11. #11
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    Quote Originally Posted by shiggy View Post
    I have NEVER seen a FD bent in that direction. The pivot links would need to be damaged for that to happen, or the derailleur cage grossly twisted.
    The gap is there because of a steeper STA or the FD was designed for a larger chainring. Still functions just fine when the height is set correctly.

    I guess it's just because I've spent a lot of time working on bikes for people that have no idea how to ride them (college commuter kids) but I'm sure I've seen at least 100 bent that way, and a lot of other ways too.

    I am aware that using a derailleur designed for smaller rings will look like that too, and in that case raising it will work fine. I was just throwing it out there that it could possibly be a little tweaked because I have seen quite a few that were. It is now clear to me that this is not the case here.

    I'll go away now.

  12. #12
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    Front Derailleur Clearance Issue

    Quote Originally Posted by J.B. Weld View Post
    I guess it's just because I've spent a lot of time working on bikes for people that have no idea how to ride them (college commuter kids) but I'm sure I've seen at least 100 bent that way, and a lot of other ways too.

    I am aware that using a derailleur designed for smaller rings will look like that too, and in that case raising it will work fine. I was just throwing it out there that it could possibly be a little tweaked because I have seen quite a few that were. It is now clear to me that this is not the case here.

    I'll go away now.
    I have spent more than a few years in bike shops and can not even think of a way to bend a FD that way, especially not just from poor shifting or abusive riding.
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  13. #13
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    Quote Originally Posted by Slash5 View Post
    Spec for that derailleur is 12 minimum difference in teeth between large and middle rings.
    If you raise the derailleur up to miss the middle ring, it will probably work fine.
    There is a FD-M590-10 for a 10 tooth difference.
    this.
    I had the same issue when switched my outer 44 ring for a 40 in my 3x9 drivetrain. Then picked a Dyna sys 3x10 derailleur and problem gone. They are designed to work with smaller tooth diff since largest ring is 42 I believe, so cages have lower profiles
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