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  1. #1
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    Reputation: adarn's Avatar
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    Whoops... Wrong dropout angle

    Hey guys,

    So I'm working on frame #4 and I decided to get rid of some dropouts I've had around the shop. All I have left on this frame is the seat stays now. I somehow neglected to check the angle of the dropouts, and find my self in an interesting position.

    As you can see in the pictures, the angle is too small. Just brazing them on would definitely look funky, I think it might be ok structurally, what do you think?

    What should I do? chop 'em down more? new dropouts?







    thanks,
    Adam

  2. #2
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    Cut them out and start over with slightly shorter chainstays.
    Mark Farnsworth, Raleigh, NC
    http://farnsworthbikes.com

  3. #3
    WIGGLER
    Reputation: todwil's Avatar
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    I would scribe a line on the drop out of the desired angle and trim the Drops there looks to
    Be enough material for mod.
    PAYASO 36er.....Live the Circus

  4. #4
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    Adam,

    All is not lost, you just need to re-engineer the piece a bit.

    You will need to modify the existing dropout.

    Start by determining a terminus point for the end of your stays; from the center of your axle in the far forward position, measure up and forward a distance that you feel the natural angle for the stay should fall to and mark with a sharpee.

    With the terminus point known, mark a single line that represents the centerline of the seat stay as it travels to the main triangle. Take the diameter of the stay, divide it in half, then mark a cooresponding line above and below your centerline to represent the outer wall of the seat stay.

    You should now see where the tube should fall and how it will interact with the remaining dropout material.

    The Drive side dropout should be trimmed to allow for your slotted attachment approach and profiled to allow at least 12mm of internal extension or overlap.

    The brake side dropout is a bit more challenging. Your dropout will likely need to be trimmed so that you are removing material beneath the disc attachment back towards the axle to the same terminus of the drive side. This will force you to extend the slot in the stay up the tube, on it's superior aspect, so that the disc portion is encompassed by the tube that is running beneath it.

    All should be welded or brazed in, insuring you are pulling enough filler material in the stay to support the terminal end and the disc tab that is cantilevered above. You may also want to consider a support tube between the stays for longevity of the joint.

    I've attached a pic of a similar set up. Although I use a hooded dropout, you can see how the disc section is incorporated into the bisecting seat stay.

    Good luck,

    Rody
    Attached Thumbnails Attached Thumbnails Whoops... Wrong dropout angle-dropout-small.jpg  

    As requested by the MTBR gods, I am the voice of Groovy Cycleworks, check it out... http://www.groovycycleworks.com

  5. #5
    mtbr member
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    Cool,

    Thanks for the thorough response, Rody!

    That's sort of what I was thinking/hoping I could do.
    I'll post pics later this week when I get to it.

  6. #6
    Nemophilist
    Reputation: TrailMaker's Avatar
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    Hmmm...

    Sizable oversight, eh? Guess we've all got a few of those t-shirts!

    For those that like to see things before them, I like to use masking rape in place of tubes. From your ST terminus, and starting on the more limited brake side, stretch a piece of tape down as close to the axle center line as your brake hardware allows to mimic your eventual SS. You can reposition it as needed to try multiple options. You can even toss on your wheel and brake goodies to check for component clearances. Once you find the best compromise, you can mimic that (or for something different, not) on the drive side.

    When you get what you want, mark the DOs, trim them accordingly, and start slotting your stays.
    Attached Thumbnails Attached Thumbnails Whoops... Wrong dropout angle-fatbiketubesuppermocked.jpg  

    Attached Images Attached Images    
    Last edited by TrailMaker; 09-25-2012 at 04:42 AM.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  7. #7
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
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    Quote Originally Posted by adarn View Post
    Cool,

    Thanks for the thorough response, Rody!

    That's sort of what I was thinking/hoping I could do.
    I'll post pics later this week when I get to it.
    Should not be too complicated
    Whoops... Wrong dropout angle-newstay.jpg
    mtbtires.com
    The trouble with common sense is it is no longer common

  8. #8
    WIGGLER
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    Quote Originally Posted by shiggy View Post
    should not be too complicated
    Click image for larger version. 

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    +1!
    PAYASO 36er.....Live the Circus

  9. #9
    Randomhead
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    do the same bend in the says as in this other currently active thread, and you will be most of the way there:
    LINK

  10. #10
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    Go with the flow! What I mean is stick to the angle of the dropout and extend the seat stay past the seat post and up to the top tube creating a triple triangle like on GT bikes.

  11. #11
    mtbr member
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    I was thinking about the GT thing, but my butting marks wore off, so I couldn't be sure about how strong it would be. Here is what I ended up doing:


    Sorry, I realize thats not a great photo, but my camera is dead now.
    I did what Rody suggested on the non-drive side. I think it turned out pretty well. I'm excited about frame #4, I'll have to post more on it later.

    Thanks for the help!!
    -Adam

  12. #12
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    I'm no frame builder (never even tried welding) so forgive me if i sound stupid. On this drive side dropout could you takesome metal out so that the dropout blends into the seat stay?

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