doctorSpoc

I was with you when you were simply stating that you need to inspect and give care to carbon parts differently than metal/steel but you are taking it a little far now...

even aluminum over time fails like carbon does too... i've been around long enough to see two seat posts that looked just fine break suddendly as well as a handle bar and last summer an aluminum crank crack just above the pedal and fall off... we had to push the guy for 30 clicks

the other difference is that it takes 3 to 5 times more force to get the carbon to break than it does to get the steel to bend out of shape and since the steel is likely built with a 3x safety factor you are likely not going to get the cabon to break unless something really, really, REALLY bad happens..


everyone knows (should know at least) that carbon has all of it's strength along the fiber, so if you are stessing it perpendicular to the fibers as you would be when clamping it, it has almost no strength so it is easy to crush it (and set yourself up for a catastrophic but easliy forseen failure down the road) unless you use a torque wrench etc. etc. just as carbon parts manufactures say you should... part of the special care, but when installed properly and subjected to the stresses it was intended it will perform as intended... this really has nothing to do with carbon spontaneously self destructing... you are talking here about improper installation.. but irregardless of material improper installation will likely lead to failures... i agree that carbon does requires special care... it's not steel.. but it doesn't just blow it self to bit just because it's Tuesday and Venus is aligned with Pluto.

[Edit]will give you this... it is WAY easier to over torque a carbon seatpost or bars than it is for metal seat post or bars, i.e. get the installation wrong.. that's is one of the bad things about carbon... no strength perpendicular to the fibers[Edit]

slvoid

Sorry, I choose to buy titanium, could've had a cheap carbon bike for LESS.
Don't get your aluminium bike near mercury either!

spacefuzz

Hahaha. I have taken graduate level strength of materials classes and destroyed composites in the lab, its fun. And this thread makes me laugh. I want to know where people got the idea to treat carbon fiber like their grandmothers china. Like doctorspoc said just install it right. And if you know what to look for the odds of "spontanious & catastrophic failure" are small.
Also from an engineering standpoint if you impact carbon and it breaks, and you impact steel and it bends, they are both termed as failures of the material. when the steel bends it means that the max stress went past the yeild for the material and plastic deformation takes place. This significantly weakens the material, yup you may be able to ride it for a bit more, but not safely. Whoever made the comment about the imploding fork, thats funny.

hiracer

Joyce was wearing a helmet per a newspaper article cited in this thread.

hiracer

Haha. Not funny when there is a nonvisible manufacturing defect in YOUR fork. Or when you buy a used, crash compromised fork.

Old engineering saying: In theory there is no difference between practice and theory. In practice there is.

Bottom line: Carbon is stiff, light, and tough. And it has a dangerous failure mode for bicycles. You can ignore the failure mode only on the assumption that it will not fail. The vast majority of the time, that assumption is valid. Once in a great while, it's not.

spacefuzz

I never said ignore the failure mode, I said you can sometimes avert failure if you know what your looking for and inspect your bike. I have personally crashed my carbon fork, twice. And both times I brought it in to the trek dealer and also went over every inch of it myself. I still trust it.

And whats funny about an imploding fork is that an implosion implies things getting sucked/crushed inwards, if a carbon fork were to shatter, it would technically explode. Relax all of the carbon bikes arent going to randomly self destruct.

hiracer

Of course you are right from an engineering perspective. But a little literary license never killed anybody. "Imploding" invokes a much more vivid mental image.

spacefuzz

dont forget the carbon fiber shrapnal that impales the innocent bystandars.

hiracer

Just to close the circle and maybe this thread, I do believe Trek screwed up and completely forgot to mention any warning about that shrapnel. Somebody should email them. They need better lawyers.

NickExxon

I couldn't find it at first, either. Turns out it's stuck to the back of page 2. As an aside, is anyone going to afix this decal to the top tube as per the instructions? Sort of dorks up the paint scheme for me.

Regardless, I inspect my bike prior to every ride.

2l8

man now i'm terrified.
here i am deciding on whether to go with a giant tcr2, a specialized roubaix expert, or a trek 5200 for my FIRST BIKE.

now i'm terrified the whole carbon bike will shatter underneath me and i'll be impaled on my frame or worse it'll fail while im going 30+ mph and i'll fly head first into the pavement never to be able to walk again.

how concerned should i be since i am considering a carbon frame as my first bike?

bmike

Bikes are typically ridden, not crashed on a daily basis.
I would not worry. If you have a wreck, drop, or scratch, take it to your LBS for an inspection.

If you plan on beating the bike with a chain, knocking it over on an hourly basis, running into things, hopping off every single curb, cliff, or drop you find, taking it to the BMX park, getting big air, etc.... carbon may not be for you.

ElJamoquio

I hear Trek is making lots of money now. Can I be an innocent bystander? Anyone care to be a paid witness?

catatonic

Good call Alan.

I usually don't agree with many of your posts, but this one I definately agree on.

Composites are not something to just put blind faith into. I retired a fork that might have seen 3 years more service, just out of a safety concern...namely the resin top layer around the bonding point of the CF legs to the alloy crown had a very fine stress mark in it...just enough to give that section of resin a slight haze...polishing didn't get it out...so replacing it was the safe thing to do. For me my bike is not a toy...it's my primary transportation...so I can't afford to take risks like that.

Plus hospitals suck

Cayman

Hey let's leave all the lawyers alone . If Carbon failure is a real possibility be glad that the lawyers advised Trek, and others to give these warnings so that we as consumers can make an educated selection of equipment. Or do those that want to deny the possible dangers want to blindly choose their equipment? I'd rather be as informed as possible, it's the same reason all medicines have so many warnings. Not to scare people, just to give as much info as possible...

Vinokurtov

Alan, your initial post was spot on and good advice for riders of ANY material bike (If you crash, check things carefully).

I have not been able to get in touch with Iban Mayo to have him run over my steel bike going 18 MPH, so I can't say if a steel chain stay would snap under similar circumstances. My guess would be if a 140 pound rider rode over a lightweight steel bike at this speed, there might be some damage. And if someone ran you over at that speed, or ran you over at all, I'm somewhat skeptical you'd refer to it as "minor".

I also would note that Mr. Armstrong finished the stage and in fact, won, with a broken chainstay. And I recall that one rider had his steel forks snap during a TDF stage, one of many steel failures in that race over the years. And in my younger days I broke at least a dozen frames, all of which were steel.

Don't dilute an excellent point with revisionist history or by assigning claims of super durability to a particular material.

wagathon

I consider a pedal spindle to be about as beefy as components get. Nevertheless, I was on a ride when a Canadian physical therapy major snapped one off at the crank arm. He hitched a ride to the closest town, which was a small place, and told the first kid he saw that he'd buy a new peddle. When we rode through town, he was surrounded by about five kids on bmx-type bikes, each with an assortment of pedals. My guess is that 20 or more bikes in that town were probably short one pedal that day.