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#81
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Training or Plain Riding?
On Dec 10, 5:13*pm, John Forrest Tomlinson
wrote: On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C wrote: Yeah JT I am, and you know the person well since they are NECSA, and Nebra. Their experience is that steel and aluminium give warning. or crack before snapping catastrophically. I haven't studied it, they have. You're saying something slightly different now - that it's about warning before catosthropic failure. But back to the original statement -- the idea that carbon forks have any extra tendency to fail more often than steel or aluminum is just baloney, despte whatever studies this person has claimed to have done. I don't get that. If a study is valid it should be taken seriously. I just don't know of any such study. I agree with you that carbon is a safe material if well constructed. Once after cutting a carbon steer tube I spent some time playing with the scrap piece and came away impressed with its strength. I've used a lot of carbon and never had a failure. Bret |
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#82
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Training or Plain Riding?
On Dec 10, 7:26*pm, Bret wrote:
On Dec 10, 5:13*pm, John Forrest Tomlinson wrote: On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C wrote: Yeah JT I am, and you know the person well since they are NECSA, and Nebra. Their experience is that steel and aluminium give warning. or crack before snapping catastrophically. I haven't studied it, they have. You're saying something slightly different now - that it's about warning before catosthropic failure. But back to the original statement -- the idea that carbon forks have any extra tendency to fail more often than steel or aluminum is just baloney, despte whatever studies this person has claimed to have done. I don't get that. If a study is valid it should be taken seriously. I just don't know of any such study. I agree with you that carbon is a safe material if well constructed. Once after cutting a carbon steer tube I spent some time playing with the scrap piece and came away impressed with its strength. I've used a lot of carbon and never had a failure. Bret Bret look at the problems/recalls with the early Look forks, etc...This falls in line with the make sure it's good before using it argument. No question carbon done right is a solid material, but how many errors happened to get to today's reliabilty? I could point out that blacktop is black and JT would call me an idiot and mock me, or antything I cite. Bill C |
#83
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Training or Plain Riding?
On Wed, 10 Dec 2008 16:25:56 -0800 (PST), Bill C
wrote: On Dec 10, 7:13=A0pm, John Forrest Tomlinson wrote: On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C wrote: Yeah JT I am, and you know the person well since they are NECSA, and Nebra. Their experience is that steel and aluminium give warning. or crack before snapping catastrophically. I haven't studied it, they have. You're saying something slightly different now - that it's about warning before catosthropic failure. But back to the original statement -- the idea that carbon forks have any extra tendency to fail more often than steel or aluminum is just baloney, despte whatever studies this person has claimed to have done. Hey since I haven't researched it your opinion is as good as theirs, except anecdotally they claim to have picked more kids up off the pavement with carbon forks than others. If you've been around racing or cyclilng, it's pretty obvious who is right on this one. But hey, if you want to relay nonsense and then sorta disavow it, go ahead. Just mock them and move on. |
#84
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Training or Plain Riding?
"Bill C" wrote in message
... look at the problems/recalls with the early Look forks, etc...This falls in line with the make sure it's good before using it argument. The real problem is that it is fairly easy to get errors in the layup and when you make progressively lighter and lighter frames and forks, errors become a great deal more dangerous. No question carbon done right is a solid material, but how many errors happened to get to today's reliabilty? And THAT'S the point. A bubble in the steel tube can cause a crack. Since there is so much extra strength in a steel tube it usually can fail to the point where you discover the failure without catastrophic failures. I could point out that blacktop is black and JT would call me an idiot and mock me, or antything I cite. I can't understand what happened to that guy who used to have all the really intelligent questions and/or answers. |
#85
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Training or Plain Riding?
On Wed, 10 Dec 2008 16:26:36 -0800 (PST), Bret
wrote: On Dec 10, 5:13*pm, John Forrest Tomlinson wrote: On Wed, 10 Dec 2008 15:44:47 -0800 (PST), Bill C wrote: Yeah JT I am, and you know the person well since they are NECSA, and Nebra. Their experience is that steel and aluminium give warning. or crack before snapping catastrophically. I haven't studied it, they have. You're saying something slightly different now - that it's about warning before catosthropic failure. But back to the original statement -- the idea that carbon forks have any extra tendency to fail more often than steel or aluminum is just baloney, despte whatever studies this person has claimed to have done. I don't get that. If a study is valid it should be taken seriously. I just don't know of any such study. It's because I know about this person and a "study" be this person is probably an experience one anecdote second hand and two personal experience with other factors involved. Plus influence from a great guy who builds nice bikes with steel forks. Not the tight personal observation I'm bringing to it (and you bring below) let alone a real study. I agree with you that carbon is a safe material if well constructed. Once after cutting a carbon steer tube I spent some time playing with the scrap piece and came away impressed with its strength. I've used a lot of carbon and never had a failure. |
#86
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Training or Plain Riding?
On Wed, 10 Dec 2008 16:33:06 -0800 (PST), Bill C
wrote: Bret look at the problems/recalls with the early Look forks, etc...This falls in line with the make sure it's good before using it argument. No question carbon done right is a solid material, but how many errors happened to get to today's reliabilty? So this person you're talking about is going to use the far past to justify equipment decisions forever? And considering how many cheap bikes come with carbon forks nowaday, limit the riders choices? Great. I know this person is old, but I guess she wasn't around back in the day when steel forks broke a lot, otherwise this person wouldn't be letting kids ride anything. I'm not dissing this person in general, but this decision is dopey. If this person wants to push the kids to not think about bikes too much, and is getting bikes with good steel forks, great. But wong info has to be called wrong info, not backed perpetuated. I could point out that blacktop is black and JT would call me an idiot and mock me, or antything I cite. No, I don't stalk you except about your poltiical nonsense. And in this case, a tech myth. But if you want to take it personal, go ahead. |
#87
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Training or Plain Riding?
"Bret" wrote in message
... On Dec 10, 4:01 pm, "Tom Kunich" cyclintom@yahoo. com wrote: By the way Bret, I haven't noticed that anyone has been talking about broken forks and frames either but according to several shops in my area there are a great deal more such failures than before. I don't doubt that carbon fails at a higher rate when crashed hard. There are two important failure points - yield strength and ultimate strength. In steel these points are pretty far from each other so you get BENDING before you get total collapse. You feel or otherwise notice this sort of failure and take actions before the failures are serious. In top of the line aluminum frames these points are much nearer one another and until recently what manufacturers of aluminum frames did was to significantly overbuild their frames so that it took a lot to reach the yield point. Lately they've been building much lighter aluminum frames are they're becoming dangerous since they can fail suddenly and completely. Carbon fiber in the sort of layups they use for extremely light frames and forks have very little difference between the yield strength and the ultimate strength and essentially what happens is that it fails suddenly and completely. Early Look frames and those from conservative manufacturers are significantly overbuilt to achieve reliability. But the racing frames that are super light are becoming more and more common among street racers and these bikes are dangerous. A weight difference of just 1/2 lb could mean the difference between sudden failure and long term reliability. |
#88
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Training or Plain Riding?
On Dec 10, 6:07*pm, "Tom Kunich" cyclintom@yahoo. com wrote:
"Bret" wrote in message I don't doubt that carbon fails at a higher rate when crashed hard. There are two important failure points - yield strength and ultimate strength. In steel these points are pretty far from each other so you get BENDING before you get total collapse. You feel or otherwise notice this sort of failure and take actions before the failures are serious. In top of the line aluminum frames these points are much nearer one another and until recently what manufacturers of aluminum frames did was to significantly overbuild their frames so that it took a lot to reach the yield point. Lately they've been building much lighter aluminum frames are they're becoming dangerous since they can fail suddenly and completely. Carbon fiber in the sort of layups they use for extremely light frames and forks have very little difference between the yield strength and the ultimate strength and essentially what happens is that it fails suddenly and completely. Engineer Man, This is a misunderstanding of the difference between yield failures and fatigue failures, and the relative danger of each in bicycle applications. You get bending without breaking in steel from a single high force incident, like a crash. You crash, you pick the bike up (or someone else does if you're not in one piece) and it's bent if it's steel, broke if it's aluminum. Who cares? You're still on the ground. Fatigue failures without high forces are where the danger is in bicycles. You don't notice that a part is cracked halfway through until it cracks the rest of the way and you fall down. It is true that many steel alloys have a fatigue limit and aluminum doesn't, but this is somewhat academic since steel parts that are not overbuilt can still fatigue and fail. Ultralight stuff will have a tendency to fatigue and fail whether it is steel, aluminum, titanium, carbon, or overly thin Spandex shorts material. There are some places where steel is desirable due to dimensional limitations (pedal and traditional BB spindles) but not because it's magically immune to failure. Back in the day, you could have bought a steel frame made out of superlight tubing (KL, Foco?) and it would be light, but it would eventually break under normal use. Most people wouldn't sell or buy such a frame then. If anything, aluminum and carbon allow the manufacturers to make superlight frames with a lower failure rate. But there is still a failure rate, because of Fatties like Justin the Bianchi man and your good self, buying 2.5 lb frames and expecting them to last as long as 4 lb frames. You can't buy speed. At least, you can't buy more than a little speed, and what you can buy is in aero wheels more than lightweight crap. So if you aren't willing to invest time and money in inspecting and replacing ultralight stuff, don't buy ultralight stuff. Ben RBR Personal Shopper |
#89
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Training or Plain Riding?
" wrote in message
... This is a misunderstanding of the difference between yield failures and fatigue failures, and the relative danger of each in bicycle applications. Maybe you could point out where I mentioned fatigue failures? You get bending without breaking in steel from a single high force incident, like a crash. You crash, you pick the bike up (or someone else does if you're not in one piece) and it's bent if it's steel, broke if it's aluminum. Who cares? You're still on the ground. Perhaps you ought to actually pay attention to what I was saying instead of what you wish I had said that you could criticize? Fatigue failures without high forces are where the danger is in bicycles. Perhaps you didn't follow the idea of construction errors? You don't notice that a part is cracked halfway through until it cracks the rest of the way and you fall down. Most steel frame failures of that sort leaves the bike able to be ridden home. Ultralight stuff will have a tendency to fatigue and fail whether it is steel, aluminum, titanium, carbon, or overly thin Spandex shorts material. There are some places where steel is desirable due to dimensional limitations (pedal and traditional BB spindles) but not because it's magically immune to failure. Now where did I say that steel didn't fail? Perhaps you ought to actually add to a conversation instead of trying to shoot someone down to such an extend that you will purposely change the meaning of the discussion? |
#90
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Training or Plain Riding?
In article
, Amit Ghosh wrote: On Dec 10, 6:16*am, John Forrest Tomlinson Yeah. One easy way for bike racing to stay more reasonable in pricing would be to require rims be made of metal and not more than 2cm deep or something. dumbasses howard and JT , i think the rules make it so that the sport is fair already. there's nothing wrong with people that want to spend $10,000 on a bike or discuss the merits of different spoke counts all day, but it's a hobby which has nothing to do with bike racing. it's just a distraction, but most racers don't realize until they've been racing for 5 yrs or so. The fastest new-to-the-sport rider I ever saw made his introductions by riding away from a Cat 4/5 field on one of the hilliest road circuits we do locally (Tom Furst, Westside Classic). He did this 3 or 4 years ago, on a steel six-speed Pinarello. He went on to other non-racing hobbies, but I didn't get an impression the bike was a major impediment. I'd go so far as to guess (bet?) that any rider good enough to turn pro would be able to make it to Cat 2 with relative ease on a bike no better than that one. If you want an off-the-rack example, I'd say that a Pro-potential rider could upgrade from Cat 5 to Cat 2 (at least in our local series) in one season, using an off-the-rack Sora-equipped bike. That is a bike that costs about $600-700 at full MSRP. -- Ryan Cousineau http://www.wiredcola.com/ "In other newsgroups, they killfile trolls." "In rec.bicycles.racing, we coach them." |
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