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  1. #1
    Single Speed Junkie
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    Cold setting a frame

    Wondering if there is a reasonable means of cold setting a Ti frame. Rear drops measure 126.5mm where spec should be 135mm. Thinking of taking a piece of threaded rod and start opening them up till they rest at 135mm. Want to keep the frame straight in the process.

    Waited way to long for this frame for it to be out of spec or crooked.

  2. #2
    Moderator Moderator
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    Whoa.

    You should get a new frame. If the DOs are ~10mm out of spec, what else is wrong that you can't see or easily measure?

    But to answer your question, sure, you can probably bend it out. Threaded rod would work (wear safety glasses!) or if you're strong, you may be able to just put a foot on the inside of one dropout and lift up on the other one. Thanks to the magic of physics, you'll be applying the same amount of force to each side. Depending on the size of the tubing on the rear end, though, you may or may not be able to do it. Ti is *insanely* hard to bend.

    -Walt
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  3. #3
    RCP Fabrication
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    Did it get crushed in shipping? Occasionally, on frames with beefy chainstay bridges they spring in some, but 10mm?? Contact the builder, if its going to be cold set have it done by the builder, or at least okayed by the builder, so if it fails down the road it's not on your hands.

    Edit: If you do choose to cold set it, be prepared to spread the frame 2-3 times the difference it needs to go to put it where you want.

  4. #4
    mtbr member
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    Crux,

    Ti frames can be reasonably cold set, however...

    ti takes a much greater deflection to achieve small results and it reaches it's yield point with sudden, acute results.

    I would not suggest attempting to reset the rear triangle yourself, for if it does fail, you've no one but yourself to hold accountable. An experienced ti builder will have a feel for the correct amount of force required and will have more accurate means to measure success and accuracy. Best to send her back if it's an issue.

    To give you an idea of ti's bendy, pulley nature, I commonly space my rear triangles out to 145mm before setting the seat stay bridge, allowing the welding of the piece to naturally pull the dropouts into spec. This allows me to hit 135mm within +/- .5mm consistently.

    cheers,

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

  5. #5
    Single Speed Junkie
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    Thanks for all the help. I talked with the builder yesterday discussing the matter. He had confidence that I could cold set easy enough. If it did fail then I'd just send him the frame and forget about the build. Long story short. I placed the frame in the wood vice on the side of my table with two upright posts oddly enough spaced at 120mm to begin with. Then I backed out the vice counting the number of turns each time. Then measuring the frame seeing where the final reading was. Took a few times to get it out to its final resting spot of 135.2mm. Afterwards I double checked that the drops were parallel and much to my shock they were.

    Your right Ti does need to be bent quite a bit before it will hold at a given measurement. For most I would not recommend doing this but felt comfortable with the tools in the shop to give it a try and with builders approval in covering the frame. Now need to finish building up the bike

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