Can anyone enlighten me as to the difference (if any) between a carbon fiber frame, carbon monocoque, and a carbon composite. Are there real differences or is it all just different ways of saying the same thing?
Man, I just typed this huge, long, answer to this and it got lost in cyber space.
Damn. I’m gonna go get some coffee and try again. Sorry.
There are so many methods to build a frame. Some people will call a one-piece frame a monocoque, and the term is somewhat misleading. One could call the BP Stealth (or Martec superbike) a monocoque, but it is two halves glued together. But it IS a monocoque from the shape of it.
The old Kestrels were true one-piece bikes, which made them very expensive to produce anything more than two or three sizes. The modern ones are two halves, the front triangle is one (or who more; who knows?) piece, the rear is the other piece. I would wager that the front and rear triangles are two separate halves. But it is all fused together, so it could be a monocoque.
Then you have tube and lug frames. Trek OCLV looks like a “one piece”, but it is a set of lugs with tubes glued in. The lugs are carbon, as are the tubes. Trek fashions the joints and lugs to where they are nearly seamless when bonded together.
In actuality, one could term ANY non-faired bike as a monocoque, as the “internal” frame and external aspects are all one. An old steel Huffy is a monocoque, if you know what I mean. It all comes down to definition and interpretation. Some would only say a monocoque is by definition a bike with a shape like a Corima Fox, Martec Superbike, Zipp 2001, Softride Power V, or a Lotus Sport 110. That’s your call, as some magazines have called the Trek OCLV a “monocoque”.
Carbon composite is the construction. Nothing can be 100% carbon unless it is carbon/carbon. Most companies worth their salt can get 50/50% carbon to epoxy, some can get 60 carbon/40 epoxy, and I have even seen claims of 70 carbon/30 epoxy. But “composite” can also include aramid fibres and fibreglass, as well as nano molecules of carbon to toughen it up. But the technology on bicycles and non-motorised sporting goods will more than likely be only carbon/epoxy (and whatever else the hell they want to put in) composite. Carbon/carbon is a very complicated process that only aircraft manufacturers, and other super high-tech companies that charge a LOT more than what you can buy on the market now. And yes, carbon composites can be made in your garage, unlike carbon/carbon.
One other thing- SSG (sliver surface graphite) is not graphite AT ALL. It is texalium, a product from Hexcel composites.
So to answer your question: yes and no. People will term it what they want to term it, and one would have to pick the manufacurer’s brain to figure out what they are really selling. But it IS a carbon frame if everything but the dropouts (and other requisite metal parts) are made of carbon.
I hope my answer was slightly clearer than mud.
beatcha to it. ;^)
Your answer may have been better than mine…
A ‘carbon fibre’ frame is a generic or general term for a frame made using any of the various types and styles of manufacturing using carbon fibre.
A basic description…
A ‘carbon monocoque’ frame is a frameset manufactured as basically a single composite structure. This style of frame is made using a mould with the carbon fibre laid into the mould in various directions and thickneses to achieve various strengths where required. The inside of the frame is either filled with an inflatable bladder or foam type core to press the carbon and epoxy against the mold to remove air whilst curing.
Benefits of this type of frame are the various shapes and designs that can be formed, they are basically up to the imagination. Problems with mold costs, manufacturing time and problems carbon layup and weaknesses in the carbon curing process can make them expensive.
Common brands are Kestrel, Cervelo P3C, Giant, Trek et al.
Bonded Carbon tubed and lugged frames.
Carbon tubing, like fishing poles, are made up by winding carbon in various directions and grades around a mandrel. Extremely high strengths and light weights can be achieved with this tubing. You can then use either carbon or alloy lugs to laminate or bond the frame together. Bonded frames use lugs bonded using high strength glues to bond the carbon tubes to lugs.
Frames can also be layered up similar to a monocoque style to achieve light weights with high strengths. Bonded lugged frames, using alloy lugs, have been around since the 80’s with Look and Vitus both having alloy lugged bonded carbon frames out many years ago
Frames built using this style are often lighter and ‘stiffer’ than monocoque framesets however the designs are mostly limited to double diamond styles.
Common manufacturers are Calfee designs (Best in my opinion), Kuota, Colnago and many others
You also have alloy, Ti steel or alluminium, frames with Carbon tubes, or monocoque stays etc, used which are bonded into the frame.
OK, I’ll take another crack at this: “Carbon fiber frame” is a term generically applied to frames that employ any number of materials and combination of materials that make up carbon fiber. There are a number of different materials, construction techniques, etc. “Carbon monocoque” describes a carbon molding technique use to make frame components. There are very, very few completely one piece, from front to back, monocoque frames. Most monocoque frames, such as older Kestrels, used a forward “fuselage” comprised of head tube, down tube, top tube and seat tube that was then joined to a right and left half of the unified seatsty/chainstay assembly- In other words, monocoques are generally molded as three to five frame components, as opposed to being comprised of tubes. Monocoques aomtimes employ a molding technique known as “bladder molding”, where an inflatable bladder holds the carbon fabric against the outer surfaces of the mold space, is deflated and partially removed after molding. Monocoque construction, like all other techniques, has it’s strengths and its drawbacks. “Carbon composite” is a term I like since it speaks to the “combined” nature of carbon fiber materials used in bikes. In general, carbon fiber used in a bikes is a “composite” of different materials that may include such things as Spectra, ceramics, polymers (plastics), Kevlar or any number of other fabrics/materials/fibers to alter the characteristics of material so the building can get the properties they want.
It is worth saying that carbon fiber is a difficult material to generalize about. It is so “engineerable” and “tuneable” that generalizations about it simply don’t ring true- they can’t be applied across the board.
Each carbon material and construction technique using that material is unique.
Hello,
I not disagreeing with the previous mentioned explanations, but their are som,e problems with how the bicycle industry uses terms. So here goes:
Can anyone enlighten me as to the difference (if any) between a carbon fiber frame
Saying a carbon frame is meaningless. No such thing exists. Their are many frames made partially using carbon. These typically use carbon fibers, mixed with other types of high strength fibers, held together with some sort of plastic matrix
carbon monocoque,
A bicycle frame made of carbon fibers and plastic matrix molded in one piece. This is a very difficult way to make a frame and is rarely used. The most common method used to make carbon composite bicycle frame is to make 2 or more pices then fasten them together. Their are many ways of doing this. The most common method is to make tubes out of the carbon and plastic then bond them together using lugs. The lugs can be metal or carbon/plastic.
Carbon composite is the same as saying carbon mixed with something else. All “carbon” bikes are carbon composite.
Styrrell
Man, I just typed this huge, long, answer to this and it got lost in cyber space.
Thanks for all your replies. It does clear it up a bit for me. So, carbon means different things to different manufactures. Unlike with a steel frame, the name says it all with ‘carbon’ the lines blur a bit. HRH, you are right clear as mud.
Steel frame manufacturers ‘blur’ the lines just as much as everyone involved in the bicycle industry. It is all a big game of lies and more lies all wrapped around very limited true science.
What is carbon fibre, according to google:
http://www.designinsite.dk/htmsider/m0632.htm
www.f1technical.net/glossary.php
www.hartside.com/dictionary.html
homepage.ntlworld.com/garyc/tips/glossary.htm
What is a good in an ‘alloy’ bicycle?
It gets even worse when you venture into Alluminium alloy bicycles:
http://www.bikeforums.net/archive/index.php/t-15193
http://www.cyclingforums.com/t29639.html
Is Reynolds better then Columbus?
Everything in the bicycle industry is based around half truths and faith, people buy based more on marketing than science or race results ie: No single bicycle frame is so fast it will win every event regarless of the rider.
Take a loom at posts from people on this forum, uhmm Tibbs et al, who are faith based more than knowledge based, hence they will pay a lot of money for a frame made from cheap materials believing it is better than having real scientific proof ie: wind tunnel tests, materials quality etc etc.
One other thing- SSG (sliver surface graphite) is not graphite AT ALL. It is texalium, a product from Hexcel composites.
Is this the stuff that is sometimes called “white carbon”?
It could be, some of the white carbon is “normal” carbon colored white.
Styrrell
a very impressive design. wish I could afford one of these frames…
A good friend of mine asked me once why the bike industry is one of the very few industries where people recommend/claim a products is good before it is even released or has any real race results.
Next time I will forward your email address!
“white carbon” is not carbon fibre AT ALL. It is fibreglass with aluminium oxide sprayed onto it. It is actually pretty cool, as you have that fibreglass barrier between it and the carbon frame when used as a cosmetic layer.
For no reason other than they make arrows like this, do Easton make a carbon frame with an aliminium core?
I couldn’t tell you the answer to that question. I don’t believe they do frames (yet). One can get an anodised blue alumitex hockey stick from Easton, as well.
But yes, the aluminium oxide is merely sprayed onto the fibreglass farbic.
Easton doesn’t make carbon frames at all, I believe. They do make carbon tubes and other carbon bike parts. In the past companies have made bikes like you describe.
Styrrell
Yes, the one whose parent company was Exxon made one with very thin aluminium tubes with a carbon wrap. They were pretty deplorable, then got reliability in it’s last year or two in production. It was to never be seen again…