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  1. #1
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    Head tube OD not round

    Hi all,

    I recently bought a close out frame, Ventus sentier vrx, from chain reaction cycles. The head tube top and bottom OD is not perfectly round. There are visible indentations at the front close to the 12 o clock position. First 2 pics are the top, last 2 pics are bottom.

    Should I be concerned? Is this a big problem?

    I planned on ordering a cane creek 40 zs headset to use with this frame







    Sent from my iPhone using Tapatalk

  2. #2
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    Reputation: *OneSpeed*'s Avatar
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    If you're referring to the small dent on the outside of the headtube, I wouldn't worry about it. If you took accurate measurements of the ID of the headtube and it's out of round, that's a problem.

    Your ZS headset presses into the inner part of the HT and doesn't touch the outer. If the headtube isn't bent/ovalized, it's not a problem.
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  3. #3
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    Not a huge thing. It'll make pressing in the cups harder. You may want to have the LBS ream the ID to size.
    Do the math.

  4. #4
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    I have built up several bikes starting with the bar frame, and it's always a good idea to ream it properly. it's lousy that manufacturers don't do this from the factory. my Jabberwocky was so bad that the bottom cup would not press into the head tube flat at all until we reamed it. not all bike shops will have the right tools for that as they are expensive and are rarely used.

    I don't see the big deal with the OD though.
    Last edited by mack_turtle; 11-18-2018 at 10:42 AM.

  5. #5
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    That head tube has been faced already. You can see the machining swirls on the inside and face, so it’s stil parallel. The little ding on the outside edge may have distorted the tube diameter slightly but before recutting the inside try installing the the headset. It may still seat fine if a proper threaded press is used.

    Metallurgically, the molecules “remember” where they should be and can be coaxed back with pressure from the opposite side of the ding. Steel is better than aluminum but I doubt there’s a problem here.

  6. #6
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    Most likely those machining marks were there before the frame was welded, painted, or dented. I doubt that frame has been reamed.

    I do agree it's probably fine though.
    Rigid SS 29er
    SS 29+
    Fat Lefty
    SS cyclocross
    Full Sus 29er (Yuck)

    Stop asking how much it weighs and just go ride it.

  7. #7
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    Ummm, the ridge left by the bottom of the cutting tool after reaming is visible inside the head tube.

    Quote Originally Posted by *OneSpeed* View Post
    Most likely those machining marks were there before the frame was welded, painted, or dented. I doubt that frame has been reamed.

    I do agree it's probably fine though.

  8. #8
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    Quote Originally Posted by Reconnaissanceman View Post
    Ummm, the ridge left by the bottom of the cutting tool after reaming is visible inside the head tube.
    How do you know that was done after the frame was built?

    I'm not saying for sure I know it wasn't, I don't, I'm just speculating. I'm also not saying it was never machined, clearly it was.

    The reason head tubes and BB's (at least threaded ones) need to be reamed and chased is because most of that is done before the frame is welded and it often needs to be cleaned up prior to assembly due to warping or other imperfections.
    Rigid SS 29er
    SS 29+
    Fat Lefty
    SS cyclocross
    Full Sus 29er (Yuck)

    Stop asking how much it weighs and just go ride it.

  9. #9
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    Thanks for the info everyone. I took it to the lbs and got a new headset pressed in. They said the dents shouldn’t be a problem

    Head tube OD not round-img_0486.jpg Head tube OD not round-img_0487.jpg


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  10. #10
    No Clue Crew
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    Yep, as you say, long as the cups press in properly, I wouldn’t worry about it.
    Just like a raindrop, I was born to fall.

  11. #11
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    Well an aluminum headcup would likely deform to fit an oval headtube ID too ... they could both end up slightly oval

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