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  1. #1
    g3h6o3
    Reputation: PissedOffCil's Avatar
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    Reaming 30.0mm seat tube to 30.9mm

    Hello,
    I dropped Norco an e-mail about this but didn't get an answer so I'll take my chances asking here.

    I have a 2006 Norco Six as my AM bike. The bike has a 30.0mm seat tube and I'd like to use a dropper seat post but most of them come in 30.9mm and over. I read of a guy on a Transition frame reaming it down to 30.9mm and thought of doing the same. Does any knowledgable person around here ever tried this and can report on how it's holding?

    Thx
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  2. #2
    mtbr member
    Reputation: GTscoob's Avatar
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    That is a lot of material to remove from already thin aluminum tubing.

    Why not go with one of the available 27.2 dropper posts and run it with a shim?

  3. #3
    g3h6o3
    Reputation: PissedOffCil's Avatar
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    I'm not sure if you are familiar with the frame and I'm not trying to discredit you but this frame has pretty hefty tubing. Comparing it to other frames I have owned the seat tube seemed massive. It was sold as a AM/FR frame after all but it isn't really used as such.

    With that said, I wouldn't move on without a confirmation from Norco, it's simply not worth it but was interested in other peoples experience with weird size (non standard) tubing.
    Check out my SportTracks plugins for some training aid software.

  4. #4
    mtbr member
    Reputation: masterofnone's Avatar
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    I'm not a fan of "altering" frames and components, there's infinite ways to f#%@ up here and you put your family jewels at risk if the seatube fails because of your efforts.. Any manufacturer is going to tell you you'll void any warranties and it's potentially dangerous. Like gtscoob said, just get a smaller post like a gravity dropper and shim up as needed.

  5. #5
    T.W.O.
    Reputation: mimi1885's Avatar
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    What adj post do you have in mind? On that Norco you'd also have to worry about the length of insertion as well. Too much post exposure at the bottom it would hit the shock.

  6. #6
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    It's less than 1/32" off the tubing wall...I wouldn't worry about it, but it will still likely void the warranty.

    You want to make sure to make a smooth dimensional transition and not a sharp corner on the inside of the tube or it will crack there. A better idea would be to swage it...as if that tooling were even available.

    Theoretically, it's easier to turn down the post if it's thick enough.

  7. #7
    mtbr member
    Reputation: mitzikatzi's Avatar
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    Some would say don't do it.

    frame-building/seat-tube-reaming
    Duct tape iz like teh Force. It has a Lite side and a Dark side and it holdz the Universe together.

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