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Discussion Starter · #1 ·
a pun from the movie "Christmas Story" I have always loved that movie :) I want to hear from OWNERS of CF frames and what your experience has been. I know, Iknow, Steel is Real and Ti is Fly, Aluminum is, well aluminum (cant find a rhyme) I have a CF frame that I recently crashed, frame got cracked near the BB making it history, my fault. Now this frame is a 2006 model, and is one of those uber light jobs, around 1000 grams. What I am trying to come to grips with is this... are these "super light" CF frames really too fragile for everyday use/ abuse, I mean is that the trade off for the lightness we lust for, too fragile or did I just have some bad luck and need to give it another go?:thumbsup:
 

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I just got a new carbon fiber blade for my hockey stick. It's supposed to be stronger and more durable than the wood ones.

I know it's a different animal, but it shows that carbon can be very strong.
 

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Rondo said:
a pun from the movie "Christmas Story" I have always loved that movie :) I want to hear from OWNERS of CF frames and what your experience has been. I know, Iknow, Steel is Real and Ti is Fly, Aluminum is, well aluminum (cant find a rhyme) I have a CF frame that I recently crashed, frame got cracked near the BB making it history, my fault. Now this frame is a 2006 model, and is one of those uber light jobs, around 1000 grams. What I am trying to come to grips with is this... are these "super light" CF frames really too fragile for everyday use/ abuse, I mean is that the trade off for the lightness we lust for, too fragile or did I just have some bad luck and need to give it another go?:thumbsup:

So you crashed it and destroyed it and are wondering if it's the material's fault?

Any frame, made from any material, can be destroyed in a crash.

I've put 7000+ miles on my carbon bike in the past year and it's the same today as the day I built it...
 

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Discussion Starter · #5 ·
Sounds stupid, I know

backinthesaddle said:
So you crashed it and destroyed it and are wondering if it's the material's fault?

Any frame, made from any material, can be destroyed in a crash.

I've put 7000+ miles on my carbon bike in the past year and it's the same today as the day I built it...
I did crash but the circumstances were more of a tip over than crash which is the reason for my fragile question.
 

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Yes.

I've read two other posts about people who had their bike tip over while leaning against the wall. Poof. Frame gone. (cash register noises). Lots of posts about cracking handlebars, tubes, forks due to excessive clamping pressure.

I think it is a combination of the complex design properties, designers being lower on the learning curve with material designs, and the quest for light weight which lowers a factor of safety and will affect frames of any material.

It's true CF can be incredibly strong depending on how it is designed, made, and the application. My biggest concern with cf for bikes is how to determine when it is damaged and how it might fail (fast or slow).

I wish I could find the picture of the ocean racing boat made of cf that snapped in half because someone ran a line to a winch in a way the designers didn't consider in their analysis.
 

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Rondo said:
What I am trying to come to grips with is this... are these "super light" CF frames really too fragile for everyday use/ abuse, I mean is that the trade off for the lightness we lust for, too fragile...:thumbsup:

Yes.




nmnmnmnmnmnmn
 

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Depends on the design.

Some makers opt for a large diameter tubing which allows for a thinner CF tube wall (Scott,Cervelo, etc.), others have gone with a more standard appearing diameter for their tubes with a thicker CF tube wall (Look, Giant, Time). While riding both designs are equally stiff and make for excellent bikes, I always wonder about how the two different design approaches stand up to abuse.

Personally, knowing how poorly I treat my equipment have always opted for the latter design approach. I worried that the thinner tube walls are to easy to accidentally puncture when being mistreated or to crack when subject to forces not normally encountered while riding, like those encountered duing a crash. As a result two current frames are the Giant TCR Composite and the Look 585.

I don't think carbon is fragile, in fact I am currently using full carbon clincher wheels, carbon bars, carbon stem, carbon cranks and a carbon seatpost and have had only one issue when I overtightened my stem and crushed the bars.
 

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As ewitz said, it's the design.

One of the attractive things about carbon fiber is how relatively easy it is to make it strong where it needs to be and remove material where it's not needed. In this sense, a carbon fiber frame is "heavy" in the stressed areas, "extremely light" in the non-stressed ones. Because of this, most stresses other than those induced by someone actually riding the bike can be removed to some degree from the design equation. That makes a carbon fiber framé (pronounced frah-may) extremely strong as it pounds over the roads, but a bit fragile when subjected to non-riding stresses.

A good analogy is a competitve rowing shell. These boats are strong enough to withstand the forces of eight powerful rowers exerting huge forces on their hulls. But drift one of these shells sideways into a bridge pylon at a leisurely two knots and there's a good chance that the shell will crack right in half and sink.
 

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Discussion Starter · #10 ·
Thanks Guy's

I have yet to hear from the rep but there is a possibility I may get a discount on a replacement frame. Although the frame is only 6 months old they are under no obligation to offer me anything so I am eager to learn of their decision. Either way I need another bike/ frame and right now I am second guessing my decision buying a super light carbon frame. Hind sight is always 20/20 :rolleyes:
 

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It is about design. Carbon fiber can be used to build a bomb proof bike. It is used to build the tubs on the cars that Indy and F1 drivers survive crashes in. However in the bike world it is designed and used to build a reasonably strong very lightweight bike. That is what the market has asked for. Lighter and lighter and lighter. If all the technology going into a 2lb. carbon frame was used to make a 3lb. frame it could very well be more durable than a 3lb. steel or ti frame. People tend to fall into groups in the bike world though. You either care about weight and speed and closely count grams or kinda don't. I say kinda because I don't want a 25 lb roadbike but 20-22 with traditional wheels, pedals, cages and a spare tube and air on the bike is what I like. I don't need sub 17. That is what carbon has been used to achieve.
 

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Rondo said:
I did crash but the circumstances were more of a tip over than crash which is the reason for my fragile question.
A tip over and a crash are two different animals. My Ridley has been knocked over a few times in the house and is no worse for wear. It's possible that the frame was already broken and your shunt was the straw that broke it. If the damage looks like a break and there's no marks from an impact, I'd try to get it covered under warranty. If there's a big chunk missing where it struck something, I'd tell you that you're SOL.

There is also a big difference between just falling over and falling into a hard object. Sure, if it hit a cinder block when it fell, it might cause some damage, but just falling over, I doubt it.

As for the comment about broken carbon because of clamping forces...:rolleyes: If you break your frame by either installing a part incorrectly or clamping it in the workstand, that's your fault and no one should feel bad for you. Poor mechanic skills are not covered under warranty.
 

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Rondo said:
I have yet to hear from the rep but there is a possibility I may get a discount on a replacement frame. Although the frame is only 6 months old they are under no obligation to offer me anything so I am eager to learn of their decision. Either way I need another bike/ frame and right now I am second guessing my decision buying a super light carbon frame. Hind sight is always 20/20 :rolleyes:
Get one of these :

http://www.surlybikes.com/pacer.html

http://www.surlybikes.com/longhaul.html

And you will never have to second guess yourself again.
 

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And yet there are thousands of professionals putting millions of miles on the latest/greatest CF frames available, treating them with utter contempt and putting far more stress on them than any of us would ever consider.

And doing it and winning races and being successful.

In addition to that, there are many dozens of these bikes on these forums and I think I've seen perhaps one or two cases of "I dropped my bike" that resulted in damage. I've seen exactly 1 photo of a Parlee that was broken in a crash during my entire 10 years hanging out in this forum.

There's a high likelihood it you tipped over your aluminum frame it would be ruined too. Steel and ti might weather a big dent in the top tube, although I wouldn't be inclined to ride it.

All that remains is that you have a camp of people that always answer "yes" when asked if CF is too fragile/dangerous/breakable/explosive. I think the evidence in the marketplace suggests otherwise.

I know I'm not worried about the 3 I own.
 

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odd arguments

I agree 100% as to the design and application issue.

Anybody here recall the Ti spoke joke? IMO, at least, there was a piss poor application fora material.

However, the issue here seems to be, well, what if I crash and how do I know the bike is OK. If your bike is designed well, a bad crash will potentially ruin any frame. Bad crash here defined as a wipe out your skin on the pavement, you hit a rock, car person another bike etc etc etc etc I woukld bet that any bike of any material would not get out of that unscathed. Yes, that would include Ti.

BUT folks here are also pointing out that super high end racing machines may have more issues. Well, yes, they do. A super high end super light anything will have higher care and maintenance issues. REGARDLESS of the mterial. Again, a good design does not mean an indestructrable machine IN THIS CONTEXT. If you want a super light machine etc etc be prepared to have issues that go along with it.

I dont get why folks who blow 5+ grand on a high end feather light bike AND dont get that hey, you might want to consider that if its a super light climbing missle, it just may be a bit more fragile. In fact, it will be.

This is not unrelated to the brainiacs who buy the Ferrari and then lo and behold, dont change the oil for over 10 thousand miles, drive it like a rented pack mule and then gasp, its new car time........Yeah, it would be since the car is designed to go super fast, go super hot etc etc A higher end car does not mean, well, I wont have those pesky issues I had with the POS I used to drive.Thats right, now you have even more pesky issues.:thumbsup:
 

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not just design....

the idea that it is mainly dependent on design is too big an oversimplification. Material sciences clearly demonstrate that carbon fiber, and particularly carbon nanotubes, are vastly stronger in terms of their ultimate strength. Combined with the fact that carbon's density is substantially less (a lot less), demonstrates from a materials science perspective that carbon is vastly stronger and lighter than steel. Of the order of 62000MPa vs. 1860MPa... Steel is not as brittle as carbon fiber, so differs in terms of yield strength (will deform to a certain extent without damage), yet there is no question that CF is vastly superior to steel. The fact that it is not isoptropic further means that CF layup can be optimized to create patterns of strength/compliance that again cannot be accomplished with steel.

The fact that the lightest bike in the pro peloton (R3) also won Paris-Roubaix illustrates pretty clearly what can be done with CF and good design...
 
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