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  1. #1
    Senior_Member2 diff_lock2's Avatar
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    Crank fell off while riding!

    So after some root/rock bashing with the bike (forest trails) i desided to get a drink from a store (lidl, german i think) well, after the forest ride (5km or so) im on the road on the way to this store... and my crank just flies off while pedalling! theres this hex bolt that holds it in and i guess that came loose... its a truvative firex... oh its the crank with out the chain rings... whats going on here??? should i check for somthing else that might come off?

    thanks, lol scared the ***** outa me, oh and now its knocking (i can feel/hear it) a bit every coplete cycle/pedal (revaloution)

  2. #2
    Keep on climbing
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    If the crank-arm fixing bolt was loose enough to allow the crank arm to come right off during a ride, then you've probably ruined the crank-arm / bottom-bracket interface as well. In other words, you might be able to put the crank-arm back on, but you'll never get it properly tight again -- it'll just keep working its way loose. That's probably what the "knocking" sound you refer to is -- you're flexing the crank-arm against the bottom bracket spindle and ruining it some more.

    If I were you, I'd toss the crank arm and bottom bracket and install new ones.
    "There is more to life than increasing its speed" -- Mahatma Gandhi

  3. #3
    Zippy Engineer Waldo's Avatar
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    A new BB is not usually necessary. Hardened steel spindle vs. alu crankarm is no contest. You should be able to snag a new arm relatively inexpensively at your local shop.

  4. #4
    Senior Member vw addict's Avatar
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    Call Truvative, they will gladly send you replacements. There was a tech bulliten about the Truvative splines interface and how to properly torque it. I have seen many come apart.

  5. #5
    Zippy Engineer Waldo's Avatar
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    Ah, good call. Forgot that they were hooking people up on those.

  6. #6
    The Rabbi seely's Avatar
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    Firex is most likely square taper, in which case the recall/warranty does not apply.
    commuter turned bike mechanic turned commuter (also a Velocity USA employee, but this is my personal account)

  7. #7
    cs1
    cs1 is online now
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    Quote Originally Posted by KevinF
    If the crank-arm fixing bolt was loose enough to allow the crank arm to come right off during a ride, then you've probably ruined the crank-arm / bottom-bracket interface as well. In other words, you might be able to put the crank-arm back on, but you'll never get it properly tight again -- it'll just keep working its way loose. That's probably what the "knocking" sound you refer to is -- you're flexing the crank-arm against the bottom bracket spindle and ruining it some more.

    If I were you, I'd toss the crank arm and bottom bracket and install new ones.
    +1

    Tim
    1999 Waterford RSE-11, 1995 Waterford 1200, 1989 Specialized Rockhopper Comp
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    1984 Specialized Stumpjumper, 1986 Specialized Stumpjumper and just way too many projects to list.

  8. #8
    Senior_Member2 diff_lock2's Avatar
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    well obiosly(sp) im going to check up on warranty, and then make the lbs take a look at it and see what went wrong... lol first my seat post and now the crank... maybe i should have gone with the hoss... lol

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