TiHabanero

mstateglfr, I am simply attempting to provide an example of a seemingly intact carbon bar that was visually inspected was not intact, it was faulty after a crash, but showed zero signs of a problem existing. It may have happened 10 years ago, but that does not make it less relevant if it happened yesterday. The fact is that it happened. Sure, alum and steel fatigue, but in my experience they do not encounter catastrophic failure without warning signs the way carbon does.
My son's carbon stem broke off two weeks ago. Hopefully this is recent enough to be relevant. The bike was crashed 18 months ago, and just now the carbon steerer snapped off at the bottom of the stem. There were no visible signs of a problem, it exhibited absolutely no signs of a problem prior to breaking off.
Two months ago a customer brought a carbon bike in for work. Two months may make this less relevant, I suppose, but none the less important. Upon inspection I noticed the top tube was flexible just left of center, but was not flexible just right of center. Using a coin I tested for continuity of sound and compared it to the exact same model we had in the shop. Found out the frame had a hidden crack. I asked the customer what happened and he said that something fell on it in his garage a while ago, but he thought nothing of it. Fortunately it did not fail while riding, and that it was repairable. At some point it surely would have simply broke in two and the customer would have hit the deck.
Here's a relevant example, I hope. Two days ago a customer came in with a carbon mountain bike that had been involved in an encounter with a car. He asked that I look at the bike. Upon inspection the top tube had a fracture in it, but only showed up when I pushed down quite hard on it. Was not visible until I did that. Aluminum or steel would have shown a dent or crease at the failure point.
Got another one that is very relevant. Yesterday I replaced grips on a mountain bike that was from the 90's. Removed the barends (remember those?) and found the handlebar was creased where the barend was clamped. Turns out many years ago the rider hit a tree with the barend. A carbon bar would have cracked immediately or had a hidden fracture that would have failed in short order, and certainly would not go years without breaking off.
Do what you will, but I will never purchase any used carbon part or frame as I have seen enough examples over my 35+ years working in shops to convince me that carbon is great, but only when purchased new.
Food for further thought, this season I have encountered these 4 examples of a carbon part or frame failure, but not a single aluminum or steel part or frame failure, and there are certainly way more metal parts and frames out there than carbon.

Danhedonia

That was a rather bold post.

Juan Foote

I have purchased a used Carbon bike, it was the ride demo bike. I was able to fully inspect it and happened to work for the store selling it, so....
On that same note I would purchase used carbon accessories from a person that I knew well, perhaps rode with, along with a physical inspection of the part.
I would not order a used carbon part sight unseen.

rydabent

No---------unlike so many I am not impressed by carbon fiber.

msu2001la

Assuming I was interested in buying a carbon fiber handlebar, stem or seatpost I would be OK buying used carbon parts from a reputable shop or source like Pro's Closet, where I know someone has inspected them. I wouldn't feel any differently about this than I would buying a carbon frame bike or wheels.

I wouldn't buy a used carbon bike or parts from an unknown seller on Craigslist. In addition to undisclosed damage, I'd be worried about fakes. I'm leery buying anything on Craigslist though, so maybe not a great example.

I always find the Bike Forum community to be more concerned about carbon fiber safety than my personal experiences. I know many people (not on this forum) who have bought, ridden and raced on used carbon stuff and have had no substantial issues. I personally have crashed bikes with carbon wheels and other parts and continued to ride them post-crash (in some cases for years), again with no issues. Maybe I've just gotten lucky, but the likelihood of catastrophic carbon failures and/or hidden or undetected damage to those parts seems to be a bit overstated on the internet?

RiceAWay

In general, no. you have no idea what happened to carbon parts and delamination is generally invisible. But I have bought used CF parts and not had any trouble. Typically these parts are overbuilt to protect against voids in the manufacturing process so they are OK.

stevel610 

Nope.


https://youtu.be/NQJUSZeJE8A


https://youtu.be/j-SFAB_zK-I

Though I'm a Clyde, so I wouldn't be buying new carbon either...

billridesbikes

Would you buy these used in metal? You generally can’t tell by looking if an aluminum part is about to fail.

Helldorado

That cyclist that crashed should have known better. Who rides downhill at 45+ miles/hr on a pot-hole infested surface on carbon rims with rim brakes when you weigh 220 lbs? He was either dangerously clueless or grossly negligent.

wolfchild

Sure any material can fail...but the potential for failure is far greater with carbon than with steel or aluminium, especially with used parts or bikes. It's not worth risking a catastrophic failure just to save few grams.

TiHabanero

Oops, apologies for the bold type in my previous post. Just happened kinda thing, but being bold is OK, isn't it?

othompson

Hi, well what ois happeing here.

Sy Reene

Hi, you're new here. FYI, the proper phraseology is:
"Hi, what's this thread about?"

kingston 

I rode the Iron Porcupine 1,200k last month. 2 of the DNF's were due to carbon wheel failures, and two other riders needed to borrow replacement wheels due to carbon wheel failures. Considering there were only 34 riders, and at least half the riders were running more sensible 1200k wheelsets, that's a lot of failed carbon wheels in under 800 miles of riding.

Atlas Shrugged

A good Carbon is bad thread will never die and usually results in ever threatening stories on the unreliability of carbon. To do a 1200 k ride there usually is a number of qualifying rides usually over years where people hone their fitness, systems and most importantly equipment. I have never seen that level of carbon wheel failures In any event much less a what should be a regular but long distance ride.

kingston 

I don't necessarily have anything against carbon velopig. but I was surprised by the failure rate on that ride, which I agree should have been nothing remarkable. I rode 25 year old peter white built box-section rims with campy cup and cone hubs that have unknown thousands of km's on them and will probably last forever, so that's how I roll.

spookygeek

I would be hesitant to buying used Carbon parts but it would not always no. It would need to be something I could fully inspect ahead of use and would probably do some checks before a hard ride. Certainly would not be my first choice though.

eja_ bottecchia

Hater...