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  1. #1
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    dented top post and down post

    I ran into the back of a parked car going about 12 miles per hour. Luckily I survive more or less intact. My bike (C-dale Synapse) appeared unharmed. Two months and 1200 miles later I noticed dimples about the size of a pinky finger on the bottom side of both the top post and the down post, about two inches from the front connections. The rest of the frame appears to be unharmed.

    Question: How risky is it to continue to ride my bike? Am I tempting fate?

  2. #2
    Rumblefish jtarver's Avatar
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    You're tempting fate.
    1973 Crescent Pepita FG, 1987 Panasonic DX-4000, 1991 Trek 1400 FG, 1990's Gary Fisher Hoo-Koo-e-Koo SS, 1990's Denti Road Tech Five, 2009 Surly Long Haul Trucker

  3. #3
    DRF aka Thrifty Bill wrk101's Avatar
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    Quote Originally Posted by jtarver View Post
    You're tempting fate.
    +1 Retire the frame.

  4. #4
    Old fart JohnDThompson's Avatar
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    Quote Originally Posted by larrynem View Post
    I ran into the back of a parked car going about 12 miles per hour. Luckily I survive more or less intact. My bike (C-dale Synapse) appeared unharmed. Two months and 1200 miles later I noticed dimples about the size of a pinky finger on the bottom side of both the top post and the down post, about two inches from the front connections. The rest of the frame appears to be unharmed.

    Question: How risky is it to continue to ride my bike? Am I tempting fate?
    With a steel frame you could continue to ride it, albeit with handling changes due to the change in front-end geometry, but since you have an aluminum frame you're already tempting fate. Retire the frame.

  5. #5
    Great State of Varmint Panthers007's Avatar
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    Agreed. Remember Murphy's Law? You'd be doing 40 mph down a steep hill when it tears apart. The good news: There would be a cemetery at the bottom of the hill.

    How do you keep an idiot in suspense?

  6. #6
    Endurance junkie
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    This pic is useless without pics...

    You're describing buckling of the tubes caused by the crash. Aluminum is very unforgiving with fatigue compared with steel or Ti. It can simply snap when bent too much.

    It's better that the dimples are on the bottom of the tube rather than the top. If they were on the top, I'd guess the frame is going to go very soon. On the bottom it's from the original crash, and you probably didn't notice.

    It's not like it's going to assplode into a million pieces, but it's hard to say how much warning it will give when it goes. It might never go. Could be that you hear a crack and the down tube splits halfway. Could be you hear a crack and both tubes split almost instantly. Aluminum is funny that way. The high strength alloys don't like to bend.
    Last edited by twentysixtwo; 09-06-09 at 08:51 PM.
    '93 GT Pantera (childseat and trailer duty)
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  7. #7
    Great State of Varmint Panthers007's Avatar
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    Semantics. Aluminum has very little tolerance to bends and dimples. It WILL go - if you ride it. And in the worst way there is. If ol' Murphy knows his a** from his elbow. Retire the frame - yesterday.
    How do you keep an idiot in suspense?

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