cyccommute 

The problem with Kevlar is that it highly susceptible to UV degradation. The exterior coating protects the Kevlar somewhat but not completely.

The polypropylene is about 1.5 times lighter in terms of density but since the article implies that it is used in greater quantities in the frame.

bmthom.gis

C'mon folks, you know that after the nuclear holocaust the only bikes left around will be old Schwinn Varsities and sturmey archer hubs!

Maelochs

So .... your advice to people considering what kind of bike to buy, is .... Wait a decade?

Not even going to get into the purely personal meaning of "better."

Here's the news: materials science is a big field, and growing quickly.

I am sure a lot of people have noticed, only a couple of bikes are made out of wood anymore ... and maybe some have noticed, steel has improved a lot in the past century ... Aluminum, CF, and whatever is next .... are all coming.

I have no problem with people trying to cling to the past ... it is a normal reaction when people get scared, or get old an inflexible.

Ten or twenty years from now all but the very tiniest number of bicycles will be composite, entirely, and will be lighter, stronger, and more durable than anything produced today ... and most of the parts will probably be made in some kind of 3-D printer and put into ovens by robots ... Each frame having been custom engineered to the exact dimensions of the rider.

Those of you still alive in 20 years to see this ... will still be trying to explain why your $20 K steel bike that you just got 20 years after you ordered it, is "better."

I know progress is scary ... wouldn't it be great if age brought wisdom, automatically, instead of closed-mindedness and crankiness?

cyccommute 

Well the old Schwinn Varsities may still be around but even cockroaches have standards. The cockroaches will be riding titanium bikes and eating the carbon ones as fuel

cyccommute 

Depends on what you are considering. If you are considering all things...including durability and longevity...carbon may not be the best all around material. It's the best for some applications but not all. No material is the "best" for "all" applications...not even steel or titanium.

The idea that carbon fiber (or any material other than steel) is going to shatter into a million pieces and leave you bleeding in the middle of the road is an old one that needs to be put to rest. Yes, frames sometimes break...of any kind of material. Yes, you can find videos of carbon fiber or aluminum bikes breaking. But that doesn't mean that steel never breaks or that the other materials are prone to failing catastrophically. It just means that someone was around with a camera to record the carnage. You probably won't find too many videos of the pros breaking steel frames because everything wasn't recorded when steel was prevalent under pro riders. Steel isn't even that prevalent under the rest of us any more.

I've seen carbon fiber that has broken. It didn't "shatter". It breaks like a stick of wood. That makes sense if you know anything about the material since it is laid up as a fabric that is woven. Try "breaking" a piece of cloth.

While I agree with you that carbon is probably not something that is built in Chinese slave factories as it is an extremely high end product, I have to disagree with you that the posted video makes your point. First off, any tube damaged in the manner that those tubes are damaged is compromised independent of how little or how much the tube is damage. It may take more force to damage some of the tubes but all of the damage shown is catastrophic.

Secondly, I think you are misrepresenting the results. The final composites that are tested are foam filled carbon fiber composites which aren't the carbon fiber used in bicycles to my knowledge. Bicycle carbon fiber frames are more like the Kevlar and "conventional" carbon fiber tested at around 1:10 in the video which obviously perform the worst of all the material with respect to impact resistance.

The composites that perform well are foam filled which is unlikely to be used for a bicycle frame where weight is a usually a greater consideration than strength. But that's a trade off we usually make when it comes to bicycle frames, no matter what material is used.

cyccommute 

I doubt this material is that much cheaper. The research being done at Oak Ridge might drive the price of carbon fiber down but currently the price is driven by the cost of making the fiber and the demand for the fiber. The demand is being driven mostly by aeronautical applications right now.

The cost for bicycles is being driven by the production cost of the frames and it's the same reason that steel or titanium frames from a custom manufacturer cost so much. Most of the work is still done by hand.

John_V 

I really didn't have a point to make since I never posted my preference of materials. My post was a respond to the guy whose post made absolutely no sense. The steel vs aluminum vs carbon fiber argument is really pointless because people will believe what they want and a forum discussion most likely won't change their mind. Any frame material will break under the right conditions but it's hard convincing people of that when they only see things one way. I have aluminum and carbon bikes and, like tools, each is used for their intended purpose.

I wasn't representing anything with the video other than posting it so people can draw their own conclusions. The two carbon tubes were filament wound and not layered sheets, the carbon used in bike frame construction. Filament wound is made from single strands of carbon thread wound into the resin. There are some videos on YouTube that show the process.

ColonelSanders

You will soon discover that is just one of his many charms.





All these threads which may seem like just going over the same old ground every time, has allayed my fears about carbon bikes, so I can definitely see me having one in my medium term future.

fietsbob

This will be better by being argued over and over until spring?
when you can finally go ride what ever you have..

crank_addict

And the 'coefficient of friction' has begun.

Suits fly as LeMond Composites fires its CEO | Bicycle Retailer and Industry News

Leebo

In 20 years I will still be riding the 5 steel bikes I'm riding today. YRMV.

Kindaslow

I can't imagine riding the same bikes for twenty plus years. 😀

fietsbob

I still ride the DIY frame build of steel I did 42+ Years Ago. it was a light touring design, they don't go out of Style..

Like the heavily trend mongered Racing Bike of today's Stars Does..

Kindaslow

I love riding the bikes and playing with the new tech, too. Nothing wrong with keeping your bike until death do you part (or get buried with). I plan on 3-5 years per bike, but might keep my SS MTB. I am getting older and it might stay with me until I cannot ride it on real trails.

hotbike

I didn't read the article, but I'm aware of the carbon nanotube technology...
But I'd like to interject a comment. It seems to me, a word has disappeared from the vocabulary, which we heard much more frequently in the 1980s... That word is COMPOSITE. We can mix carbon with other materials, including Epoxy ( of course...), as well as Fiberglass, Kevlar, Ceramic, Foam, Microspheres, Spectra, and Honeycomb...

I hope builders have more knowledge, rather than simply having the word "Carbon Fiber" in their heads. F

Frame tube diameter, frame tube wall thickness, tension, shear, and compression, as well as Ergonomics are important in building bicycle frame.

rydabent

Probably on the internet, so it must be true.

Juan Foote

I, for one, am glad to see improvements being made in composites. Along with all these applications...it does amazingly well for prosthetics as well.

I trust my well being and safety to a big chunk of carbon fiber socket and what has so far been an absolutely amazing plastic foot for the past several years. I am glad to report that it hasn't given any issues and look forward to a later generation that is stronger without the need for the thickness and weight.
In my years walking on these things I have had one break, and it sort of crumpled and stretched, thank goodness. My cycling leg has been through a couple of crashes and still going strong.

Leebo

Do you just throw them away after a while? Lets take my Surly 1x1. Has seen a sus fork and a rigid one. Pedaled it 1x1, 1x9, 3x9, double dingle speed( don't ask) and now 2x9. Fits 3" ( thats right) 26" tires on 35 mm rims. And 26x2.5 slicks. Now sporting 29er x 40mm studded tires. With a rack and frame bag sometimes too. Most of the time a riser bar with bar ends. May set it up for bikepacking soon. 26x2.8 tires with front sus and some frame bags. Variety is the spice of life. YRMV.

Kindaslow

I tend to make someone very happy each time I sell a bike, that is what occurs. For me, the spice is a new bike and new tech, then modifying that bike to my wants. I cannot picture variety via the same bikes for 20+ years.

Leebo

^^^^^ Sure upgrades are great, Working on a new wheel set for my 2013 enduro. Got a fork/cartridge overhaul this winter too. 10 bikes or so now. Don't sell my bikes. Use until they break or such. Some end up as a commuter. My 2001 rockhopper is now a winter commuter. Once I get a bike dialed in, tend to just ride it. Got 16,000 miles or so on my rear wheel for the cross check. Replace parts as needed.

DomaneS5

Transparent Aluminium

berner

I've worked with composites for a good part of my life. In one of my more recent jobs we built a structure for drop tests and a series of panels, about 2 square feet each and dropped a 50 pound weight on them from 20 feet. The panels were solid glass with vinyl ester resin and they all suffered serious damage. The best performing panel was vacuum infused with a rubber additive to the resin, (rubber toughened we called it).

In tests of my own, I made several test panels with 1/8" high modulus E glass cloth each side. One sample was with balsa core and the second was with a foam core. I had a friend fire a 38 caliber revolver at each sample. The foam core absorbed the impact so that the opposite side showed no sign at all.

In a high tech application of the resin infusion process, a company I worked for produced carbon fiber inlet ducts for the engines of the old U2 spy plane. Although superceded for spy purposes by satellites, the U2 was still a very good platform for photography and NASA used it for mapping I surmise. The plane could be deployed where needed and moving a satellites' field of view is a big deal.

The interesting thing about those ducts was the level of quality control of the process demanded by NASA. The epoxy itself was very fussy, being highly reactive, building up heat very rapidly after mixing and actually smoking before the ducts were infused. On one occasion the resin began smoking filling the shop with noxious fumes. The shop build a custom machine that mixed the epoxy and dispensed it into a container in small amounts. That container was used with a digital thermometer with the probe in the resin and a continuous temperature reading. You could see the temperature of the resin almost instantly begin to climb with too much resin in the container.

A separate test panel was infused simultaneously with the part that was later tested and when the part was trimmed to size, cutoffs were saved for further testing. Over time we made test parts for Boeing, McDonald Douglas and the Navy with procedures often spelled out in detail. I have no trouble with carbon fiber as a structural material for bikes but I don't believe a commercial enterprise will be testing their procedures or finished parts as thoroughly as they should.

https://seemanncomposites.com/ The link shows a military tank driving over a carbon fiber tank bridge. The bridge is about 55 feet long and the tank weighs over 6o tons.