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  1. #1
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    Caution;  Merge;  Workers Ahead! Rotor mounting bolts came off - how do I prevent this?

    I replaced both wheels but kept the rotor from old wheel. I put the bolts into the new hubs pretty tight. Fast forward 2 months, 4 bolts came off of rear rotor and are missing. I'm not sure when or how (all at once or one by one) they came off but it's a scary thought if they all came off in the middle of riding. The front rotor is fine but I'm wondering why the rear, where it takes less stress, this problem occurred. These bolts have blue coating on the thread which I think is there to keep it from loosening (?).

    What could possibly be the culprit and what can I do to prevent it in the future? Thanks.

  2. #2
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    One word: Threadlock.
    Use the blue stuff.

  3. #3
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    Like the-one1 said. Blue Loctite. DO NOT USE THE RED STUFF!!!!!
    2010 Santa Cruz Blur LT2, Fox TALAS Terralogic, Fox RP23 shock, SRAM X0, XTR Trail Brakes, Stans/Chris King Wheelset

  4. #4
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    Get a torque wrench to correctly tighten the bolts.

    Give your bike a quick once over before every ride, you might have caught it at the first bolt backing out.

    Now that it has been used with the bolts loose, you may have wallowed out the bolt holes in the hub. If this happened, the bolts may never stay tight and the hub would need to be replaced.

  5. #5
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    Quote Originally Posted by gmcttr
    Now that it has been used with the bolts loose, you may have wallowed out the bolt holes in the hub. If this happened, the bolts may never stay tight and the hub would need to be replaced.
    Now that I replaced the bolts with new ones, I think (and hope) that the used bolts were the culprits. I went to a local bike shop in search of Loctite but they didn't have any so I picked up a new set of bolts. These have the blue coating already on and the guy says those coatings help to keep the bolts in place. I took out the old ones and while putting the new bolts on, I noticed something different from the previous rotor installation. The new bolts have much more resistance going in due to the fresh blue coatings on the thread. The used bolts (w/ worn out blue coating) didn't have that much of resistance as I recall and I think that may be why they came off easily. A rookie mistake perhaps?

  6. #6
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    Quote Originally Posted by Optimizer
    Now that I replaced the bolts with new ones, I think (and hope) that the used bolts were the culprits. I went to a local bike shop in search of Loctite but they didn't have any so I picked up a new set of bolts. These have the blue coating already on and the guy says those coatings help to keep the bolts in place. I took out the old ones and while putting the new bolts on, I noticed something different from the previous rotor installation. The new bolts have much more resistance going in due to the fresh blue coatings on the thread. The used bolts (w/ worn out blue coating) didn't have that much of resistance as I recall and I think that may be why they came off easily. A rookie mistake perhaps?
    Used bolts need a new application of threadlock. Get it at an auto parts store.
    mtbtires.com
    The trouble with common sense is it is no longer common

  7. #7
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    Threadlock is not bike specific. You can pick it up almost anywhere; hardware stores, auto parts stores, wal-mart, sears, grandma's house....etc.

  8. #8
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    Thanks for the tips.

  9. #9
    dru
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    Why don't you have the metal lock tabs that come with the hub/rotor? They cover two bolts and guaranteed stop the bolts from loosening. Like gmcttr said, have quick look a little more often than you do!

    Drew
    occasional cyclist

  10. #10
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by dru
    Why don't you have the metal lock tabs that come with the hub/rotor? They cover two bolts and guaranteed stop the bolts from loosening. Like gmcttr said, have quick look a little more often than you do!

    Drew
    Shimano is the only company that does that.
    mtbtires.com
    The trouble with common sense is it is no longer common

  11. #11
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    Mine is Avid.

  12. #12
    Waiting for my Obamabucks
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    Blue Loctite is available at Pep Boys, Autozone, probably Walmart, etc. The resistance you felt was the new blue loctite coating. I own and maintain my dirt bikes, so I go through a blue loctite bottle once a year. I use the stuff on my cranks because they seem to loosen up without it.
    2010 Santa Cruz Blur LT2, Fox TALAS Terralogic, Fox RP23 shock, SRAM X0, XTR Trail Brakes, Stans/Chris King Wheelset

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