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  1. #1
    Senior Member Seattle Forrest's Avatar
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    You can stand on carbon fiber handlebars

    Not that you really want to ... it's no more fun than standing on the ground. Much better to ride a bike with handlebars, than use them as a stool.

    But the bars weigh 180 grams, and I weigh about 210 lbs. I was able to stand on them without hearing them crack. No visible damage from the experience.

    I think carbon fiber is strong enough for Clydes and Athenas to ride as a frame material.

    Don't believe everything you think.

  2. #2
    Banned. Mr. Beanz's Avatar
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    One of the pro teams (I believe RadioShack) went back to alum bars realizing there was less of chance of injury with a minimal weight penalty.

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    I will stick with aluminum bars because Carbon cost too darn much, and don't allow for cheap bar ends to be used (flat bars)...
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    You gonna eat that? Doohickie's Avatar
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    Of course they can withstand 210 lb. How hard does a cyclist pull on bars when climbing? Add a bit of safety factor, 210 lb. easy.
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    Originally Posted by bragi "However, it's never a good idea to overgeneralize."

  5. #5
    Senior Member Seattle Forrest's Avatar
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    When I'm climbing, I leverage the handlebars, but most of my weight is on the pedals.

    Quote Originally Posted by nymtber View Post
    I will stick with aluminum bars because Carbon cost too darn much, and don't allow for cheap bar ends to be used (flat bars)...
    Use whatever you like. But don't stick with aluminum because your Hulk-like strength might snap carbon ones like a twig. You won't. I suspect the same thing goes for frames.
    Don't believe everything you think.

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    I love these threads about whether "carbon" is appropriate for clydes or not. Not all carbon components are equal. Any more so than all aluminum components. One of our local lbs had a collection of all the off cuts from shortening carbon seatpost and mtb bars. The variation in material, layup, resin to fiber ratio and general thickness is staggering.

    Components can be engineering and manufactured for a desing specification in carbon as easily or maybe even more so than any other material. That doesn't mean to imply that all carbon components are or are not suitably for clydes. Some are, some aren't. Choose wisely.

    I still don't like the fashion in which it fails. But, having ridden carbon forks for years (at 250-295lbs) without incident, my next frame will hopefully be just that.
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  8. #8
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    Quote Originally Posted by Seattle Forrest View Post
    ...Much better to ride a bike with handlebars, than use them as a stool...

    SF, what brand are those bars (can't quite read it in image)?

    And, saying in a nice way, what prompted you to stand on them?

    Curious in the manner in which you stood on them. Did you stand on the drops as they were elevated or with upper bar area simply flat to floor?
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    Senior Member himespau's Avatar
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    I'm cheap. If I had the cash I'd go for carbon (and a new bike), but I ride a heavy steel bike so carbon bars would look silly.


    Yeah, why did you stand on them? Just an accident or did you really want to know?
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    Senior Member Waxbytes's Avatar
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    "...I was able to stand on them without hearing them crack. "



    How good is your hearing?
    Last edited by Waxbytes; 02-21-12 at 02:25 PM.
    Uhmm...

  11. #11
    Senior Member Seattle Forrest's Avatar
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    Quote Originally Posted by bike_boy View Post
    SF, what brand are those bars (can't quite read it in image)?

    And, saying in a nice way, what prompted you to stand on them?

    Curious in the manner in which you stood on them. Did you stand on the drops as they were elevated or with upper bar area simply flat to floor?
    They're Kestral ... I'm not sure which specific ones, but they're in SLs. And they're supposed to not be aero-bar compatible.

    Mostly it was curiosity. The bars themselves were already toast. Mine are 26 mm, and I had put them in a 31.8 mm stem, using a shim. Then I hand-tightened them, but not enough. While I was out riding, I hit a bump, and they slid in the shim; the edges cut into the clamping area of the bars. I've been wondering what to do with them, and I wanted to know how strong they are.

    I stood on the drops themselves. Which means it was the arch structure as much as any magic in the carbon, that held my weight up. I posted about it because (1) I thought it was mildly interesting, and (2) I keep hearing about how entire frames made from the material are no good. My thinking is that if a kaput handlebar tipping the scales at 180 g can hold up my 95 kg mass, then a frame that was designed to hold a person's entire weight can probably do its job, too.
    Don't believe everything you think.

  12. #12
    Senior Member squirtdad's Avatar
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    based on everything I have read....it is not that carbon fiber is no good or not stong, it is that it has a very unforgiving failure mode. When it fails it is all at once. Also it is more sensitive in terms of things like deep scratches. A deep scratch (through the gel coat...even hitting some fiber) can become a failure point very quickly. So the general recommendation is to be nice to the carbon, inspect carefully and regularly and make the frame art if you see any cracks at all.
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    Quote Originally Posted by squirtdad View Post
    based on everything I have read....it is not that carbon fiber is no good or not stong, it is that it has a very unforgiving failure mode. When it fails it is all at once.
    Just like aluminum? Or modern thin-walled steel tubing?

    Also it is more sensitive in terms of things like deep scratches. A deep scratch (through the gel coat...even hitting some fiber) can become a failure point very quickly.
    I'm not sure if this was ever true, but it certainly isn't true with modern carbon fiber construction methods. At least for bike frames; I don't know about handlebars or other parts. A modern carbon lay-up uses multiple layers with different compositions and orientations. Scratching the clearcoat or cutting through a small number of fibers on the outermost layer isn't going to compromise the structure. If you somehow manage to cut through multiple layers, then you should probably start worrying...

  14. #14
    Senior Member funrover's Avatar
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    Quote Originally Posted by lenny866 View Post
    WOW!! That website shows the brutal side of it all! Thanks for the link!

  15. #15
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    There are busted steel, aluminum and titanium and in reality if you know the right people carbon can be easy to fix. As for bars there are many pro teams who use aluminum bars, Cadel Evans likes and old set of low drop track bars and you can be sure they aren't carbon! I myself have aluminum but it's a money slash why carbon thing.
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    Not as worried about the standing weight. That's a static load.

    Vibration from the road, with a little bit of weight on, can destroy handlebars. I know a local racer guy who replaced his handlebars every 2-3 years just from stress loading. Aluminum especially gets brittle over repeated stressing. What does carbon do? Dunno.

  17. #17
    Senior Member skilsaw's Avatar
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    I saw a triathlete break a seatpost on a borrowed bike. The post sheared off cleanly where the bike owner clamped it. One anecdote doesn't constitute science, but it motivates me to stay away from carbon.
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  18. #18
    Senior Member Seattle Forrest's Avatar
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    Quote Originally Posted by squirtdad View Post
    based on everything I have read....it is not that carbon fiber is no good or not stong, it is that it has a very unforgiving failure mode. When it fails it is all at once. Also it is more sensitive in terms of things like deep scratches. A deep scratch (through the gel coat...even hitting some fiber) can become a failure point very quickly. So the general recommendation is to be nice to the carbon, inspect carefully and regularly and make the frame art if you see any cracks at all.
    Carbon fiber seems to be more vulnerable to certain types of damage, mainly impacts. How much so, none of us probably know exactly. But it's something people who own CF bikes might be concerned with. And CF is more expensive than alu for bike frames. Whether it's worth the money, or whether a person is willing to take the care not to crash or drop their bike, is another question.

    Every month or so on the C&A forum, somebody starts a thread about how they're buying a bike to get in shape, and they'd like a carbon one, but they're afraid their weight will crush it. That's what I'm addressing with this thread. Here's a post (the OP) from another thread on the front page of C&A:

    Quote Originally Posted by A fellow Clyde View Post
    I am 6'7 and around 290lbs. I'm looking at some new bikes and carbon is all the rage it seems, but i'm still worried about the issue of me being too heavy for a carbon frame. I've seen several articles on the net that claim carbon fiber tech has drastically improved in the last 10-15 years, but still, bikes are designed for skinny little European sized dudes, not big bears like me. So what do you guys think? Is carbon fiber ok for a guy my size?
    I don't know if this guy will use a torque wrench when he works on his bike, but I'm confident that a carbon frame will support his weight. And the same for anybody else in here. We should all worry less and ride more.
    Don't believe everything you think.

  19. #19
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    Quote Originally Posted by sstorkel View Post
    Just like aluminum? Or modern thin-walled steel tubing?



    I'm not sure if this was ever true, but it certainly isn't true with modern carbon fiber construction methods. At least for bike frames; I don't know about handlebars or other parts. A modern carbon lay-up uses multiple layers with different compositions and orientations. Scratching the clearcoat or cutting through a small number of fibers on the outermost layer isn't going to compromise the structure. If you somehow manage to cut through multiple layers, then you should probably start worrying...
    I could be wrong, but, with regard to Aluminum, it seems the most common failure mode is work harding that leads to a crack before catastrophic failure occurs. While there are certainly other failures, it seems the majority are either near weld beads or in any of frequent high flex (drive side chainstay just aft of BB). These "usually" provide a crack, flex, creak, before letting go completely. I realize there will be plenty of stories of JRA when something let go. But, generaly speaking, the majority of aluminum failures provide some warning signs if you know how to recognize them.

    With regard to carbon. I'd caution not to generalize all "modern" designs together. There are a lot of differing techniques in use and degrees of engineering. Everything from lugged carbon tubes, to glued together modular carbon sub frames. And, although some manufacturers refer to their frames as monocoque. I'm not aware of any that truly are. Layup schedules can and do vary greatly. The issue with carbon failure from scratches and chips is not the total number of threads that have been interrupted, but, that a stress riser may have been created. Image machining an inside radius from a block of aluminum. The longer the length of the radius on that inside corner, the less likely it is to develop a crack radiating outward. With the interruption of just a couple carbon threads the "crack" so to speak is already started and then propigates (sometimes very quickly) through the remaining material. This is enough of a concern that some manufactures prescribe the repair of even superficial gelcoat damage in order to mantain the integrity of some components.

    It's not that carbon can't be immensely strong. Just that we need to be careful about selecting appropriate components. There is a reason why manufacturers have starting prescribing weight limits to carbon components.
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    Quote Originally Posted by bigfred View Post
    But, generaly speaking, the majority of aluminum failures provide some warning signs if you know how to recognize them.
    Sounds like aluminum is very similar to carbon fiber in this regard!

    With the interruption of just a couple carbon threads the "crack" so to speak is already started and then propigates (sometimes very quickly) through the remaining material.
    No, it doesn't. At worst, it might propagate through a single layer of the carbon lay-up. Even that possibility seems remote. The likelihood that a scratch leads to catastrophic failure of the entire frame is minuscule. If carbon frames failed as often as you seem to be suggesting, nobody would be riding them and their manufacturers would have been sued into oblivion.

    This is enough of a concern that some manufactures prescribe the repair of even superficial gelcoat damage in order to mantain the integrity of some components.
    Name one?

    There is a reason why manufacturers have starting prescribing weight limits to carbon components.
    Right: it's because their lawyers have nothing better to do.

  21. #21
    Senior Member socalrider's Avatar
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    seen more than my fair share of broken carbon handlebars but never seen an alloy bar snap.. I'll stick with my Cinelli Graphis which only weigh 2 ounces more than carbon bars.

  22. #22
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    Quote Originally Posted by socalrider View Post
    seen more than my fair share of broken carbon handlebars but never seen an alloy bar snap.. I'll stick with my Cinelli Graphis which only weigh 2 ounces more than carbon bars.
    The only failure I ever had was on an aluminium handlebar. Snapped off at the barend as I was climbing a hill.
    It failed instantly and I instantly hit the ground. They all break.

  23. #23
    Senior Member Seattle Forrest's Avatar
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    The irony: a thread that tried to kill some of the irrational paranoia about carbon fiber is descending into irrational paranoia.

    He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you.
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  24. #24
    Gears? CliftonGK1's Avatar
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    My issue with carbon bars isn't strength. They're plenty strong for any just short of being a beastly world champion track sprinter.
    My issue is with the flexibility; it's what makes them great for things like Paris-Roubaix and other cobblestone or rough-road races. For singlespeeding around on all the hills that I do, I don't want power lost to flexing the bars when I pull on them for leverage. I'm not taking the time to look it up again, but one of the big bike mags did a handlebar flexibility comparison within the past year and for minimal weight differences, aluminum bars were far stiffer.

    There is a high probability that I will still use an aluminum bar when I build my carbon distance bike.
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  25. #25
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    Quote Originally Posted by CliftonGK1 View Post
    My issue is with the flexibility; it's what makes them great for things like Paris-Roubaix and other cobblestone or rough-road races. For singlespeeding around on all the hills that I do, I don't want power lost to flexing the bars when I pull on them for leverage. I'm not taking the time to look it up again, but one of the big bike mags did a handlebar flexibility comparison within the past year and for minimal weight differences, aluminum bars were far stiffer.
    You can read all the magazine articles you want, but sometimes it's useful to have real-world, hands-on experience with a product. I own both carbon and aluminum versions of 3T's Ergosum handlebar. Even during a 1000w sprint, I can't feel the carbon bars flexing!

    Which isn't to say I'd buy them again: they look super-cool, but there's not enough difference from aluminum to justify the MSRP. Luckily, I got the carbon bar on sale and only paid a $10 premium over the alloy version ($80 vs. $70).

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