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  1. #1
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    Reputation: gonzo's Avatar
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    niner carbon fork defective race fit

    I contacted because my carbon fork had a little play at the race.

    After inspecting the fork stem, the diameter where the race fits was a bit under sized.

    Niner said they have never seen that before that they would sell me a replacement because I was not the original buyer.

    Just wanted to see if anyone has had this problem since all manufacturers deny having quality control problems...

    thanks

  2. #2
    transmitter~receiver
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    first i've heard of it. interference fit parts rarely get to customers if they're out of spec, but I suppose it can happen. Did the person you bought it from have this issue?
    what does, "inspecting the fork stem" mean? did you use a caliper to check the dimensions?
    put a caliper to both the race and fork crown and see what's up.
    could be your race is oversized.
    if your fork has a straight steer tube the crown race seat diameter should be:
    30.015(+0.06)mm
    and the race ID should be:
    29.98(-0.05)mm

    if your fork is tapered the crown race seat diameter should be:
    39.79(+0.06)mm
    and the race ID should be 39.76(-0.05)mm

    FYI: interference fit tolerance is usually expressed not as +/- but as target value with tolerance that increases interference
    link
    Last edited by meltingfeather; 04-12-2013 at 12:14 PM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  3. #3
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    Quote Originally Posted by gonzo View Post
    I contacted because my carbon fork had a little play at the race.

    After inspecting the fork stem, the diameter where the race fits was a bit under sized.

    Niner said they have never seen that before that they would sell me a replacement because I was not the original buyer.

    Just wanted to see if anyone has had this problem since all manufacturers deny having quality control problems...

    thanks
    I have a Niner carbon fork with a straight steerer that came on a used SS I bought a year ago.

    The bike had a Hope headset, which uses a split crown race.

    When I went to put on a King headset, I found the crown race was a bit loose.

    Brought it to my LBS for help...

    LBS ended up getting me a slightly undersized crown race (King makes these) which solved the problem.

    When I posted it here on mtbr (maybe in the Niner forum? not sure ... ) nobody had heard of it happening either.

    SPP
    Rigid.

  4. #4
    Bro Mountainbiker
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    I had the same problem.

    When I first bought the fork, the crown race was fairly easy to install with tools.

    After 2 years of use, the crown race wore loose on the crown race seat.

    I ended up laying up a layer of carbon around the area, then sanding that down until A crown race would fit snug again.
    Raised in a Chicken-Coop by Chickens

  5. #5
    mtbr member
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    Great information:
    I measure the race base. This is the variation I got
    29.9
    29.7
    Looks like its under spec. When I first installed a brand new king race it seemed to go on pretty easy, but had NO play.

    I had several other king race rings and tried them but they all had play.

    Just wondering if this is a niner quality issue getting out of the factory or????

    I know manufacturers don't make quality issues known to the public.

  6. #6
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    Quote Originally Posted by gonzo View Post
    I know manufacturers don't make quality issues known to the public.
    One company you cannot accuse of hiding quality issues is Niner. Think back to the frame recall, they went way above and beyond what was required.

    Niner official - Jet 9 safety recall
    Last edited by driver bob; 04-13-2013 at 09:19 AM. Reason: added url

  7. #7
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    niner carbon fork defective race fit

    Hmmm. My fork keeps loosening. My LBS seems to think its the compression plug moving.

  8. #8
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    Quote Originally Posted by DrDon View Post
    Hmmm. My fork keeps loosening. My LBS seems to think its the compression plug moving.
    Mine has been doing the same thing and when I pulled the stem off to investigate the compression had plug definitely moved upwards. The compression plug is not what holds everything tight though, it is only used to set the pre-load on the bearings, so it moving is more a symptom than the cause. I think the real issue is the stem has a hard time getting enough bite on the carbon steerer and starts slipping upwards pulling the compression plug up along with it. Niner supplies carbon paste to help provide some extra grip between the stem and the steerer so I would try that if it hasn't been used.

  9. #9
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    The stem slipping was mentioned as a possible culprit. I put more friction past on it. I put friction paste on the compression plug and locktited all the bolts, although I think Niner recommends against doing so. I may even locktite the compression plug, and of course I will be responsible for any consequences. Origin 8 has a new funky looking fork out with a hefty weight limit and a straight steerer tube. I could of sworn that Whiskey had a straight tube fork at one time. I may go with an On-One fork and be done with it. I do have a older WaltWorks fork which has a nice feel, but is sort of a tank.

  10. #10
    Drinkin' the 29er KoolAid
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    Quote Originally Posted by DrDon View Post
    The stem slipping was mentioned as a possible culprit. I put more friction past on it. I put friction paste on the compression plug and locktited all the bolts, although I think Niner recommends against doing so. I may even locktite the compression plug, and of course I will be responsible for any consequences.
    Honestly, I don't think friction paste nor locktite would be of any value on the compression plug given its role is to set initial pre-load *before* you tighten the stem bolts. After the stem is tightened the compression plug is basically just along for the ride and perhaps re-enforcing the steerer tube against any crushing force from the stem. I think the loosening is mostly due to a rigid fork passing a lot more impact force into the stem/steerer tube interface than a suspension fork would. It is certainly annoying to have it coming loose as I tend not to realize it has done so until the end of the ride which means the headset pieces were being allowed to move around for god knows how long during the ride. This can't be good for the headset and could quite possibly lead to some of the wear on the crown race seat area that others are reporting.
    Last edited by kwarwick; 04-14-2013 at 08:16 AM.

  11. #11
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    niner carbon fork defective race fit

    Quote Originally Posted by DrDon View Post
    I put friction paste on the compression plug and locktited all the bolts, although I think Niner recommends against doing so. I may even locktite the compression plug, and of course I will be responsible for any consequences.
    Locktite isn't going to do anything for you, on the stem or the plug.
    It's a clamping force problem, which will only be solved by bolt torque. Of course your bolts with Locktite on them won't register correctly on a torque wrench, so just tighten them by feel a little at a time with riding in between until you determine they are tight enough.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  12. #12
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    niner carbon fork defective race fit

    Any thoughts about using a downhill specific headset? Would the only benefit be prevention of ovalizatio?

  13. #13
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    I'm having the same issue.

    The crown race from a Cane Creek FORTY headset is too loose around the straight steerer tube. The steerer tube measures 29.46mm and it should measure 30.0mm.

    This is a new Niner fork which was not previously used or installed.

  14. #14
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    This happened to my Niner fork too. I called Niner about it and they sent me a replacement. Good luck. I tried two different headsets before realizing the fork was the problem.
    The unexamined life is not worth living - Socrates
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