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  1. #1
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    Drilling a 6.6 for a stealth dropper?

    Looking to get a new dropper for my 6.6 and like the idea of having a stealth cable/hose. Has anyone drilled their frame to take a stealth? If so, where did you drill and how did you protect the hose?
    Cheers
    Steve

  2. #2
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    Hope

    I think the issue might be creating a stress point in the aluminum seat tube. Perhaps you could find some sort of steel grommet to put on the hole and then a nylon or rubber grommet in the steel grommet to protect the hose.

    My thinking is that the steel grommet might support the stress that might be caused by altering the seat tube.


    Note: I've never done anything like this, so you should definitely take my advice.

    ;-)

    PS - Aluminum frames often have water bottle bosses installed where you'd put a cable entry point, and they have steel inserts. I've never seen a frame collapse at the site of a bottle mount. This project isn't too different. Besides, if your 6.6 hasn't broken yet, it probably will soon and you ain't getting any spare frame triangles for it.

  3. #3
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    Just shooting from the hip - If you have openings in the bottom bracket for both the down tube and seat post most of the work is done. As far as drilling a hole in the down tube for the exit near the handlebars - it will weaken the tube and cause a stress riser.

    If you try it - stay a good distance away from any welds (local thermal hardening causing more brittle material), and have the final hole milled in at an angle (machinist with a bridgeport) instead of drilled straight. Debur internally and chamfer externally...

  4. #4
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    Thanks guys. Good points made!
    I'll have a look to see if there is openings in the BB/ST area as that would make life easier. I'm a CNC programmer so have access to machines to do an angled hole.

    Could use something like this to keep the cable safe: Name:  6mm-gromet.jpg
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    Intense 6.6

  5. #5
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    Quote Originally Posted by SSearchVT View Post
    Just shooting from the hip - If you have openings in the bottom bracket for both the down tube and seat post most of the work is done. As far as drilling a hole in the down tube for the exit near the handlebars - it will weaken the tube and cause a stress riser.

    If you try it - stay a good distance away from any welds (local thermal hardening causing more brittle material), and have the final hole milled in at an angle (machinist with a bridgeport) instead of drilled straight. Debur internally and chamfer externally...
    I'm willing to bet that today's aluminum post-weld heat treatment schedule is no different (or not significantly different) from that used on a 6.6 from a few years ago. The metallurgy hasn't changed much.

    So, assuming I know anything (debatable), you could look closely at an intense frame from TODAY, say a tracer 275 and copy/match that installation.

    The question is if Intense drills holes for droppers BEFORE or AFTER post-weld heat treatment (called annealing) and if that matters to stress at that area.

    Annealing is done to modify and control the grain structure of the metal and to "heal" damage from welding. I would think that if you are CAREFUL in drilling and milling, that you would not add any stress.

    YMMV.

    I'm curious since I have a Tracer VP (updated 6.6?) and currently run an external dropper cable.

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