carbon handlebars

Discussion in 'Cycling Equipment' started by sma, Dec 21, 2006.

  1. sma

    sma New Member

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    in calculating my future bike build, i've noticed that i can either spend a little extra money on carbon fiber handlebars vs. aluminum, or take that extra money and put it towards my wheels.

    so, do carbon fiber handlebars offer any sort of vibration dampening over aluminum? (i.e. is it worth the extra money?)
     
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  2. sogood

    sogood New Member

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    Take the second option. A good set of wheel is just wonderful. A carbon bar is only good for the bling in most cases.
     
  3. pixelmill

    pixelmill New Member

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    Carbon bars are quiet on the road - they do dampen the feel of the road - & they shouldn't cost too much [I paid $150 US for mine] - budget well and look on EBay for the bars & get both! :)
     
  4. JTE83

    JTE83 Member

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    I have 6 road bikes some CF some AL and I don't notice much of a difference in the ride. Maybe I'm a dead head in sensing it...
     
  5. sogood

    sogood New Member

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    "Cheap CF bars" are just CF wrap over alloy bar with extra $$$ for the CF gift wrapping, make bugger all difference. Real full CF bars are even more expensive with questionable benefits in feel and weight. Bottomline, negative cost benefit.
     
  6. alienator

    alienator Well-Known Member

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    So you think.

    If you've healed injuries susceptible to low amplitude, high frequency vibrations, CF bars can do the trick. I know because I have wrists that have been broken multiple times, and those low amp, high freq vibes took their toll on long rides. Slowly I changed things to find something that worked....different tires and pressures, different fork, different tape, different gloves, and finally different bars. The bars made a subtle difference, but it was an essential difference to me, quantifiable by the reduction in pain after long rides or being able to ride farther without issues. Whether others are sensitive to the vibration spectra that I am is unknown.

    As far as weight goes, properly designed CF bars can be lighter, but it takes proper design. Not all bars are done properly.
     
  7. sogood

    sogood New Member

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    Right Alienator. The qualifer on the full CF bar is proper design and there's not too many of those. And for those that are, they are pretty dear in the scheme of things. As for cost benefit, if it takes someone who had as many unfortunate wrist injuries as you've had to appreciate the difference and need, I'll have to say that the cost benefit is definitely not there for the great majority of riders. The cost benefit ratio of a bar that's 2-5x pricier than a good alloy bar may improve with greater rider mileage and physical debilities.
     
  8. alienator

    alienator Well-Known Member

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    I'd love to hear exactly what qualifies as worthy in a "cost benefit" analysis. I bet that can't be done. No, whether there is a cost benefit or not is entirely up to the individual. If all a person wants is the CF look and is willing to pay, then the cost benefit is there for them. If there is no bar whose shape and dimensions works for someone except for a CF bar (and this might be the case more than you think), then the cost benefit might work for them.

    CF bars are no more or less worthy than any other bars, no matter what people want to say. Whether they pass some cost benefit criterion or criteria is up to the individual, certainly NOT the massive numbers of cycling cognoscenti.

    To the OP: get what works for you, what fits you. Whether it's CF, aluminum, or a hybrid of CF and aluminum, it'll work best.
     
  9. sogood

    sogood New Member

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    You are in the commercial engineering field and I am totally surprised that you don't know what qualifies as worthy in a cost-benefit analysis <http://en.wikipedia.org/wiki/Cost-benefit_analysis>. And in this case, it's the performance gain/benefit vs cost. As for the benefit perceived by your wrist that has suffered from multiple fractures, I would say that it is a sensitive joint that has a n=1 +ve benefit. And per your routine argument, this could very well be a placebo effect. Given the lack of supportive and consistent report of benefits, I would say that from a scientific point of view, the benefit could not be concluded, or it's at a very low level that won't make a difference to most rider. Add to that, the price premium of CF, it's not exactly a smart move. High frequency damping? What frequency? Gel tape/gloves would significantly dampen them out to no less degree than a CF bar.
     
  10. alienator

    alienator Well-Known Member

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    First, who in the hell said I am in commercial engineering? Not me. That's for damned sure. I am a scientist, first and foremost. I have an BS in Physics, along with 3/4 of the work done for a BS in Mech E, and ongoing work on a PhD in Optics. Commercial engineering? You're kidding, right? That's not my bag. Not my bag at all. Almost all of my work has been in the novel application of science to unique needs, be those needs for the space program, special defense projects, astronomy, and etc. Man, the assumptions that people make are stupifying.

    Second, you need to read your clever cut and paste a little better. You'll note that it says, straight away, that cost benefit analysis is a calculation of initial and ongoing expenses vs. expected returns. There isn't squat in there that says anything about what form expected returns have to take. They can be minimum signal output from a sensor; they can be minimum necessary quality in an optical wavefront; they can be expected monetary returns on the investment; AND they can be totally intangible qualities. As such, there is no freaking way to categorically define cost vs. benefit analysis for bicycle customers in general. Nada. Zip. Cost benefit for a given customer might have beauty as the only benefit. For another customer, the only benefit might be in how much of a status symbol the part is. Some other cyclist may value low weight. Another may value color. Still yet another might only value how well something fits.

    And the beauty of any of the myriad of expected returns that a bicycle component customer might value can be things that only serve some psychological desire or need. They may have no real tangible, measurable benefit. Therefore, if something only provides a placebo benefit and that placebo benefit satisfies a particular expected return and the customer is ok with that, then everything is hunky-dory. It's well known that somethings really have no benefit other than a placebo benefit, but if you open your eyes, you will see that for the human species, the placebo benefit can be HUGE and have a very real effect on human performance, mood, and etc.

    You're right any benefit can be a placebo benefit. I worked for the better part of 6 months to make sure, as best I could, that I kept placebo benefits out of the picture and instead measured benefits according to whether or not a ride over a given routed required pain killers and ice afterwards. That is why I changed one thing at a time and evaluated said changes over a pretty long period of time.

    As for whether my benefit could be sensed by another rider? Who gives a damn? I'm the one who rides the bike, not some other guy or gal. And that is true for damn near everyone and their bikes. Do you buy things according to how they make others feel?

    And then you throw out this beauty:
    Uhm, remember that expected returns thing? Who the hell do you think you are to evaluate that for someone else?
    I've been to a lot of design meetings, critical design reviews, and etc., and I can say, without a doubt, that I've seen people, government agencies, and other entities pay gobs of money for expected returns that no one else thought were important. Guess what, cupcake, what I thought wasn't important: what the customer wanted and valued WAS the important thing.
     
  11. Retro Grouch

    Retro Grouch New Member

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    Ah, the perfect qualification for this board.
     
  12. sogood

    sogood New Member

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    Hehe... I knew that reply would get you really fired up. The causal-response relationship has been confirmed and what a beauty! :D

    As for the placebo effect, by all scientific methodology, the only fair way to eliminate that is through a double blinded trial. The fact that you knew what the changes were, along with the n=1 (you) sample size, irrespective how slowly you made the changes and what detailed observations you've made of yourself, the risk of placebo was still there. And as shown on many forum and Usenet discussions, even when not double blinded, there's hardly an overwhelming evidence of benefit of CF bars, 50:50 at best. And as you would well agree, that's hardly the odds to confirm a benefit.

    But I can agree with you that CF may provide real benefit in situations in very limited cases like your. For the vast majority of riders in the absence of pathology in the anatonomical and physiological sense, the price of a CF is mostly contributing to the bling factor rather than real ride benefit.

    BTW, I assume your perceived benefits with CF bars weren't tested on bikes with rigid steel forks, right?
     
  13. rayhuang

    rayhuang New Member

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    I thought or think one of the best reasons to go with a Carbon bar is the anatomical shape on the tops anf by the brake hoods that would be harder or impossible to shape in aluminum and add weight, where as you can get these shapes in CF for little to no weight penalty.
     
  14. alienator

    alienator Well-Known Member

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    Why thank you. It's good to know that the physics induced headaches along with the graduate school psychosis and paranoia is serving some greater purpose.

    I did forget to address this little tidbit ......

    Well, let's see Mr. Wizard. To get a rough estimate on the fundamental frequency generated by the road surface we can measure how many stones there are in some length of tarmac (to get a quasi decent number fairly quickly we could count stones along the edge of a ruler) and calculate the stones' spatial frequency, i.e. stones per inch, say. To make it more like a frequency we'll just say x/in, where x is the number of stones per inch, and we'll make a first order estimate that the frequency of vibrations will be some integer multiple of the stones spatial frequency (this'll be pretty close). Now calculate an average speed. For me we'll say the average speed is (depending on the ride: group rides, pacelines, ride to the corner store, the trudge home with bookbag full of books, and etc.) somewhere between 16 and 22mph. Let's pick the average and call it 19 mph. Convert that to inches/second, and we get 334.4 in/sec. Do this multiplication: veloctiy x spatial frequency to get a value for the upper limit on the fundamental frequency of vibration. If the spatial frequency is 3 stones/in=3/in, that gives a fundamental of 1003.2/sec or 1003.2 Hz. That's prolly high since the tires will kill some portion of the high freq vibes, but it puts us in the ballpark and gives a rough estimate of what the highest frequencies encountered might be. That also does not take into account whether or not a given frame can support modes of that frequency.

    As for the gloves and gel tape bit: read what I said earlier. I did try gloves--many kinds--and tape--also many kinds.
     
  15. sogood

    sogood New Member

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    Firstly, I would not dare to compete with you on the "Wizard" title on this board. :p

    As for the damping effect of gel, you'll have to agree with me that those gooey gels are some of the least desirable material for the efficient transmission of high frequency vibrations.

    As for your testing, not that I don't recognize your well intentioned scientific methodology, but the limit remains in that it was a perception of n=1, changes were separated temporally, non-blinded, you just can't get away from the possibility of placebo and all the criticisms of a non-double-blinded trial. Double blindedness may not be important in engineering testing, but for scientific testing involving human subjects (you are human, right? ;) ), it's the only gold standard for proof.
     
  16. alienator

    alienator Well-Known Member

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    There is no way for a single person to reliably do a double blind test on themselves, especially with a large enough, i.e. statistically significant sample size. I did as much as I possibly could, without resorting to paying volunteers with similar medical, specifically orthopedic, histories.

    50:50 at best? I doubt it. The thing that will tend kill high freq vibes in CF is all the interfaces between resin and fiber, as well as the interfaces between layers and layers of differing orientations. You can look at that and make a pretty good guess that such a medium would by unlikely to support high frequency and/or low amplitude vibes. One aspect of high freq vibes is poor penetration compared to vibes of relatively long frequency.

    That's a large assumption to make. CF bars are not just bought for the reasons you mentioned. Again a given set of CF bars may have the only geometry that works for someone. Someone else may be a gear head and appreciate the handywork and technology involved. Yet another person might get 'em because they match his or her bike the best. For someone else, CF bars might be the only bars that satisfy his weight requirements for a given geometry.

    Bling? I don't know what the hell that is. I suspect it's a word that folks throw around when they wanna appear hip and cool and stuff. It's a convenient and lazy way to pigeon hole people that someone is too lazy to evaluate with a bit more thought.

    Why? Is it time for a "steel is real" quote? Nope, they weren't tested with the steel forks. The steel forks were gone when it became apparent that CF forks provided more comfort than the steel forks. Again, this was decided after a period of testing.
     
  17. sogood

    sogood New Member

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    As I said earlier, I acknowledge the fact that you tried to be scientific with the subject n=1 and non-blinded limitations. Under that, placebo remained a possibility. And as suggested by rayhuang, who knows if there was a subtle difference in the geometry or some other engineering/design factor of the CF bar you used that contributed to your comfort and perception?

    The reason why I brought up the steel vs CF fork issue was that the benefit of vibration damping is so much more efficiently achieved at that location with CF. Whereas a CF bar may have a significantly greater benefit when paired with a steel fork. That's one scenario where a choice in CF stem/bar may have better cost-benefit ratio.

    You don't know what "bling" is? Ever heard of the term "weight weenie" in your cycling career? :eek:
     
  18. Bro Deal

    Bro Deal New Member

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    +1
    Solid point.
     
  19. alienator

    alienator Well-Known Member

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    You're right, but I've yet to find a comfortable pair. I have some Spenco Ironmans that just don't do that well. My thinish Specialized BG Pro gloves have a wee bit of gel, but certainly not as much as the Spencos. The BG Pros are the best I've ever worn.

    Well, I don't have to rule out placebo effect for myself: if the placebo effect does the job, so be it. I am very skeptical that the placebo effect would persist for so long and for such long rides. I don't know that the placebo effect could reduce visible inflammation like I have noticed. And it's not as if I have an emotional investment in the bars: very little of them of shows, and what does show just looks like bars painted flat black.
     
  20. CAMPYBOB

    CAMPYBOB Well-Known Member

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    I wish you hadn't said that.

    I feel another 300-word 'he blinded me with science' lecture coming on.
     
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