"According to my LBS..."

That's where most myths get started ;-)

BS.

Start with some of the facts. Do a google search on carbon fiber and on carbon fiber manufacturers. A top industry one is Torayca who makes carbon fibers for Felt, Kuota, Kestrel, Isaac and almost every other nice quality carbon bike.

When you finish your on-line survey of carbon fiber then you can return to your bike shop and educate them so they no longer spread less-than-truly-informed generalizations.

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Tom Demerly
The Tri Shop.com

I don't know about sources of carbon fiber, but there are big differences among the CF frames built by different manufacturers, just like there are big differences among steel, Ti, and Aluminum frames. There are all sorts of things you can do to dial in or screw up a bike made of any material.

While Tom has already pointed you inthe right direction, I will say that there may be a little bit of both. Take for example Giant Bicycles - while we would be hard pressed to dispute that this company is a leader in the manufacture of light weight, quality carbon fiber framsets, is this a fate or a by product of the the parent companies other subsidaries? Giant's parent company in Tiawan also owns an aerospace manufacturing company that makes a good number of the composite aircraft structures/assemblies for both Airbus and Boeing as well as a number of top defense contractors around the globe. I have always argued that Giant enjoyed an advantage due to the benefit of having access to 20-25+ years of aerospace composite manufacturing techniques. My understanding is that a few years back, Trek even sent a samll contengent of its manufacturing engineers to Giant's facilities in Tiawan in order to research Giant's composites manufacturing process with the goal of improving the OCLV process.

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¯\_(ツ)_/¯

It is true that the market for carbon fiber is tight currently. The aerospace industry was already taking up a fair amount of composite materials (a lot of which are going into the 787 and aerobus's new model) and at the end of last year the government pretty much sucked entire grades of carbon fiber off the market (for ballistic panels is my understanding.)

That having been said, I don't think that the supply is the main cause of any differences you would see between "quality" and "cheap" manufacturers; it is probably more of a difference in design and material selection.

partially true, true in the part that carbon is a little short globally right now, and part that better bikes usually use higher performance/quality carbon fiber than cheaper bikes. This is usually affects the price point and weight of the bikes not the strength. I'm assuming that the design process for bikes goes something like, need factor of safety X, with nice high modulus carbon and super new nano-charged resin bike frame ends up weighing 2lbs, but if you use cheaper lower modulus carbon, lower end resin, and don't engineer your ply layups all that carefully you end up with the same frame desing weighing 3lbs.... In a lot of ways you get what you pay for. Hey on ebay you can find full carbon/glass frames for under $100! oh, btw they also weigh near 6lbs for some of them:)

It is partially true. As Tai said, there is a much greater demand for top quality (read: high-modulus -- this means each individual strand of fiber is longer, so you get a stronger piece with lower weight) carbon fiber than can be filled at the moment. There is definitely a truth to the "grades" of carbon. For example, there actually will be a difference between a Trek OCLV 120 vs OCLV 110 frame. And yes, the big aerospace companies do get first dibs.

Certainly, you can be sure there is a difference in the fiber used for a top of the line frame and what you get in a water bottle cage.

However, carbon fiber is not "very difficult to find." There is a just a price premium at the higher end right now.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

I agree it is both. there are as many variables in carbon fiber as there are in metal alloys. Add in the different weaves, resins, and layup processes and you have an almost infinite number of veriations in 'One' substrate.

Bottom line - Not all Carbon Fibers are created equal, thusly neither are the bikes made of them.

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This is your life, and it's ending one minute at a time. - Fight Club
Industry Brat.

I was talking to my brother who works with composites in aerospace about carbon fiber and he made the comment that the resin is an important part of the process, equally or more than the carbon. Resins that can be used in small amounts (ie. moulded under pressure to produce stiffness and low weight) are very expensive. You have to use more or the cheaper resins so that adds a lot of weight.

Never make the mistake of assuming that divisions in the same parent company work or even talk together, this is not always the case. It really varies company to company. They might enjoy a bulk discount on raw material purchasing but I'd want evidence before I assumed further.

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"Knowledge is good" - Emil Faber

I know a person that makes parts for Boeing and the government and I can tell you that the fibers that they use do not compare at all with what higher end frames use, but the difference between the way the materials are woven and molded at the very end I think that there is little difference in how a frame would handle or feel such as riding with tyres inflated at 125 psi vs 124 psi. The same is true for high grade Ti. Right now the govt. has its hands on all the high ends supply that it can get.

mmm, not really what high modulus means:) long or short fiber, it usually just depends on how the cloth is laid and cut. The only time that fiber length would come into play is when possibly wrapping over joints and such and in some of the older type chopped fiber or thermoplastic (GT frames) bikes or possibly the filament wound tubes in some frames. The high modulus refers to high Young's modulus I believe (don't quote me here) and basically means better material properties in the tensile strength realm. But the weave of the cloth makes a big difference too, as well as how the fiber is processed and finally how carefully the ply lay-up is engineered and manufactured. And then resin, that's a huge differentiator as well, I have a pint jar of resin on my desk right now that cost $180! The stuff we usually use is a LOT cheaper but it all depends on the application. Want to throw in some nanotubes for some nano reinforced resin? We make our own but sometimes we buy nanotubes and a small vial can cost more than a bike frame! And then how you manufacture, getting the pressure right, the cure cycle right, getting optimum compaction, minimal voids, complete fiber wet-out, making sure the mold release works. Ugh, that's why I don't work in our carbon lab very often:) I like working with metals so much more!

"there actually will be a difference between a Trek OCLV 120 vs OCLV 110 frame."

Not a huge difference. 160 gms off a frame. Here's Trek's description of the two materials.

OCLV Carbon 110 was specially engineered to help Lance Armstrong defend the Tour de France. This frame has been designed to be as light as possible. Trek was able to reduce the weight of the frame 160 grams for the 110. This may not sound like a lot, but when it comes to a competition such as the Tour, ever gram counts. Trek has optimized the amount of OCLV per square meter (110 grams) and has added high modulus carbon to create a rame that's ultrastrong, ultrastiff, and ultralight.


OCLV Carbon 120 -- The 120 is a stiff, strong frame with excellent ride quality that weighs 100 grams less than the original Tour winner. It uses 120 grams of carbon fiber per square meter, hand built into a comfortable frame without compromising its strength and stiffness. The result is a high-performance bike ridden by the USPS team.

Weave is very important, but weave has nothing to do with the term "modulus." High-modulus comes from, generally, the heat-treatment process. A higher-modulus fiber ends up having better fiber alignment (you can think of carbon fiber on the microscropic level as tiny sections that are stuck together by friction, similar to velcro in a way). The better alignment is what results in a higher modulus. So, when I refer to length of fiber, I am not talking about the length of a strand, but rather the length, on an effective microscopic level, of the fibers based on orientation.

And, FYI, Young's modulus is NOT related to tensile strength. Young's modulus is related to stiffness. The carbon with the highest tensile strength is NOT the carbon with the highest modulus. Highest strength comes from a lower temperature heat treat that for highest modulus. This is why fiber "length," or more technically accurate, consistency of orientation on the microscopic level, is so important for high-modulus fiber. The "longer" the effective fiber, the stiffer the resulting strand.

All of the other things you mentioned play a huge role in determining how a product works. But since you can do all that equally well with any sort of fiber (weave it, cut it, lay it up, etc.), you really do need to start at the very beginning -- what "carbon fiber" is on a fundamental level -- when talking about it.

And for cerveloguy, 160 grams is definitely insignifcant. That is close to 10% lighter for a frame. That's a lot. And the OCLV 55 bikes will be even lighter still. That is almost double what Cervelo shaved off by switching to anodizing on the "SL" versions of their bikes. I guess it really depends on what you consider to be significant, though, and it is nothing compared to what most bike buyers could lose of their stomach. :)

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Most fibres are made in the 3rd world. Yes, even the stuff in aircraft is 3rd world.

what you really need to examine is method of construction. Composites can make for turd polishing. Torayco fibres can be used and you still can have voids, etc. carbon can be bought at a few hundred $ per pound. It all depends on who builds it.

"And for cerveloguy, 160 grams is definitely insignifcant. That is close to 10% lighter for a frame. That's a lot."

Is this a typo? I think you meant "160 grams is definately significant" ??

I'll again say that it's not significant in the over all picture. Although 160 gms may be 10% weight improvement on an already lightweight frame, it's very little in the total weight of rider & bike.

Also with today's lightweight components and a 15 lb minimum race legal weight limit it's quite easy to still have a 15 lb bike even with a "heavy" frame.

Oops, I had a "not" nestled in there that seems to have gone into hiding.

I'm an admitted geek, so while in the overall scheme of the things, the weight is obviously meaningless, when you think about the fact that they can make a light frame 10% lighter, that is astounding to me. I am personally not a weight weenie (i.e. I would not pay the extra for the lighter frame), but I am constantly amazed at how the bike industry pushes the limits on weights. Like I said, it all comes down to how you define and perceive significance.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

I hear ya. But have a read of this essay. Kind of puts it into perspective.

http://www.torelli.com/tech/weight.shtml

Nice article. That makes me feel way better on my heavy (20 lb) softride.