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  1. #1
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    Help, broken front derailleur tab

    I was adjusting the deraileur on my mom's 2003 Giant OCR 2 and somehow broke off that tab that attaches the front derailleur to the seat tube. It's a piece of aluminum which is bolted onto the frame and also bolted onto the derailleur. It has a slot in it for the derailleur to move up and down. I have no idea what this is called or where to find a new one. Are they particular to the bicycle or is it a generic part? Tomorrow I will try phoning some bike shops.

  2. #2
    Constant tinkerer FastJake's Avatar
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    I believe that's called the braze-on tab. Since it's bolted on, there's a good chance you'll be able to find a replacement and just bolt it on. When you start snapping the actual FD braze-ons off the frame you run into real trouble.

    Post a picture of it, maybe someone on here can identify it.
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

  3. #3
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    +1 "braze-on" is a name that carries forward from the days when these were brazed on to steel frames. Nowadays it's used for all attached front derailleur mounts, brazed of bolted on. If the screws aren't damaged or stripped you should be able to scrape up a new one.

    BTW- when's the last time anyone dialed a phone.
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  4. #4
    coprolite fietsbob's Avatar
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    if the front derailleur tab is pop-riveted on, the pop rivets
    can be drilled out and re done,
    if not, you have a single chainring bike from now on..

    shut off the computer and go down to the dealer that
    sold you the bike.
    Last edited by fietsbob; 05-25-11 at 11:09 PM.

  5. #5
    Senior Member jeepr's Avatar
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    Quote Originally Posted by fietsbob View Post
    aluminum frames that don't have replaceable
    dropout dérailleur tabs are scrap metal.
    Working on converting one to a replaceable rear hanger now. We will see.

  6. #6
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    Quote Originally Posted by fietsbob View Post
    if the front derailleur tab is pop-riveted on, the pop rivets
    can be drilled out and re done,
    if not, you have a single chainring bike from now on..

    shut off the computer and go down to the dealer that
    sold you the bike.
    The tab was attached to the bike with two flathead hex screws. I removed the screws and the broken half of the tab so now there are just the braze-on threaded holes in the frame. There were no rivets.

    Also, on a somewhat unrelated note, when I was adjusting the rear derailleur (9 speed Tiagra), I could either get every up-shift to work consistently or get every downshift to work, but I could not get both at the same time. Is this more likely due to gunked housing or gunked shifters or something else? Should I fiddle with the B-tensioner?
    Last edited by Dan The Man; 05-25-11 at 11:20 PM.

  7. #7
    bike whisperer Kimmo's Avatar
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    I'd call that 'tab' a front derailleur hanger.

    As for your shifting, b-screw adjustment might help, but it's most likely caused by excessive cable friction; clean and re-lube.

  8. #8
    coprolite fietsbob's Avatar
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    Dealer have the replacement part?
    did you ask a Giant brand bike dealer??
    that's not a question to get that answer here.
    Last edited by fietsbob; 05-26-11 at 12:08 AM.

  9. #9
    bike whisperer Kimmo's Avatar
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    If you can't get one from Giant, you should be able to carve one from a lump of ally.

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    Senior Member igknighted's Avatar
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    Or... file away the excess and just use a clamp-type front derailleur instead (or even better... they make an adapter that clamps onto the seat tube to allow you to use a braze-on front derailleur on a bike without such a tab, so you wouldn't even have to buy a new front derailleur)
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  11. #11
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    Quote Originally Posted by igknighted View Post
    Or... file away the excess and just use a clamp-type front derailleur instead (or even better... they make an adapter that clamps onto the seat tube to allow you to use a braze-on front derailleur on a bike without such a tab, so you wouldn't even have to buy a new front derailleur)
    There is no excess to file off, why do people keep implying that this thing was somehow welded onto the frame?

  12. #12
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    One other possibility if you can't find a replacement "braze-on". If you remove it completely there shouldn't be any reason you can't use a clamp-on mount front derailleur. So you're in good shape either way.
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  13. #13
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    Quote Originally Posted by Dan The Man View Post
    There is no excess to file off, why do people keep implying that this thing was somehow welded onto the frame?
    The "excess" can the female threaded fittings that the tab bolts thread into and they may not be flush with the seat tube.

    If the seattube is round and of a standard diameter (1-1/8", 1-1/4" or 1-3/8"; 28.6, 31.8 or 34.9 mm respectively) a front derailleur clamp adapter is the way to go. If the seat tube is not round or of an non-standard diameter, you will have to replace the factory tab or fabricate a replacement.

  14. #14
    bike whisperer Kimmo's Avatar
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    There are a couple of thread inserts in the tube; it'd be a crying shame to employ a clamp-on rather than use them IMO.

    Also, they may foul the clamp if they're not flush.

  15. #15
    Senior Member igknighted's Avatar
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    Quote Originally Posted by Dan The Man View Post
    There is no excess to file off, why do people keep implying that this thing was somehow welded onto the frame?
    Easy, because if I assume there is nothing left and you try my suggestion (and there was something still there), it wont turn out well. If I assume that there might be something there and you simply skip that step if there isn't, then everything works out. You weren't specific in your OP, so I tried to cover as many bases as possible.
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  16. #16
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    The Giant dealer in town told me they could order one for around $20. I don't know if any of the other shops will have it. I found a picture of it from the Giant website:

  17. #17
    bike whisperer Kimmo's Avatar
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    Shwing!

    The one on my CFR1 was stainless plate; I always thought it was dumb how it wasn't ally.

  18. #18
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    Quote Originally Posted by igknighted View Post
    Easy, because if I assume there is nothing left and you try my suggestion (and there was something still there), it wont turn out well. If I assume that there might be something there and you simply skip that step if there isn't, then everything works out. You weren't specific in your OP, so I tried to cover as many bases as possible.
    I said in the original post and in a later post that it was bolted onto the frame (not welded). I am guessing that the confusion is that there are other types of derailleur mounts which are integral to the frame judging from comments about the frame being toast without rivets and having to file things.

  19. #19
    Old fart JohnDThompson's Avatar
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    Quote Originally Posted by FBinNY View Post
    One other possibility if you can't find a replacement "braze-on". If you remove it completely there shouldn't be any reason you can't use a clamp-on mount front derailleur. So you're in good shape either way.
    Unless you have some odd-shape (i.e. non-round) seat tube.

  20. #20
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    There is some kind of dent in the seat tube right where the derailleur goes. It looks like it's there to give the derailleur clearance. The paint is all shiny on it, so it's not frame damage, but the result is that the seat tube is not round.

  21. #21
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    Sigh.

    That 'dent' is meant to be there. Your bike has a replaceable front derailleur hanger. You have a source for one, buy it, install it and end thread.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

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