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Carbon fiber Urban Legend and reality...????(23 posts)

Carbon fiber Urban Legend and reality...????Geof
Dec 16, 2001 8:32 PM
Help me out here... It seems there is a major lack of confidence in carbon fiber overall when it comes to bikes. The Urban Legends of failure, too weak, early fatique, must be a "lightweight" rider, too much flex etc. Seem to be just that: Urban Legends. Out dated opinions based on EARLY design issues. Am I wrong on this? What are the REAL FACTS when it comes to carbon frames, forks etc...?

It seems to me that if an ENTIRE (almost) F-1 car is built out of the stuff, the technology has gotten pretty up to speed on failure rates, flex, stress load etc. I seriously doubt that we feeble humans can exert as much force on a CF fork (for instance) as the complete front or rear end of these race cars turning a corner at 100mph cranking 4-5 g's. Or the monocoque stress of the cars for example.

Just curious how much all the "warning" of carbon problems are truly "problems" or the industry CYAing... So guys and gals, what's the REAL DEAL with carbon fiber.... Not the perpetuation of the "Carbon Fears"

Thanks...
re: Carbon fiber Urban Legend and reality...????Rusty Coggs
Dec 17, 2001 7:24 AM
Recent manufacture CF is OK stuff. Colnago C-40, Trek OCLV, Look, Kestrel, and Calfee being good examples. Most of the bad press IMHO is based on early problems,due mainly to failure of the bonds.Technology has improved.There may still be some cheap unknown brands to avoid, but the big players know what they are doing and doing it well.The rest is just hype and BS form those who don't really know,but think they do.CF forks have nearly become the industry standard.What does that say?
Carbon Fiber reality...TJeanloz
Dec 17, 2001 8:29 AM
What cyclists refer to as Carbon Fiber actually encompasses any number of composite, non-metal, materials. There isn't an industry standard that is CF (like we have standard alloys of aluminum, steel, and titanium). I don't think anybody doubts that CF is very strong- and offers strength-to-weight ratios similar to or better than most metals. Any number of outside of cycling examples attest to this: F-1 cars, general aviation aircraft, business jets. The wing of a jet takes a bit more force than your average OCLV.

But the question becomes, are the people building the bicycles as good at utilizing CF as the people building the aeroplanes? We acknowledge that CF 'can' build a great bike- but the question is, is it a great bike just because it's carbon fiber? The answer is, of course, no. So the conclusion we draw is that good, long term builders (Trek, Aegis, Calfee, Kestrel, Colnago) build a good product- because they've done the trial and error. But Taiwanese shops that put out a carbon bike because the market will buy carbon bikes- I think there's a reason to be nervous.
re: Carbon fiber Urban Legend and reality...????grzy
Dec 17, 2001 9:31 AM
Stick with established mfr.'s and brands and you shouldn't have a problem. My personal experince is that a good CF frame is pretty damn tough - even in a crash. Does that mean that it can't fail? No, it 's all a matter of what the design objective was and how well it was built. Anything can be over stressed - it's all relative - you don't need to be doing 100 mph and pulling multiple g's. I've been using a lot of CF components wavesiling on the Northern California coast for years. I've had some masts that have with stood over six years of total abuse during which I have destroyed lots of aluminum components, sails, boards and even my shoulder. The rub is that CF allows you to make things stronger and lighter, but often times it's the desinger will come too close to the design limit or else things get overlooked in the manufacturing process. I even build my own boards using CF and vacuum bagging techniques.

Be very wary of half-assed designs offered at "bargain" prices. We should start seeing an increase in CF failures as the market becomes flooded with low-end carbon components. The one bad thing about carbon is that failures usually occur with out warning and are both sudden and catastrauphic.
Failure rate...geof
Dec 17, 2001 10:08 AM
I wonder though how much failure there actually is out there compaired to the #'s of frames, forks, posts etc. I see lots of interesting opinions (mostly nagative) on the CT2 post by easton for example. It seems there is a band wagon effect in place here. I've got one on both of my bikes and I weigh in at around 195 or so. I've never had a problem.

The other question this whole topic raises is user failure IE: incorrect installation etc.

I wonder how many people have actually seen a recent carbon post, or fork completely fail from a manufacturing problem.

Again, I'm playing devil's advocate sort of here, because it seems I'm always seeing overall bad press for CF parts, yet they are becoming the industry norm to some degree. Is part of the mentality a "if it's not broke don't fix it" sort of thought process or the purists scoffing the "new" thing.

I do agree that the junk is and will be a problem in the future. It's difficult to say what this will bring to the industry. Kind of like a Ti Huffy....
CFDog
Dec 17, 2001 10:17 AM
I've had 2 CF components fail on me. One, an all carbon fork on my 2000 Bianchi EV2; I think it was made by Advanced Composites; it shredded at the top of the headset.

The other was the carbon part of a Campy Record 10 rear derailleur. The carbon broke right at one of the pivot pins, sending the whole mess into my spokes. Luckily, I was going slowly at the time.

Remember that carbon race cars are not mass produced. They are made and tested by hand, each carefully inspected. Mass produced bicycle forks are not held quite to the same quality standard. Also, an F1 front wing alone can cost $20,000.

I suppose someone could equally fear aluminum, too. I've broken or seen broken all sorts of aluminum parts.

Dog
Wow, how did the steerer break? What happened? nmGeof
Dec 17, 2001 10:39 AM
nm
probably used a star nut instead of plug - nmJS
Dec 17, 2001 11:56 AM
I don't think so,TJeanloz
Dec 17, 2001 12:05 PM
I can't speak for Doug, but I don't think that was his problem. We sold quite a few of those forks, and a few (I think 3) of them broke at the steerer tube. They all gave plenty of warning before they broke, and no injuries resulted.
questiongtx
Dec 17, 2001 12:53 PM
hey TJeanloz, I heard something about King threadless headsets putting undo pressure on the steerer, something to do with their design and the way they got around paying to use the Aheadset patent. I heard that with carbon steerers it's better to use an actual Aheadset licensed design (Campy paid to use it, right?). Thoughts? Any truth to this?
questionTJeanloz
Dec 18, 2001 8:44 AM
I hadn't heard that- but it wouldn't shock me. I've never been a huge Chris King fan- and I understand what people are saying here. The King No-threadset doesn't use the same compression system (with a conical washer) that an A-Head uses. Anybody who's installed the King knows how tightly that their top ring fits onto the fork. I think that ring could put undue pressure on a steerer tube, but that's PURE speculation. I haven't seen any factual evidence that more forks fail with King headsets than traditional A-Headsets.
thanks! hey Dog!gtx
Dec 18, 2001 9:42 AM
hey Dog, you stated that "it shredded at the top of the headset"--was it at the top ring of the King hs? Maybe it is speculation, but it is interesting. I assume the Campy Aheadset doesn't do this...
Hmmm...g-money
Dec 18, 2001 10:16 AM
The compression ring on the King only goes over the tube and the pressure is applied downward to make the adjustment. Considering it's placed by hand I can't imagine it putting any more stress on the steerer than the Aheadset. The compression ring does not tighten around the steer tube. The aheadset comp ring does tighten, however. So it would seem the King would actually be better from a constricting point of view.

just a thought.
no star nutDog
Dec 17, 2001 2:13 PM
No, it was with the Bianchi-provided expansion nut and a Chris King headset, both installed by a shop that time. It was also using a Cinelli Grammo Ti aheadset and no spacer, which could have contributed to the failure.

Incidentally, the break was sort of a shredding at first, which allowed me to carefully steer the bike home a few blocks.

Dog
yes, that's...gtx
Dec 17, 2001 3:54 PM
why I'm curious about this possible King HS connection. I can't find it now, but I think I originally saw it posted (possibly by Anvil?) way back in the mtbr.com roadies rejoice days.
re: Carbon fiber Urban Legend and reality: threadlessTxTarpon
Dec 18, 2001 2:18 PM
Here is a question:

If I have a carbon fiber fork with a 1" carber steerer, what would be the best way to go:

a) with a clamp on stem

or

b) quill
duh...C-40
Dec 18, 2001 2:23 PM
It's impossible to use a quill stem with a CF steering tube. The inside of a carbon tube is a lot smaller than the 22.2mm quill.
duh...TxTarpon
Dec 18, 2001 3:02 PM
I read a post where on here where it sure sounded like the guy dropped his threadless for a quill.
duh...grzy
Dec 18, 2001 3:57 PM
In addition to debating if it fits or not you should bear in mind that the CF steerers are designed to be clamped from the outside by the stem. And some are even particular about which clamp-on stem you use - avoid the ones that "point load" the CF. There aren't too many people that woould advise you to do otherwise - unless you don't live dangerously enough.
sort of tough to thread CF, too, isn't it? nmDog
Dec 18, 2001 5:00 PM
CF is an engineered materialDrD
Dec 19, 2001 4:36 AM
Keep in mind that carbon fiber is an engineered material - much moreso than the slew of aluminum, titanium, or iron alloys commonly used in bikes - in other words, it's properties are nearly entirely a function of the design work which went into them, and the care taken in laying things up - mistakes or cut corners in either area can cause big problems later. With CF you really get what you pay for - the example of an F1 car chassis is a good example of what can be done with CF, but not necessarily indicative of how all CF items perform - sure it's CF, sure it's freakishly light and strong, but they cost way more than a couple grand - orders of magnitude more - both in manufacturing cost and design work.
We make good Carbon fibre framesTaiwan Joe
Dec 22, 2001 9:33 AM
Here in Taiwan we are working hard to make carbon fibre bicycle very cheap for you. Some have said here that our process for manufacture not so good but we are here to tell you they are crazy!

We are the champions of mass production. Once we make damn good carbon fibre product, why we need to look over that thing with people so much? Our machines are good and they know what they are doing. Much better than depending on foolish people who can have a bad day at the home and take it out on on your bicycle. Bad person could leave you badly hurt or even cripple because of argument with spouse.

You no need to worry about anything like that happening to you with bargain Taiwan made carbon fibre frame. Not only will you be very safe as you ride the bike, but you will be saving lots of your dollars. Now that is a bargain at any price, I think.
Hey, Taiwan Joe,guido
Dec 23, 2001 6:16 PM
Ten years ago Giant was the largest factory in Taiwan, making bicycles of every type that were marketed in all parts of the world. I remember when Giant entered the US market in the early nineties, their product was admired along with some Japanese marques, such as Fuji. Since then, they have entered the serious racing market, sponsoring a Euro team, their bikes racing head to head with the best Euro bikes. Now, a recent thread at this site asserts that Giant carbon fiber bikes are the best for the buck.

Just out of curiosity, what other kinds of bikes does Giant now build, and what markets do they address? I also heard that for a time, Giant built low end Schwinns, and possibly Bianchi's and other familiar names marketed in the US. Can you enlighten us on current Taiwanese output of names familiar to Americans?