rydabent

How much of the weight of a CF frame is the actually fiber, and how much is the plastic resin?

genec

Actually it is a composite.

Carbon fibers are usually combined with other materials to form a composite. When combined with a plastic resin and wound or molded it forms carbon fiber reinforced polymer...

Rollfast

Walmart sponsors TDF?

yugyug

If you want to use the technically correct words, then epoxy is not a "plastic" it is a petrochemical polymer.

But in the common definition, a carbon fibre bike is plastic, as it uses a substantial amount of polymer in its composition.

EDIT: Additionally, carbon fibre itself is made from the polymerisation of a petrochemical host molecule, woven into yarns and then the non-carbon atoms burnt off (carbonisation). So I guess CF bikes are not just part-"plastic", they are fully "plastic."

The interesting thing really is how the word plastic is seen as pejorative, consumers have an inherent bias against plastic materials, for both real and historical reasons, and manufacturers and CF bike apologists avoid the term. I think this is probably not in the consumer's interest. For example, I see a lot of of CF bike adverts spruiking their new technologies in carbon fibre weaving or whatever, but have never seen a manufacturer discuss the chemical composition of the petrochemical polymers they use, even though there are differences between epoxies (and the polymers used are presumably not limited to epoxies either).

That said, it could be that every CF manufacturer is using the exact same epoxy from the same plant in China, so have no interest in discussing it for that reason.

I'll end with my personal perspective fwiw:

Carbon fibre bikes are known in sustainability ethics as "monstrous hybrids" meaning that the materials they use are bonded in ways which have little capacity to be reused or recycled (nor easily repaired in the case of CF bikes). This is in contrast to steel and aluminium bikes. They also have catastrophic failure modes, which, even if unlikely for non-pro riders within the commonly perceived ideal life of the bike, will happen eventually, and sooner than for alu or steel. It can't be ignored that producers push the use of CF bikes as consumer bikes despite this and, intentionally or not, design for obsolescence because their obsolescence drives repeat business - a financial, social and ecological burden. Furthermore, the use of petrochemical polymers supports the petrochemical industry, which isn't great ecologically (though I am aware that steel manufacturing may have a higher carbon footprint - depending on life-cycle analysis - and I certainly believe using petroleum to make polymers is far better use for it than burning the stuff in cars). Regardless, for all these reasons and a few more, I ride steel bikes by ethical, financial and aesthetic preference.

rms13

tell this to all the people riding CF downhill mtn bikes. I still haven't figured out why those bikes don't explode on every run. With how fragile CF is , you'd think those bikes would be one use and throw away

FBinNY 

If you've flown commercially in the last 10 years, odds are you've trusted your life to "delicate" CF composites. I'm not a big fan of CF bikes, but it has little to do with concern about CF strength.

spare_wheel

links please.


recycling:
Specialized launch carbon recycling and sustainability initiative - BikeRadar
Trek Bicycle begins carbon fiber recycling program
Recycling Carbon Fibers from Composite Materials - Siemens Global Website
AERO - Airplane Recycling Efforts Benefit Boeing Operators

a future source of sustainable carbon fiber:
Green Car Congress: DOE to award up to $12M for technologies to produce renewable carbon fiber from biomass
Dr. Barry Goodell - Carbon nanotubes
https://polycomp.mse.iastate.edu/adva...s-from-lignin/
Carbon fibres from lignin - Innventia

rebel1916

https://calfeedesign.com/repair/
Repairs are simple enough and businesses offering such repair will become more common as time goes on.

rydabent

FB

Are you aware that the CF tails have broken of Air Bus aircraft. The one that killed all aboard out of NY was blamed on the pilots for "using too much rudder" which is a crock. At least 3 French Air Bus aircraft have crashed and killed all aboard due to the rudder or the whole verticle section breaking off. Many senior pilots wont fly them or let their families ride in them.

yugyug

Thats good news, I hope it becomes commonplace also.

I suspect I'm still right that CF bikes are trickier to repair than steel - but repair practices in all products are essential. As we see a resurgence in repair practices we will also see a resurgence in durabilities.

FBinNY 

I'm very aware of that crash and the probable cause. I'm also aware of many other crashes due to structural or mechanical failure (and SAMs), and that Boeing, with full awareness if the problems Airbus had, isfully committed to CF aircraft, and has a much higher percentage of CF structure in their newest (and coming) models. Likewise the US military which has been using CF in aricraft structure longer than anyone else.

Does CF fail? of course. Do Steel, aluminum, titanium, and prestressed concrete fail too. Of course. ANYTHING can and will fail for any number of causes including poor design, poor construction, excess loading, and unexpected events.

The real issue with frame and bike failures isn't CF or any specific material, but the crazy drive to build and sell "race" bikes to the general public. Just as we wouldn't expect a formula V car to be suited to the streets of NYC, we shouldn't expect bikes built with not an excess gram to hold up to long term everyday use.

Instead of spewing nonsense about CF maybe it might be more logical to consider the issue of suitability to a specific purpose.


BTW- I gather you don't fly on commercial aircraft.

gecho

I did a little searching and it does look like carbon fiber is recyclable. Since you are no longer dealing with a continuous fiber, they can't be weaved back into a fabric. So they need to be used for different products where those properties aren't necessary or the pretty weave important.

Carbon fiber reclamation: Going commercial : CompositesWorld

yugyug

The first link is greenwashing: there are no new solutions on offer, its merely a call to form a body for 'research' without commitment to funding or practice. The only current practice on offer is down-cycling shredded pieces into filling material, and thats not sustainable in theory (nor in practice because bikes become dispersed within the consumer landscape - a big company like Specialized get behind product stewardship, but they won't unless forced by legislation).

The fact remains that the fundamental materialities of CF make it difficult to reuse or recycle, and thats true with all petrochemical polymers and even more so with polymer composites.

I didn't bother to read any more links, I don't have time. You could write a few sentences explaining your perspective next time instead of just posting links...

yugyug

The problem is not so much that the weave of the carbon fibre gets cut, but that its bonded with plastic, can't be separated easily and then there is polymer length of the plastic. With thermosetting plastics like epoxy there is no easy way to restore structural strength resulting from the initial polymerisation.

Its called downcycling, its not really recycling, and its only economically feasible when dealing with concentrated waste sources. Companies currently don't bother with widely distributed consumer goods (see my last post). Regardless, its not sustainable in theory because the its only a one stop interruption in its journey towards the dump - once its used in this way there are no more options for reuse or recycle (or very limited anyway). Conversely, aluminium can be endlessly recycled with due care. Steel is even better in that it can be recycled, but is so durable that, with care, it may never need to be.

rebel1916

I suspect you know very little about the difficulties of welding modern, thin walled steel tubing.

rydabent

fb

In the center of your last post, you pretty much nailed the truth on CF bikes. The part about selling "race" bikes to the general public. Ultra light weight weight throw away race bikes should not be sold to the public.

howsteepisit

And should we make rydabent the bike czar who decides for us all what bikes should be available to the public? Are you proposing yet another law made by government bureaucrats?

FBinNY 

Close but no cigar. What I said is that is that bicycles designed and built around the needs of racing aren't well suited to general purpose riding. That's very different than saying they shouldn't be sold. It's a free market (last I looked) and there are plenty of choices and folks are free to buy what they want (even if it's not right for their needs).

That has more to do with issues like very limited tire clearance and lack of fender/rack eyes than it does with the material and construction.

Chicago Al 

You could say the same thing, and people do, about cars which are capable of speeds far in excess of any highway speed limits, especially high performance cars where racing and stunt-driving imagery are used to sell them.

As usual, you are dead set against 'government b'crats' infringing on liberties, except things that you have a problem with.

Unless there's an epidemic of CF bike frames cracking in Nebraska and dumping their hapless Fredly riders into rydabent's lap, he should probably find an actual problem to complain about--perhaps there are some kids on his lawn.

BTW I ride vintage steel racing-style bikes. I don't see that I would ever buy a CF bike, it's not the frame but the engine that makes me slow, but it's no business of rydabent or anyone else if I do.

mconlonx

Interesting article. But old -- 2010 -- hopefully things have kicked up a bit. Only downside I could see is that they were only recycling industrial waste, no talk of post consumer recycling except regarding end of life stuff in the aerospace industry. Contaminants are an issue, and by the end of a CF bike's serviceable life, it will be far from clean. Maybe things have changed a bit in the past 4 years, like technology tends to do, but the working recyclers in the article did not address post-consumer recycling.

In the print industry, printing plants routinely recycled paper -- it would go back to the paper mfg, be tossed through the pulping process again, and come out as usable sheets or rolls of paper. But it was only after they found they could market it to all the greenies out there that they started advertising the fact... Post-consumer waste only got going when environinnies pointed out that they weren't really doing anything new and prompted use of post-consumer waste to come up with 100% recycled book papers, including a fairly high percentage of PCW.

mconlonx

Besides, the bike industry is small fry when it comes to being a player in the carbon fiber world. 2200 metric tonnes go into a Boeing -- probably more in one aircraft than any one bike company uses in a year, maybe as much as the entire industry uses.

trailangel

Damn kids:

rydabent

howsteep

Are you going to be my campaign chairman to make me bike czar??

rydabent

FYI for those here, there are two or three people that like to rag me for my opinions. Since my opinions quite often do not agree with their opinion, they burn up their keyboards on personal attacks rather than giving logical reasons why their position is better. Most of them come from the helmet thread, where I am pro helmet use. While I am pro helmet, I am not for MLHs. I guess my problem is I am not the worlds greatest bike handlers like they are, which guarantees that they will never be involved in and accident or go down. Ah well------------such is life.

Bottom line----my opinions are mine and mine alone. Anyone can agree or disagree with them. Either way, I dont care. That is the way I treat other posts and other opinions.

FBinNY 

I understand that you don't care about other's opinions including (especially) mine, and I respect that. My problem isn't your opinions, it's that you keep harping on the same themes without any facts to back them up. Whether it's helmets, and the risk of head injury, the failure rate of CF structures, or MJ use and driving in Colorado, state your opinion ---AS OPINION--- or support it with some facts, but once you've said it a few times stop hammering away at it. As they say, you need to stop pumping when the water is flowing.

BTW- instead of posting the same thoughts so often, consider adding them to your signature line, saving wear and tear on your keyboard, while making sure the message can't be missed.