How sturdy is carbon?
 

Thinking of buying a Roubaix comp but DH says it must be handled delicately or else the carbon can break (ie. from a side impact). If the bike is knocked down on rocks or pavement, or hits my car when it's on a bike rack, is the frame likely to break? Or is this possible? I'm not extremely rough on bikes but not the most delicate either. Sometimes I'm a bit klutzky. Also - any thoughts on the Roubaix comp 06?

One reason (the link) why I chose Scott CF over the others. But is shows how strong carbon actually is.

October 22, 2004
SCOTT CR1 tops the charts in the latest EFBe fatigue test

A recent test performed by EFBe (Engineering for Bikes), an independent test facility in Germany, proved that the SCOTT CR1 is the benchmark carbon road frame. Awards were given in three categories at the conclusion of the performance rating test. The test starts by applying an “out of saddle load” to measure fatigue life and then considers frame weight to categorize each frame. The CR1 was rated number one in EFBe’s “Top Performance” category, comprised of the best top quality construction frames.




The SCOTT CR1 not only achieved the “TP” rating but was also the lightest frame tested, giving it the top spot in the results. “The less a frame weighs and the higher its performance category, the more perfect its construction!” explains Manfred Otto of EFBe. “Statistics show that only 40 percent of all EFBe tests are passed, so to own the top spot in our test is a real honor.”

Check out the results for yourself at: http://www.efbe.de/erenn.htm

As long as it doesn't sustain any direct hard hits on say, a big rock....you should be fine. I don't know how Specialized is, but I know Trek has a crash replacement policy if you kill your carbon frame.

I'm not a huge fan of carbon... any deeper scratch that goes through that plasticky outer layer compromises the integrity of the frame. I can't feel good about a material that is so sensitive that Trek has to put warning labels on all their bicycles equipperod with carbon forks saying "WARNING! This bicycle is equipped with a carbon fiber fork. Any crash or damage compromises the integrity of this fork, and may cause it to fail unexpectedly. Please see your dealer or contact Trek immediately for replacement." (paraphrase) Also, our shop just recieved our giant posters from Trek that essentially say the same thing... its hard to sell customers a carbon bike when you have giant posters say "you may die if you ride this bike", and hard for me to feel 100% confident in the carbon fork on my Cannondale. Theres no doubt carbon is much more sensitive and mysterious in terms of handling, care and damage than steel or aluminum alloys.

Trek would be better off with a sign saying "You will not have a cool bike if you ride a TreK".

:rolleyes:

almost 100% of decent road bikes have CF forks, even the steel ones. no one's died yet.

Carbon itself is very sturdy. It is a very strong element. In fact, it's known for its strength :)

How strong is it in bicycle usage? Well, there's definitely reports of things cracking and getting chipped and whatnot. Remember that a lot of carbon gear on bikes is designed to be as light as possible, so they're pushing the limits of how strong it needs to be. A carbon frame should be able to handle just about anything you throw at it. Certainly you can chip the finish, and maybe some of the layers... but that will take some doing. You're likely to ding your aluminum or steel frame with less effort. Yes, metal frames can theoretically be repaired.... but if you have that much damage it's probably time to buy new components anyway.

I know this, and yes, people have died when the leg of their fork has snapped off. Thats the reason Trek has issued the stickers/posters, was because someone bought a OCLV and had his fork break on a descent, resulting in his death. I personally have seen probably 10-15 carbon forks missing a leg in the past 5 years, from various accidents, crashes, whatever. Steel or aluminum forks missing a leg? Never seen one. Seen a few bent, never one broken. Bear this in mind: the ONLY way carbon fails is catastrophically. It doesn't bend or deform, it only snaps.

You been well indoctrinated, and fed lots of BF BS stories, and 10-15, well, that just isn't true. If anything you said was really true, Trek would be sued out of business, as well as every other bike maker.
Putting a disclaimer on a product does not protect you from lawsuits.
Take a look, every major manufacturer has switched to CF forks.
I have hundreds of hours of pro race DVDs, with only two snapped forks from 50mph+crashes, that would be bent to useless if they were steel.
Check consumer recalls for the late 90s-several steel forks were recalled for snapping welds.

What Koolaid have you been drinking? FYI ... I was riding my trainer the other night, got out of the saddle to stretch my legs a bit, hands on the hoods and my stem - which is all alu - snapped right at the front plate underneath the bolts. No bending or deforming there - just a stright out snap. Went arse over tit on a damn trainer ...

Actually, if you are rough on your bike, I would avoid the Scott CR1, and also the Specialized Tarmac.

While very strong in the German test which measures repetetive cycling loads, they acheive their light weight by using a large diameter shaped tube that varies in thickness. The center of the tubes are relatively thin and more susceptible to being puntured. Most shops that sell the CR1 frames have a cutaway that shows the varying wall thickness.

Personally, I ride the TCR Comp because I tend to be rough on my frames. While not the lightest CF frame on the market it does use a smaller diameter carbon tube with a more constant wall thickness that is less likely to sustain puncture damage. Just something to keep in mind.

I also just went through buying my first carbon bike, me coming from MTB frames the carbon frame just felt so fragile and wasn't too sure, don't know but did you read this article? It explain a little about producing the Specialized carbon frame.

here is the article
http://www.specialized.com/bc/SBCBkM...vctp8em.j27002

Click on : Taking The Witchcraft Out Of Advanced Composite Bicycle Frames

I also don't know if you do any mt. biking, or know how much abuse mt bikes takes, but yes they also use carbon for mt. bikes frames and its very strong.

buy the roubaix. Carbon fiber is as strong or stronger than any metal used in frames today. Carbon fiber composites are very complex materials and damage can be within the composite and not visible so after any serious crash it sould be inspected as should all bikes since damage can occur ,at welds, in metal frames and also not be visible. normal bumps on the car rack or falling over at the bike stand is not a real concern. Warning posters/labels are a neccessity in the lawsuit happy US of A just like warning labels on hot cups are a fact of life. Since carbon fiber is high in tensile strengh as well as compressive it actually absorbs a lot of the shock than can fatigue metal frames. but if you have a serious crash take it in to be looked at. next time you fly in a boeing 777 or watch the spaceship one fly these airframes are made of very similar carbon composites that are on your new Roubaix.

Yep, just like aluminum.

Here we go again.

Can't we make one of these threads sticky. This comes up like every 2 weeks.

You will get replies all the way from

1. RUN AWAY FROM CARBON. THEY WILL ALL KILL YOU WITHOUT WARNING.

to

2. I BEAT THE LIVING @#)(&# OUTTA MY CARBON ROAD BIKE AND CARBON MTN BIKE AND IT STILL RUNS GREAT.

And pretty much everywhere in between.

-D

Nope, aluminum bends. It snaps more easily than steel, but trust me it bends. Ever bent back a derailleur hanger? They are aluminum. In fact, I have bent the spiders back on a few aluminum cranks in a pinch. I also straightened an aluminum crankarm. Does it compromise the inegrity? Yep, but, point is, aluminum does bend before it just snaps.

There is so much BS in this thread, its sick. I have people saying that I feed into BF's BS, which is really funny, because if I did I would be riding a Scattante full carbon bike or an OCLV. As for the 10-15 forks, hey, I spend 20-50hrs a week at a bike shop, and have for the past 5 years in two states, plus I race collegiate and used to race USCF, so guess what? I've seen a few broken forks, which like I said were the result of various accidents, and whatnot. Some people got their front wheel in a sewer grate, some went into a curb at a crit, some got hit by a car, etc... my point being that carbon SNAPS, it doesn't BEND.

Did I ever say that no aluminum/steel fork in the history of the world has broken? No. I just said *I* (do you people even understand what a personal pronoun is?) have never seen one. I know Vitus aluminum forks were recalled, because of a manufacturer's flaw (being that they were glued together + seperating)... thats a little different... I can't think of a fork being recalled because the metal would just snap on impact, or because if it got a nick in it, it would compromise the integrity of the fork.

For the record, I have have had 3 bikes with carbon forks I have liked very much. However, I know the history of the forks and trust me, the first time I crash on one it will be gone over very, very thoroughly and if I feel the crash was severe enough to warrant it, it will be replaced immediately, even if there is no outward appearance of damage.

this should be done for every part, genius. carbon bends, flexes and deflects-that's why its used for forks.

Carbon fibre in mountain bikes?!?!?! Surely you jest. Never has my flabber been so ghasted! :D

Hey khuon, didn't know how new is the newbie :)
Nice K2 btw

Quite frankly this is the key issue with CF.

CF is strong. It does flex (as others have said, why else have they touted CF forks on an alu frame?).

There is a reason CF bikes have disclaimers on them and such. NOT that they are more dangerous and more fragile.

Simply that unlike most metals, (which USUALLY will show signs of impending failure, hairline cracks, dents, etc) CF can often look completely normal after a crash and yet be damaged to the point of failure.

-D

I once had a pair of aluminum handlebars break suddenly, and without any warning that I noticed. I was lucky: I fell away from traffic, and ended up with just three stitches in my knee. A friend of mine has also broken a pair of aluminum handlebars suddenly. Another friend has broken an aluminum stem. All of these cases resulted in sudden crashes without any warning. Does this mean that everyone should stop riding aluminum frames and components? I'd say no, it means that everyone should be careful when installing components, and inspect them regularly for damage, especially if they are racing and have crashed.


There's a huge difference between failure that results from a crash, and failure that causes a crash. Many carbon fiber bashers point to damage resulting from a crash as evidence that carbon fiber is dangerous. Whether my fork bends or breaks after my wheel gets caught in a storm grate is of little consolation: after doing an endo and a face plant, I'm going to have a very bad day either way.

If you crash your bike hard enough, parts (or even the whole bike) will have to be replaced whether they bend or break. I'm worried about a novice mechanic (and I do not mean seely) who bends something back in place and thinks it's perfectly fine*. I've ridden steel, aluminum, ti, and carbon bikes over the last 20 years. Guess what: I've had aluminum parts snap off, a friend broke a ti frame with regular use, and the only frame that I ever cracked was steel... so bikes need to be inspected regularly, whether they're carbon or some other material.

(*edit: The comment regarding being worried about bending something back into place is referring primarily to aluminum that was seriously bent to begin with. There are instances where bending a frame or part back to its original shape is no big deal.)