NPR on carbon fiber bikes
08-19-18, 11:12 PM
#26
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I'm guessing @Slightspeed forgot to use the sarcasm font?
08-19-18, 11:16 PM
#27
Cycling addiction
Not full carbon on my LeMond Reno, but carbon fork and seatpost. I’m worried that it may fail on me. My other carbon frame bike is the centurion David Scott Carbon and I don’t ride it that much
08-20-18, 05:15 AM
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Now I've got a problem. I'm pro carbon and definitely anti this administration. What's a person to do? I guess I'll just listen to the anti admin, and skip the anti carbon stuff. Bottom line, it all comes down to choices. I love my carbon, I love my vintage steel, current administration, not so much.��
I'm not pro or for, I just like to listen to news without the whining or cheerleading.
Which means, these days, the farm report is about all I can find....
Then again, the carbon warnings warm my heart.
08-20-18, 08:20 AM
#30
Steel80's
From a C&V perspective, I have to wonder if the rise of carbon means a slow death for riding older bikes. That is, as more new bikes are made of it, the C&V bikes of the future will end up in pieces in a dumpster.
I personally wouldn't trust a used carbon frame unless it was in immaculate condition. I admit I enjoy having carbon forks and seatposts on a couple of bikes, but I know they haven't been beaten on or installed improperly.
I personally wouldn't trust a used carbon frame unless it was in immaculate condition. I admit I enjoy having carbon forks and seatposts on a couple of bikes, but I know they haven't been beaten on or installed improperly.
08-20-18, 08:47 AM
#31
Full Member
And then after some 50 years someone will "invent" the lugged steel frame and everybody will want to have one.
08-20-18, 01:32 PM
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Carbon fiber had long been touted for it's higher damping coefficient than metals, which implies that the ride is better. But the damping coefficient of carbon fiber or CFRP is actually extremely low as compared to any kind of decent suspension unit, so far more of any flex/vibration energy still gets absorbed by the tires and rider at either end of the carbon frameset structure than gets absorbed into the frameset.
And carbon's damping coefficient only goes down as the performance rating (strength and stiffness-to-mass) of the carbon increases.
In the end, I believe carbon forks and frames are stiffer these days than steel framesets of the past, so most of any significant flex and damping has to come from larger, softer tires, which makes claims as to carbon's supposed increased damping sort of specious. Certainly carbon can be made with layers of different materials and bias angles, but not so much the case when lowest weight is sought.
So if wider tires can be aerodynamically streamlined with the right sort of lightweight rims and frameset, and at low weight and modest cost, perhaps the modern bicycle can be a better mousetrap. Some would say that it already is, but realistically the price of the good, light ones tends to be very high.
And carbon's damping coefficient only goes down as the performance rating (strength and stiffness-to-mass) of the carbon increases.
In the end, I believe carbon forks and frames are stiffer these days than steel framesets of the past, so most of any significant flex and damping has to come from larger, softer tires, which makes claims as to carbon's supposed increased damping sort of specious. Certainly carbon can be made with layers of different materials and bias angles, but not so much the case when lowest weight is sought.
So if wider tires can be aerodynamically streamlined with the right sort of lightweight rims and frameset, and at low weight and modest cost, perhaps the modern bicycle can be a better mousetrap. Some would say that it already is, but realistically the price of the good, light ones tends to be very high.
08-20-18, 02:26 PM
#34
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Carbon frames have been king for a while now. It is hard for me to believe that the bike companies do not keep statistics on failure rates. It would be incompetent not to. Let's assume for argument that they do keep statistics. If carbon failure rates were lower than steel, don't you think the bike manufacturers would be crowing about it? The fact that it's never mentioned leads me to believe that the failure rates are higher than they were before - when steel was king.
Completely subjective observation. Steel frame failures used to be exceedingly rare. By contrast, carbon composite failures seem to happen fairly often.
BTW I'm not anti carbon. First carbon bike I rode was IIRC one of those Giant Cadex bikes circa 1989(?) or so. It was immediately obvious even then that it was better. Really stiff and responsive. Yeah, I'm one of those people that think stiffness is better, or at least faster. Carbon fiber's big party trick is that it is about the stiffest material by weight that there is. If you don't like stiff, not a good choice. Damping or any other properties are secondary if not tertiary IMO. I don't have one because modern steel OS tubesets are plenty stiff enough, and I don't have to worry at all about hitting the frame with rocks and sticks, which happens fairly often where I often ride. Also, and this is the big one, I'm not at that sort of competitive weight where the 1 or 2 pounds I'd save with carbon is significant. I'm pretty sure that's the case for nearly all recreational riders.
Completely subjective observation. Steel frame failures used to be exceedingly rare. By contrast, carbon composite failures seem to happen fairly often.
BTW I'm not anti carbon. First carbon bike I rode was IIRC one of those Giant Cadex bikes circa 1989(?) or so. It was immediately obvious even then that it was better. Really stiff and responsive. Yeah, I'm one of those people that think stiffness is better, or at least faster. Carbon fiber's big party trick is that it is about the stiffest material by weight that there is. If you don't like stiff, not a good choice. Damping or any other properties are secondary if not tertiary IMO. I don't have one because modern steel OS tubesets are plenty stiff enough, and I don't have to worry at all about hitting the frame with rocks and sticks, which happens fairly often where I often ride. Also, and this is the big one, I'm not at that sort of competitive weight where the 1 or 2 pounds I'd save with carbon is significant. I'm pretty sure that's the case for nearly all recreational riders.
08-20-18, 03:11 PM
#35
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I know this thread is partially about NPR but let’s keep political comments out. Thanks
08-21-18, 12:00 AM
#36
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Carbon fiber had long been touted for it's higher damping coefficient than metals, which implies that the ride is better. But the damping coefficient of carbon fiber or CFRP is actually extremely low as compared to any kind of decent suspension unit, so far more of any flex/vibration energy still gets absorbed by the tires and rider at either end of the carbon frameset structure than gets absorbed into the frameset.
And carbon's damping coefficient only goes down as the performance rating (strength and stiffness-to-mass) of the carbon increases.
In the end, I believe carbon forks and frames are stiffer these days than steel framesets of the past, so most of any significant flex and damping has to come from larger, softer tires, which makes claims as to carbon's supposed increased damping sort of specious. Certainly carbon can be made with layers of different materials and bias angles, but not so much the case when lowest weight is sought.
So if wider tires can be aerodynamically streamlined with the right sort of lightweight rims and frameset, and at low weight and modest cost, perhaps the modern bicycle can be a better mousetrap. Some would say that it already is, but realistically the price of the good, light ones tends to be very high.
And carbon's damping coefficient only goes down as the performance rating (strength and stiffness-to-mass) of the carbon increases.
In the end, I believe carbon forks and frames are stiffer these days than steel framesets of the past, so most of any significant flex and damping has to come from larger, softer tires, which makes claims as to carbon's supposed increased damping sort of specious. Certainly carbon can be made with layers of different materials and bias angles, but not so much the case when lowest weight is sought.
So if wider tires can be aerodynamically streamlined with the right sort of lightweight rims and frameset, and at low weight and modest cost, perhaps the modern bicycle can be a better mousetrap. Some would say that it already is, but realistically the price of the good, light ones tends to be very high.
[I've never had a harsh C'dale, and the harshest ride I've had was a Columbus Tenax tubed Schwinn Super Sport.]
08-21-18, 05:16 AM
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I think the hidden gist of the piece is about intellectual property rights, copyright, piracy, etc.
The Chinese simply don't think that way, and don't seem to worry about that conflict.
They have a basic difference here, not a lack of morals in their view.
It's been a non-issue for them for decades. It's non-negotiable.
In time, they get their QA up to par, because it's economically correct for them to do so.
In situations where they're making the frame, bars, wheels, etc for a brand, they see nothing wrong with copying it.
Bontrager stuff is all over the place, and frankly, I can't tell the fake from the real. It's hard to "caveat emptor" without knowing what I'm emptoring.
I think the piece points out, in a way only NPR can obfuscate, that there is often a safety price to pay for the Chinese approach to manufacturing whatever will sell.
The Chinese simply don't think that way, and don't seem to worry about that conflict.
They have a basic difference here, not a lack of morals in their view.
It's been a non-issue for them for decades. It's non-negotiable.
In time, they get their QA up to par, because it's economically correct for them to do so.
In situations where they're making the frame, bars, wheels, etc for a brand, they see nothing wrong with copying it.
Bontrager stuff is all over the place, and frankly, I can't tell the fake from the real. It's hard to "caveat emptor" without knowing what I'm emptoring.
I think the piece points out, in a way only NPR can obfuscate, that there is often a safety price to pay for the Chinese approach to manufacturing whatever will sell.
08-21-18, 05:53 AM
#38
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The transcript implies that the main if not the only issue is poorly made counterfeit carbon frames, yet the Time frame cited in the first example was apparently not a fake. If it was fake, they do not say state it explicitly, leading me to assume it was genuine. So the general theme and logic of the article - carbon fails because fakes are junk - doesn't make sense.
For the C&V crowd that claims that stiffness doesn't matter, there is really no reason to ride carbon anyway. Carbon is far superior to steel in stiffness to weight, but strength to weight is roughly the same as (better) steels.
For the C&V crowd that claims that stiffness doesn't matter, there is really no reason to ride carbon anyway. Carbon is far superior to steel in stiffness to weight, but strength to weight is roughly the same as (better) steels.
Tests can be defined for any failure mode that is understood, thought the tests might not be feasible from a business viewpoint. The questions with carbon composite are, do we understand all the failure modes, and can the failure event be slowed down so the rider has some time to safely stop and get off the bike? With steel frame technology I think the answers are much closer to "yes" than for composites.
08-21-18, 06:17 AM
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I have seen carbon fiber frames being laid up in a very reputable factory. After watching the process, I knew I would never ride a carbon bike. There were simply too many chances for something to go wrong in the assembly process. Small pices of carbon fiber were hand placed in a mold. A bump or a slip by the worker meant that there was not going to be as much material in a specific area as specs required. And once the mold had been closed, there would be no way to check for accuracy or resultant strength.
And as mid night shifts at factories? The real question that ought to be asked is how well the factories protect the designs of the molds. Its pretty easy for someone with a thumb drive to made a copy and have an exact copy of the tooling. Why reverse engineer when you can use the source info? This has happened in other product areas. Can't se any reason it couldn't be done with bikes.
And as mid night shifts at factories? The real question that ought to be asked is how well the factories protect the designs of the molds. Its pretty easy for someone with a thumb drive to made a copy and have an exact copy of the tooling. Why reverse engineer when you can use the source info? This has happened in other product areas. Can't se any reason it couldn't be done with bikes.
Anybody know if there are any mass-production carbon fiber frame factories in North America?
08-21-18, 06:38 AM
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08-21-18, 08:35 AM
#41
Steel80's
From your description, I agree that the tooling is significant. But I think that the technique that successful carbon-layers (is there a better term? The pattern is called "lay-up.") follow is very critical, and subjective. If strength depends on transferring shear stresses between carbon fabric plies, then what connects them together and transfers stress is the matrix, or the plastic, which must penetrate to contact all the fibers. What could go wrong with a misplaced part, a little contamination, or plastic mush that looks like all the other plastic mushes?
Anybody know if there are any mass-production carbon fiber frame factories in North America?
Anybody know if there are any mass-production carbon fiber frame factories in North America?
08-21-18, 08:43 AM
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08-21-18, 09:56 AM
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I've never owned a carbon frame,; having ridden a few I've decided I much prefer steel. I'm happy to ride one, and having a carbon fork on one of my bikes doesn't keep me awake at night.
One thing about this is though that given the frequency - and severity on occasion - of carbon bikes being crashed in pro racing when was the last time we saw a carbon fibre frame fall apart in a crash? I can't recall seeing it happen, and when there is a crash the rider is normally pushed straight back into action on the same bike.
Second question leading on from this is what happens to carbon fibre pro bikes that have been crashed? I can't see any team, even one with Sky's budget just scrapping every frame that's been crashed. The guys riding these bikes are going to work them much harder than I ever could, and they have the confidence in their bikes to go down descents at amazing speeds.
One thing about this is though that given the frequency - and severity on occasion - of carbon bikes being crashed in pro racing when was the last time we saw a carbon fibre frame fall apart in a crash? I can't recall seeing it happen, and when there is a crash the rider is normally pushed straight back into action on the same bike.
Second question leading on from this is what happens to carbon fibre pro bikes that have been crashed? I can't see any team, even one with Sky's budget just scrapping every frame that's been crashed. The guys riding these bikes are going to work them much harder than I ever could, and they have the confidence in their bikes to go down descents at amazing speeds.
08-21-18, 11:47 AM
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08-21-18, 01:40 PM
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08-21-18, 02:12 PM
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From your description, I agree that the tooling is significant. But I think that the technique that successful carbon-layers (is there a better term? The pattern is called "lay-up.") follow is very critical, and subjective. If strength depends on transferring shear stresses between carbon fabric plies, then what connects them together and transfers stress is the matrix, or the plastic, which must penetrate to contact all the fibers. What could go wrong with a misplaced part, a little contamination, or plastic mush that looks like all the other plastic mushes?
Anybody know if there are any mass-production carbon fiber frame factories in North America?
Anybody know if there are any mass-production carbon fiber frame factories in North America?
Note that Time and Colnago use a hybrid mold/assembly strategy. I like that Colnago has used fibreglass insulators and molded in aluminum bottom bracket shells to arrest "squeaking" and electrolysis.
Carbon has been found to be of course a ready path for galvanic corrosion, and in extreme cases, "boils" the resin weakening the structure. No matter how well a two part resin is mixed, there appear to be areas of less than perfect mixing.. so the component parts behave in bad ways.
As to failure avoidance, in the marine industry there are techniques to thermal image and or ultrasound carbon fiber hulls and components to verify construction goals and post incident condition, such as a race course collision or boatyard mishap.. (dropping a boat)
The cost is coming down, but at this point the most effective route is just replacement for the dollar spent.
08-21-18, 05:21 PM
#48
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Although people don't trust the early carbon bikes I have not heard as much about failure. I will never spend a lot of money on a bike anyway so............
08-21-18, 06:13 PM
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My takeaway on the story, to the last line, is that where counterfeit frames are being sold, there is no accountable entity with US assets to go after when a frame fails. For the frame's maker, this means that quality-control becomes a lower priority.
I guess that it's the Commerce Department that is charged with keeping an eye on such markets, trying to keep authentic goods selling at normal prices and with taxes collected at every level. Frames bought from Chinese internet vendors wouldn't seem to be helping the cause, so with NPR's help they can get a few words out about some of the consequences of buying China-direct.
I guess that it's the Commerce Department that is charged with keeping an eye on such markets, trying to keep authentic goods selling at normal prices and with taxes collected at every level. Frames bought from Chinese internet vendors wouldn't seem to be helping the cause, so with NPR's help they can get a few words out about some of the consequences of buying China-direct.
08-21-18, 06:23 PM
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I talked with a guy who told me this almost happened to the Fork on his Trek Madone. The bike was more than 5 years old. Might have been a 2010. He had it in a shop for some maintenance and they discovered a crack in the fork. He was riding it the day before.
Although people don't trust the early carbon bikes I have not heard as much about failure. I will never spend a lot of money on a bike anyway so............
Although people don't trust the early carbon bikes I have not heard as much about failure. I will never spend a lot of money on a bike anyway so............
Lighter riders are far less likely to cause the same failure in the same frame as heavier riders. Riding fast on rougher surfaces would also greatly affect the likelihood of exceeding any compromised frame's limits.
Of course this also applies to bike frames and parts made of any material, including tires that are inflated to higher pressures and chains that are shifted under heavier loading.