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  1. #101
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    Quote Originally Posted by I-Like-To-Bike View Post
    This analysis/comparison is fairly typical of some BF posters' method of determining that X activity is "statistically safer" than Y activity.
    I have linked to FARS/ACS data on this site multiple times. Then again it's probably difficult to notice this when one is constantly asking for data, evidence, and/or statistics while almost never contributing to the topic under discussion.


    A pictorial summary that should be clear even to concern trolls can be found here:

    Benchmarking - Alliance for Biking & Walking

    Enjoy.
    Last edited by spare_wheel; 08-07-14 at 12:34 PM.
    Road rash is a precious gift. Road rash is your friend. Bask in it, appreciate it, love it. Above all, learn from it. --Robert Hurst

  2. #102
    Been Around Awhile I-Like-To-Bike's Avatar
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    Quote Originally Posted by spare_wheel View Post
    If you had been paying attention you would have noticed that I have linked to FARS/ACS data here multiple times.

    A pictorial summary of this type of analysis can be found here:

    Benchmarking - Alliance for Biking & Walking

    Enjoy.
    Nowhere does anyone make a foolish comparison between cycling and walking in order to declare that one activity is statistically safer than the other.

  3. #103
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    Quote Originally Posted by I-Like-To-Bike View Post
    Nowhere does anyone make a foolish comparison between cycling and walking in order to declare that one activity is statistically safer than the other.
    cycling and walking have had about the same ACS mode share in portland (~6%) for years but pedestrian fatality rates are 3-∞ times higher every year. it does not take a test of the null hypothesis to see obvious significance. but since you are such an expert on statistics perhaps you could pick a regression analysis and FDR-adjustment and I will perform them with full documentation and R code.
    Road rash is a precious gift. Road rash is your friend. Bask in it, appreciate it, love it. Above all, learn from it. --Robert Hurst

  4. #104
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    Quote Originally Posted by spare_wheel View Post
    cycling and walking have had about the same ACS mode share in portland (~6%) for years but pedestrian fatality rates are 3-∞ times higher every year. it does not take a test of the null hypothesis to see obvious significance. but since you are such an expert on statistics perhaps you could pick a regression analysis and FDR-adjustment and I will perform them with full documentation and R code.
    The beauty of statistics is that you can make them prove or disprove just about anything you want.

    In this case, deaths are fairly easy to count, but how to quantify the base numbers (denominator), Regardless of how the mode share is counted, I suspect (just speculating) that there are more pedestrians out and about at any time than bicyclists. OTOH, most of them spend most of the time on the relatively safe sidewalks. So how and what do you count to get the denominator?

    BTW- I have no dog in this fight, nor in the anti-carbon nonsense that spawned it (indirectly). Just pointing out that debating these kinds of things mostly boils down to apples and oranges.
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  5. #105
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    Quote Originally Posted by 02Giant View Post
    The wishbones on F1 cars have been carbon fiber for close to 20 years.
    Shhhh. Don't tell them about the brakes.
    (Though one right front Brembo asploded at Hockenheimring recently. Notable mostly because brake failures are so rare now. Wonder what they used to be made out of?)

    Let alone the *gasp* helmets.


    Now back to your regularly scheduled descent into something that has absolutely nothing to do with the topic, in this case lights, mirrors, and walking....

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  6. #106
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    Quote Originally Posted by FBinNY View Post
    Regardless of how the mode share is counted, I suspect (just speculating) that there are more pedestrians out and about at any time than bicyclists. OTOH, most of them spend most of the time on the relatively safe sidewalks. So how and what do you count to get the denominator?
    Of course we can argue about whether a statistic should be measured or stratified by trip, distance, time, or type of trip. However, if measurements of risk are so fundamentally flawed then what exactly is the rationale for using safety gear X?
    Custom? Tradition? Fashion?
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  7. #107
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    Quote Originally Posted by spare_wheel View Post
    However, if measurements of risk are so fundamentally flawed then what exactly is the rationale for using safety gear X?
    It's called FUD. Some folks are expert on the F. Some are expert on the UD. Which are you? (I say, I say, I say, that's a rhetorical question son.)

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  8. #108
    Been Around Awhile I-Like-To-Bike's Avatar
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    Quote Originally Posted by spare_wheel View Post
    if measurements of risk are so fundamentally flawed then what exactly is the rationale for using safety gear X?
    Custom? Tradition? Fashion?
    Do you really believe that measurement/evaluation of safety/risk for pedestrians or bicycling is nothing more than providing "stats" of total fatalities and nothing more? "ACS mode share" means almost nothing as it provides only the vaguest correlation to total pedestrian or bicyclist exposure to hazard and zero relationship to all bicyclist or pedestrian exposure that occurs when not commuting. This juggling of almost random numbers supports nothing you are claiming about statistical safety.

  9. #109
    Senior Member rydabent's Avatar
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    Any comments on posts that says my CF bike fell over and was punctured by a sharp object?

  10. #110
    Senior Member goldfinch's Avatar
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    The article which is the topic of discussion is not evidence, it is anecdote. Now the anecdotes could lead to someone gathering data to quantify the risks presented by different types of bike frames. Is in fact carbon more prone to catastrophic failure than other materials?

    Anyone aware of any details regarding lawsuits for injuries based on carbon fiber catastrophic failure? That would be interesting to know. There must be some. I am sure a Lexis/Nexis search would turn up something. Anyone do such a search? It would be nice to see some expert testimony in the context of a suit. How about for other materials? Certainly we would have heard if there have been any class action suits. So, even if there are failures they are not so prevalent to have lead any lawyers to start a class action. I know that suits get settled, and there are often confidentiality agreements, but experts are not bound by those agreements. Anyone aware of any expert going around saying that carbon presents an unreasonable risk? Or is it a case where some manufacturers do a better job than others and there may be a particular manufacturing or design problem with a particular product?

    Anyone aware of any recalls of forks, seat tubes, or other carbon parts?

    Anyone aware of any data which shows that people are missing problems with their frames or forks (such as chips, nicks, cracks, performance problems etc.) that have lead to frame failure, whatever the material?

    If I wasn't retired and no longer have free access to Lexis or Westlaw, I would poke around. Hey lawyers, get on it!

    I think the bottom line is that we don't have enough facts, but carbon isn't like the Corvair, unsafe at any speed.

  11. #111
    Senior Member hotbike's Avatar
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    IMG_0004 by AviationMetalSmith, on Flickr

    The problem , if you analyze it, (and I have analyzed it), is that the manufacturers are building and selling "carbon copies" of the traditional CrMo Steel Bikes. Not too good an idea, The materials are completely different.

    IMHO, a Carbon Fiber Bicycle should be more like a Fiberglass Bicycle. Glass Fiber and Carbon Fiber are worked in a similar way. The overall Tubing Diameter should be larger than what would be used in a Steel Bicycle.

    Maybe the problem is a lack of Fiberglass Bicycles to base the design on? There are the Bowden Spacelander, of which only 522 examples were built, and the Fiberglass Ladies Bicycle (pictured above), which is very rare, I built one and Robert Egger built one, and I don't know of any Fiberglass Ladies Bicycles except those two.

    That's the answer , base the design on a Fiberglass Bicycle. You'll just have to learn to live with the Futuristic Styling, which is inherent in a good design.
    http://www.flickr.com/photos/11629987@N02/sets/72157639939606343/

  12. #112
    Been Around Awhile I-Like-To-Bike's Avatar
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    Quote Originally Posted by goldfinch View Post
    . Hey lawyers, get on it!

    I think the bottom line is that we don't have enough facts, but carbon isn't like the Corvair, unsafe at any speed.
    And the OP is not Ralph Nadar; doubtful that any competent lawyer is going to "get on it" or pay to much attention to the meandering rants posted on BF.

  13. #113
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    Quote Originally Posted by I-Like-To-Bike View Post
    This juggling of almost random numbers
    still waiting for you to pick a regression test...

    "ACS mode share" means almost nothing...nothing more than providing "stats" of total fatalities and nothing more...supports nothing you are claiming about statistical safety.
    logical nihilism.
    Road rash is a precious gift. Road rash is your friend. Bask in it, appreciate it, love it. Above all, learn from it. --Robert Hurst

  14. #114
    Senior Member rebel1916's Avatar
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    Quote Originally Posted by hotbike View Post
    The problem , if you analyze it, (and I have analyzed it), is that the manufacturers are building and selling "carbon copies" of the traditional CrMo Steel Bikes. Not too good an idea, The materials are completely different.

    IMHO, a Carbon Fiber Bicycle should be more like a Fiberglass Bicycle. Glass Fiber and Carbon Fiber are worked in a similar way. The overall Tubing Diameter should be larger than what would be used in a Steel Bicycle.

    Maybe the problem is a lack of Fiberglass Bicycles to base the design on? There are the Bowden Spacelander, of which only 522 examples were built, and the Fiberglass Ladies Bicycle (pictured above), which is very rare, I built one and Robert Egger built one, and I don't know of any Fiberglass Ladies Bicycles except those two.

    That's the answer , base the design on a Fiberglass Bicycle. You'll just have to learn to live with the Futuristic Styling, which is inherent in a good design.
    Um tube diameters ARE much larger for CF. What are you talking about?

  15. #115
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    Quote Originally Posted by hotbike View Post
    The problem , if you analyze it, (and I have analyzed it), is that the manufacturers are building and selling "carbon copies" of the traditional CrMo Steel Bikes. Not too good an idea, The materials are completely different.
    Spinelli_Corvid_Built_1.jpg

    A few (very, very few) manufacterers are but I can't justify buying one...
    Road rash is a precious gift. Road rash is your friend. Bask in it, appreciate it, love it. Above all, learn from it. --Robert Hurst

  16. #116
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    Given that this is starting to sound like the helmet thread, maybe the mods, need to start a permanent "carbon fiber" thread so folks can rant pro or con freely.
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  17. #117
    Senior Member Cyclosaurus's Avatar
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    Quote Originally Posted by hotbike View Post
    IMG_0004 by AviationMetalSmith, on Flickr

    The problem , if you analyze it, (and I have analyzed it), is that the manufacturers are building and selling "carbon copies" of the traditional CrMo Steel Bikes. Not too good an idea, The materials are completely different.

    IMHO, a Carbon Fiber Bicycle should be more like a Fiberglass Bicycle. Glass Fiber and Carbon Fiber are worked in a similar way. The overall Tubing Diameter should be larger than what would be used in a Steel Bicycle.

    Maybe the problem is a lack of Fiberglass Bicycles to base the design on? There are the Bowden Spacelander, of which only 522 examples were built, and the Fiberglass Ladies Bicycle (pictured above), which is very rare, I built one and Robert Egger built one, and I don't know of any Fiberglass Ladies Bicycles except those two.

    That's the answer , base the design on a Fiberglass Bicycle. You'll just have to learn to live with the Futuristic Styling, which is inherent in a good design.
    Yes...that is so futuristic...

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  18. #118
    Senior Member hotbike's Avatar
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    Quote Originally Posted by rebel1916 View Post
    Um tube diameters ARE much larger for CF. What are you talking about?
    Yes, that's right. The tube diameter needs to be larger for CFRP. That is the thing to look for when buying a Carbon Fiber frame.

    Also, bikes such as the Colnago C4 are Monocoques . The Carbon is continuous, the strands of Carbon in the top-tube are wound helically, and follow through the head-tube, until they are part of the down-tube. Monocoque is much better than those early frames, where the narrow carbon tubes were literally glued into aluminum Lugs.

    Anyway, a Monocoque frame can be formed around a foam core, using Epoxy resin.

    Photos I have seen suggest that the Fiber was too dry, not enough Epoxy resin. I believe some builders squeeze out too much resin, in an attempt to lighten their frames. You've got to leave enough resin in the Composite to 1) hold the fibers together, and 2) give the tube enough Wall Thickness.

    Wall Thickness is up there with Tube Diameter in determining the yield strength of the finished frame. With very thin wall tubing, the aforementioned Foam core can prevent the tube from being crushed from reasonable impacts.

    My Opinion is that you could make a *Composite* frame, using 90% Glass Fiber , and 10% Carbon Fiber, and "get the most bang for your buck" .
    Last edited by hotbike; 08-09-14 at 10:31 AM.
    http://www.flickr.com/photos/11629987@N02/sets/72157639939606343/

  19. #119
    Senior Member Homebrew01's Avatar
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    Just because a badly written article is in the NYT, does not make it true.
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  20. #120
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    Quote Originally Posted by Homebrew01 View Post
    Just because a badly written article is in the NYT, does not make it true.
    OMG-----Really? Say it isn't so!
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  21. #121
    Senior Member FlatSix911's Avatar
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    Quote Originally Posted by spare_wheel View Post
    I have linked to FARS/ACS data on this site multiple times. Then again it's probably difficult to notice this when one is constantly asking for data, evidence, and/or statistics while almost never contributing to the topic under discussion.
    A pictorial summary that should be clear even to concern trolls can be found here: Benchmarking - Alliance for Biking & Walking
    Enjoy.
    Interesting data ...





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  22. #122
    Senior Member Homebrew01's Avatar
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    Quote Originally Posted by rydabent View Post
    Any comments on posts that says my CF bike fell over and was punctured by a sharp object?
    Metal frames can be damaged in falls too.

    CF is often easier to repair than metal. Steel frame repair requires a torch that ruins the paint job. Aluminum frames cannot be rewelded in many cases, because the heat-treating would need to be redone (depends on the situation).
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  23. #123
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    Quote Originally Posted by Homebrew01 View Post
    Metal frames can be damaged in falls too.
    That's true, but the threshold for structural damage will be higher for metals than composites. Also scratches, chips, and dings that would be nothing more than cosmetic on metal can continue to degrade in composites if not addressed. Not really a big deal as long as one is aware of the materials needs.

    Composites aren't new, just the materials, Cool story about a 2000 mile voyage in a composite canoe, circa 1870s. Voyage of the Paper Canoe by Nathaniel H. Bishop - Free Ebook

  24. #124
    Senior Member elcruxio's Avatar
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    Quote Originally Posted by kickstart View Post
    That's true, but the threshold for structural damage will be higher for metals than composites. Also scratches, chips, and dings that would be nothing more than cosmetic on metal can continue to degrade in composites if not addressed. Not really a big deal as long as one is aware of the materials needs.

    Composites aren't new, just the materials, Cool story about a 2000 mile voyage in a composite canoe, circa 1870s. Voyage of the Paper Canoe by Nathaniel H. Bishop - Free Ebook
    well that's not exactly true. it pretty much comes down to the frame but if you take a carbon/alloy/steel freeride or AM frame and bash it against a concrete block with all your might it's quite likely that the carbon frame will handle it fine where the metal frames will be completely destroyed. There was a video of the subject. Carbon won with flying colours.

  25. #125
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    Quote Originally Posted by elcruxio View Post
    well that's not exactly true. it pretty much comes down to the frame but if you take a carbon/alloy/steel freeride or AM frame and bash it against a concrete block with all your might it's quite likely that the carbon frame will handle it fine where the metal frames will be completely destroyed. There was a video of the subject. Carbon won with flying colours.
    Both are true, a composite can rebound back from a hit that would fatally bend or dent a metal structure, but it will almost certainly sustain irreparable damage that will continue to degrade the integrity structure with the same ultimate result.

    I really don't see how one can legitimately argue the absolute superiority of one over the other as they both have strengths and weaknesses, it really comes down to how they are formed and used......and personal preferences.

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