An extreme example, but...

EKE_38BPM
EKE_38BPM Posts: 5,821
edited August 2011 in Commuting chat
this kind of failure shows why I don't want a carbon framed bike.

Maybe I'm wrong, but I'm no longer a fan of carbon. I don't think a metal framed (ideally Ti) would have failed so suddenly.
FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
FCN 4: Planet X Schmaffenschmack 2- workhorse
FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

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Comments

  • se-po
    se-po Posts: 47
    Lol 107 mph, not fan of that speed either :-)
  • notsoblue
    notsoblue Posts: 5,756
    Yeah, the next time I plan on riding down a volcano at 107mph, I'll be sure to do it on a Ti frame ;)
    FCN 4 PX SL Pro SRAM Red
    FCN 8 Scott Sportster '05
  • First.Aspect
    First.Aspect Posts: 16,999
    I bet he got splinters from that carbon fibre, as well.
  • desweller
    desweller Posts: 5,175
    EKE_38BPM wrote:
    this kind of failure shows why I don't want a carbon framed bike.

    Maybe I'm wrong, but I'm no longer a fan of carbon. I don't think a metal framed (ideally Ti) would have failed so suddenly.

    You are wrong.

    If you hit something hard enough, it breaks suddenly and without warning. Whatever it's made of.
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  • Jrandell
    Jrandell Posts: 20
    EKE_38BPM wrote:
    this kind of failure shows why I don't want a carbon framed bike.

    Maybe I'm wrong, but I'm no longer a fan of carbon. I don't think a metal framed (ideally Ti) would have failed so suddenly.

    are you planning on riding down the side of a volcano at 107mph??
    :wink:
    Boardman Team Carbon 2010
  • tx14
    tx14 Posts: 244
    EKE_38BPM wrote:
    this kind of failure shows why I don't want a carbon framed bike.

    Maybe I'm wrong, but I'm no longer a fan of carbon. I don't think a metal framed (ideally Ti) would have failed so suddenly.
    if something isn't used properly it will fail. no matter what it's made of.
  • First.Aspect
    First.Aspect Posts: 16,999
    tx14 wrote:
    EKE_38BPM wrote:
    this kind of failure shows why I don't want a carbon framed bike.

    Maybe I'm wrong, but I'm no longer a fan of carbon. I don't think a metal framed (ideally Ti) would have failed so suddenly.
    if something isn't used properly it will fail. no matter what it's made of.
    Yes, he shoudn't have ignored the "not suitable for offroad use" sticker.
  • tx14
    tx14 Posts: 244
    First Aspect wrote:
    tx14 wrote:
    EKE_38BPM wrote:
    this kind of failure shows why I don't want a carbon framed bike.

    Maybe I'm wrong, but I'm no longer a fan of carbon. I don't think a metal framed (ideally Ti) would have failed so suddenly.
    if something isn't used properly it will fail. no matter what it's made of.
    Yes, he shoudn't have ignored the "not suitable for offroad use" sticker.
    go ride a steel or ti alloy bike down a mountain at 170km/h, the bike will fall apart, not just the frame.
  • walkingbootweather
    walkingbootweather Posts: 2,443
    This was his lightweight summer bike. His world record is 138mph in the snow at Les Arcs. If I could commute at this speed I'd get to work in less than 5 mins!!!
    Nobody told me we had a communication problem
  • MaxwellBygraves
    MaxwellBygraves Posts: 1,353
    Carbon is tougher than you think.
    "That's it! You people have stood in my way long enough. I'm going to clown college! " - Homer
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    MaxwellBygraves wrote:
    Carbon is tougher than you think.

    No it isn't.

    Carbon is strong in the direction is has been designed to be strong in, but quite weak in other directions. A carbon tube (such as a part from a bike frame) can cope well with the normal stresses of road riding, but lean it against a wall and anything could happen.
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • desweller
    desweller Posts: 5,175
    EKE_38BPM wrote:
    MaxwellBygraves wrote:
    Carbon is tougher than you think.

    No it isn't.

    Carbon is strong in the direction is has been designed to be strong in, but quite weak in other directions. A carbon tube (such as a part from a bike frame) can cope well with the normal stresses of road riding, but lean it against a wall and anything could happen.

    That's true if your CFRP frame is made with unidirectional cloth, but the vast majority are made with a weave or chopped mat. It's just plain untrue to state that anything could happen if you leant it against a wall.

    As far as I can see most CFRP frame manufacturers just design their frames as if they were using GRP anyway.
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  • dcurzon
    dcurzon Posts: 290
    i think he would have gone faster if he'd bothered his arse to actually pedal
    B'Twin Sport 1
    FCN 7 =4, +2(non cycling clothes) +1(beard)
  • mudcow007
    mudcow007 Posts: 3,861
    maybe it got wet just before the ride?
    Keeping it classy since '83
  • rolf_f
    rolf_f Posts: 16,015
    DesWeller wrote:
    That's true if your CFRP frame is made with unidirectional cloth, but the vast majority are made with a weave or chopped mat. It's just plain untrue to state that anything could happen if you leant it against a wall.

    The weave only helps you if you've already made a hole in the carbon fibre - it doesn't actually make it stronger in the first place. It's usually only cosmetic anyway and underlain by unidirectional cloth.
    Faster than a tent.......
  • bails87
    bails87 Posts: 12,998
    My MTB is carbon, I've been flying down trails at 30mph when I've heard *THUMP* as a rock has been launched up into the downtube.

    Fortunately it's reinforced with kevlar, and there wasn't even a scratch on it.

    Where's that video of someone smashing up a Cannondale MTB with a lump hammer?

    Aha, there it is.
    MTB/CX

    "As I said last time, it won't happen again."
  • Headhuunter
    Headhuunter Posts: 6,494
    My carbon road frame has been through the wars and is still fine. I fell off onto the drive side and thought I had cracked it a while back but it's held. Another time I was hammering something in the garden, really putting some welly into it and the head of the hammer flew off and of all the things behind me it could have hit, it smacked straight into the carbon frame. Left a chip in the lacquer but otherwise it's fine. Last weekend I was on a club ride, close behind another rider when I went straight into a DEEP pothole. I thought I'd destroyed my wheels and forks it was such a bang, but both seem fine, no chips to the lacquer of the forks which would be a telltale sign of terminal damage.

    I think carbon gets a bad press, every now an then a thread on this site pops up with some rubbish about it melting in the rain etc. If it was really dangerous, bike manufacturers wouldn't be allowed to use it. The only thing is that I have heard that when it goes, it goes suddenly and its resistance to 2nd impacts is not good, whereas ti and steel etc will bend and give way more slowly....
    Do not write below this line. Office use only.
  • bails87
    bails87 Posts: 12,998
    Headhuunter wrote:
    Another time I was hammering something in the garden, really putting some welly into it and the head of the hammer flew off and of all the things behind me it could have hit, it smacked straight into the carbon frame. ...
    Sorry, but :lol:

    I also plughed through a deep pothole at about 30mph (the dangers of drafting :oops:) on my Ribble. The impact was so sharp that it winded me, but the frame, forks, wheels were all fine.

    Eke: I trust you won't be using these new fangled spoked wheels, just in case this happens: p4pb3804372.jpg
    MTB/CX

    "As I said last time, it won't happen again."
  • graeme_s-2
    graeme_s-2 Posts: 3,382
    It makes me laugh that most (if not all) of the people who come on here claiming that carbon fibre bikes will atomise if you look at them funny are presumably riding around on bikes with carbon forks. If you trust your carbon forks, then why not the rest of the bike? If your forks have a sudden failure then you're still going to look like you're attempting a slow-mo recreation of the crash in the OP's post.
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    My bikes have always been carbon fibre free.
    There is a small piece of what looks like flexible carbon fibre on the rear of the saddle and the soles of my SPD-SLs are carbon fibre, but thats it. No carbon seat post, forks, wheels etc

    On the video, did the carbon crack when he was hammering the top tube towards the seat post, before he moved down towards the head tube and tested the carbon frame to destruction?

    I don't think that carbon frames melt in the rain, but it does seem to suffer sudden failures from 'minor' impacts that other materials would withstand more frequently than I reasonably expect.

    Paging Dhope.
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • Stiff_Orange
    Stiff_Orange Posts: 218
    Yeah Carbon fibre is so week. That's why all the safety cells in F1 cars are made of them.

    I assume that the nahsayers won't be flying in a Boeing 787 or Airbus A350 then?
  • bails87
    bails87 Posts: 12,998
    EKE_38BPM wrote:
    I don't think that carbon frames melt in the rain, but it does seem to suffer sudden failures from 'minor' impacts that other materials would withstand more frequently than I reasonably expect.

    Does it?

    I've been a regular on the MTB forum for a few years, bikes that undeniably take more abuse than ones on the road. There are plenty of carbon fibre MTBs being ridden, and I haven't heard of any 'catastrophic' failures of CF. Failures? Yes. Things like chainstays starting to crack but no more than alu.

    There are also plenty of CF bars, seatposts, stems being used, and I can only think of one thread where a carbon seatpost had failed.
    MTB/CX

    "As I said last time, it won't happen again."
  • notsoblue
    notsoblue Posts: 5,756
    EKE_38BPM wrote:
    My bikes have always been carbon fibre free.

    ^^ This explains a lot. I've only been impressed since I switched to carbon and won't hesitate to get another one.
    FCN 4 PX SL Pro SRAM Red
    FCN 8 Scott Sportster '05
  • Paul E
    Paul E Posts: 2,052
    My new frame has carbon seat stays and will have a carbon seat post too, am I worried, not in the slightest,

    I have seen more metal frames fail from fatigue etc than carbon ones and more planes have fallen from the sky from metal fatiuge than from the carbon reinforced composite structures failing on the aircraft and most modern planes have huge parts in that material.
  • notsoblue
    notsoblue Posts: 5,756
    Also, it works for planes. This is a Boing 787 having its wings stress tested:

    00gci.jpg
    FCN 4 PX SL Pro SRAM Red
    FCN 8 Scott Sportster '05
  • DonDaddyD
    DonDaddyD Posts: 12,689
    I reckon you can hit that kind of speed going down Balham Hill.
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  • bails87
    bails87 Posts: 12,998
    DonDaddyD wrote:
    I reckon you can hit that kind of speed going down Balham Hill.

    I don't know, hitting that kind of speed on the flat is going to be tough.
    MTB/CX

    "As I said last time, it won't happen again."
  • kelsen
    kelsen Posts: 2,003
    DonDaddyD wrote:
    I reckon you can hit that kind of speed going down Balham Hill.

    For the love of god DDD! Will you stop haverin' on about Balham Hill!
  • NGale
    NGale Posts: 1,866
    my engineering science teacher randomly showed the class that video during a lecture on thermodyamics. Cue sounds of 'oooowwww' followed by laughter from the class.

    Also during the course of the year we have seen an elephant being electrocuted in a lecture on stress strain theory and the tacoma bridge collapse during a lecture on electrical theory.

    Yes the lecturer is a bit mad, but then he's an ex RAF navigator so quite understandable :lol:
    Officers don't run, it's undignified and panics the men
  • desweller
    desweller Posts: 5,175
    DonDaddyD wrote:
    I reckon you can hit that kind of speed going down Balham Hill.

    How do you know if you're going up it or down it?*

    *The terms 'up' and 'down' are used here in a purely hypothetical sense. It is, after all, well known that there is no elevation change to be found on the road in question.
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    On Strava.{/url}

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