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  1. #1
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    Is this normal wear and tear

    what could've caused this? its a stock shimano hub from a 06 stumpjumper.
    "Nuke'em!"

  2. #2
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    Could be a casting defect? I'm not sure of Shimano's warranty policies, but it is unlikely the hub is still under warranty. Luckily Shimano hubs are relatively inexpensive.

    When did the damage occur? Riding, removing or installing disc? Did the bolts actually come undone? I've seen my share of cracked hubs, but I've never seen so many bolt posts fail simultaneously. Could the damage have occured gradually (first one bolt hole, then another etc..)?

  3. #3
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    i really couldn't tell you the details. only that the damage occurred while my nephew was popping wheelies. this would've been my 4th year riding this hub...
    "Nuke'em!"

  4. #4
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    could have been overtorqued way back when and the extra stress just blew them out.

  5. #5
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    Quote Originally Posted by jeffscott View Post
    could have been overtorqued way back when and the extra stress just blew them out.
    In my experience the rotor bolts strip out if they are being torqued too much. It would be interesting to check and see if the axle is broken too.

  6. #6
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    Rotor bolts loose and finally gave up, the hub could not take the rocking back and forth,also looks like the threads start too deep in the hub. Notice how one did not tear out. Lets see the bolts.

  7. #7
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    Quote Originally Posted by IntensevCare View Post
    Rotor bolts loose and finally gave up, the hub could not take the rocking back and forth,also looks like the threads start too deep in the hub. Notice how one did not tear out. Lets see the bolts.
    I'm going with this one...

  8. #8
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    I saw something similar happen to a friend's hub when his mecahnic failed to Loctite the bolts, causing a few of them to back out and putting far too much stress on the remaining bolts.

    -Pete
    I can barely get my mouth around it.

  9. #9
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    Quote Originally Posted by Pedalphile View Post
    I saw something similar happen to a friend's hub when his mecahnic failed to Loctite the bolts, causing a few of them to back out and putting far too much stress on the remaining bolts.
    I'm liking my centerlock rotors more and more.

  10. #10
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    I agree with IC as far as loose rotor bolts. The first one to go was the hole with the lateral break. It broke in the direction of torque on the rotor when the brake is applied. The two following simply cascaded in sequence due to the additional stress placed on them.

    As far as the thread depth goes, hard to say. All most all manufacturers will thread a blind hole a few mm's deeper than the length of the bolt intended to be threaded into them. This allows for variations in manufacturing tolerances between bolts. The last thing you need is for a bolt to bottom out in a blind hole.

    I've only seen one other failure like this. It was a 3 year old bike a customer brought into the shop, and it was the front hub not the rear. Typical "just riding along" story. But during the ensuing conversation he admitted that in doing his own maintenance he'd never once checked the rotor bolts. That hub showed pretty much the same failure pattern as in the OP's picture. One hole fractured laterally and the following two fractured almost vertically.

    So a great argument for checking rotor bolts regularly and manufacturer torque specs I think.

    So it's new hub or new wheel time unfortunately. As anlin noted the hub is out of warranty, Shimano warranty is for 1 year after date of purchase. You could check around and see if there were any known issues of this type with that specific model hub. But being 4 years old you'd be exceedingly lucky if Shimano would do anything for you.

    Bummer that it happened though.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  11. #11
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    Yeah I bet one or two of the bolts worked lose, then one of the holes cracked, then they all went.

    Check the surface where the cracks are, you can tell if one of the cracks or part of one of the cracks is older by the tarnish. The fresh cracks will be nice and clean while older cracks will be discolored.

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