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  1. #1
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    cracked top tube, please give me your opinion

    Hey all,

    I sent this question out to KHS this afternoon as well, and wondering what those of you with experience here thought. Here's the email I sent out:

    "I own a flite 900 road bike and recently set it up on a bike stand to make some repairs. The clamp was designed to clamp onto the toptube. As I started locking it down, I heard two cracking noises and so I stopped. The force I applied at that point was very small. I inspected the area and found two long (3-4") but extremely thin (almost unable to see) hairline cracks on the very top of the top tube. I was wondering how serious this damage is, and if it was possible that i just cracked the paint and not the frame."

    and here's a close up picture:



    okay thanks guys for your time, really hoping i can ride again tomorrow.

  2. #2
    Fossil Lurch's Avatar
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    What is the frame material? How loud were these cracking sounds? It's hard to imagine paint making much noise when it cracks, but then it's odd to crack a frame tube with a stand clamp also.
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    And that is why I always clamp to a seat post. Wouldn't own a stand that works any other way

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    You Know!? For Kids! jsharr's Avatar
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    Clamps and carbon fibre do not get along well. Sounds to me like you probably damaged that frame. I would be leary of riding it until Flite had checked it out. Good Luck.
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  5. #5
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    It might be worthwhile to sand or scrape the paint away in the area where the crack lines appear. This would tell you if the crack is only skin deep or all the way to the bone. An old trick to keep crack lines from growing longer is to drill a small hole at each end of a crack. If the crack is in the frame material, you might be able to reinforce the tube by wrapping it in a sleeve made from a couple of layers of fiberglass, or even carbon fiber. Check with an auto body shop that uses carbon fiber to see if they can do it for you. This may not look totally cool, but it could be regarded as a personal customization. In the end this would not be a lot different from American Indians wrapping a cracked ***** stock with rawhide to repair and reinforce it.
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  7. #7
    Mad bike riding scientist cyccommute's Avatar
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    Quote Originally Posted by twobikes
    It might be worthwhile to sand or scrape the paint away in the area where the crack lines appear. This would tell you if the crack is only skin deep or all the way to the bone. An old trick to keep crack lines from growing longer is to drill a small hole at each end of a crack. If the crack is in the frame material, you might be able to reinforce the tube by wrapping it in a sleeve made from a couple of layers of fiberglass, or even carbon fiber. Check with an auto body shop that uses carbon fiber to see if they can do it for you. This may not look totally cool, but it could be regarded as a personal customization. In the end this would not be a lot different from American Indians wrapping a cracked ***** stock with rawhide to repair and reinforce it.
    Probably not the soundest advice. It doesn't look like there is much paint to scrape off the frame (probably a clear coat) and, from what I've read about carbon fiber, the outer layer can be rather cosmetic anyway...it's the inner layers that do the work. Scraping the frame down to the fiber would probably damage it further anyway.

    As for drilling a hole to stop a crack propagation, that's probably not a good idea either. It would certainly void the frame warranty unless KHS suggests it.

    To stea1thviper: I hate to say this but the frame is probably toast. And, since you did it during a repair, they probably won't warrantee it. You'll probably find somewhere in the owners manual that you shouldn't clamp the frame in a repair stand. KHS may take mercy on you and will give you a deal on a frame. Don't get mad at them. You crunched it.

    It's too bad but the difference between an experienced mechanic and a master mechanic is the dollar amount of the stuff the master mechanic has ruined. Take a lesson from this and go forward.

    Bummer. And I certainly wouldn't take the bike out for a ride.
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    It looks like you just found out the hard way that top tubes on modern bikes are incredibly thin and should never be used for clamping.

    What brand of repair stand was it? Although most stands can clamp to the top tube, I don't know of any that are specifically intended for clamping there, as you suggest. (Although one brand, the ULTIMATE repair stand, supports the top tube, it doesn't clamp down on it with any squeezing pressure, per se).

    If the instructions that came with your repair stand specifically tell you to clamp the top tube, you may have cause to complain to the manufacturer of the repair stand. (But I'm betting the instructions would never say to do that).

    Bob

    P.S. I'm afraid to say that I think your frame is toast.

  9. #9
    Senior Member capwater's Avatar
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    Bummer, frame is toast. DO NOT RIDE IT.

    I crashed a Giant TCR in a crit a couple of months ago and thought it was OK until I noticed a couple of similar cracks 2 weeks later. Giant rep hooked me up with a new frame after a quick look at the cracks to ascertain it's fate. Yup, clamps go on seatsposts, not frame. Get a cheapo AL post to use, never use a carbon post because of the obvious similar fate to your top tube.

  10. #10
    Cycling Skier songfta's Avatar
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    Quote Originally Posted by Bobby Lex
    P.S. I'm afraid to say that I think your frame is toast.
    Calfee Design can repair most carbon fiber frames, if you're really attached to your Flite and want to keep it in service.

    Otherwise, you're likely looking at replacement.
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  11. #11
    The Red Lantern Rev.Chuck's Avatar
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    Calfee does carbon frame repair. We sent out a Roubaix that had a damaged top tube, they fixed that and also did a pretty decent finish match.

    http://www.calfeedesign.com/

    edit: songfta beat me to it.
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  12. #12
    My bike's better than me! neil0502's Avatar
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    Agree with those that say that--in its current state--we're talking toast.

    Evaluate your repair options--either through Calfee or if KHS will have mercy on you.

    Buy the cheapest seatpost you can that fits your bike and use IT for clamping in the future.

    Sorry, Dude. I feel your pain, too....

  13. #13
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    thanks for all the comments everyone. i agree on second thought that paint probably doesn't make that cracking noise. i learned a hard lesson though. it's surprising how little force is required to create cracks like that. And I will def always clamp my bike to an Al seatpost now. Unfortunately I don't have more than $50 to spare on a fix/replacement at the moment. But I will be able to get ahold of a friend's old 80's schwin road bike that fits me with some minor adjustments, which I can ride until I'm able to do something about my own frame. I'm mostly concerned about keeping up in training hours, so long as I have a bike I'm ok for now. I really did like that frame though...

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