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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. |
That was a rather bold post.
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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. |
Originally Posted by Helldorado
(Post 21681275)
Would you buy a used one? Would you trust it not to be damaged (even though it might "look" fine)? |
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? |
Originally Posted by Helldorado
(Post 21681275)
Would you buy a used one? Would you trust it not to be damaged (even though it might "look" fine)? |
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... |
Originally Posted by Helldorado
(Post 21681275)
Would you buy a used one? Would you trust it not to be damaged (even though it might "look" fine)? |
Originally Posted by stevel610
(Post 21688042)
Nope.
https://youtu.be/W0iMHkYpWFo 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... |
Originally Posted by mstateglfr
(Post 21683426)
1 off examples dont prove anything as examples can show used steel and aluminum components also failing. Aluminum rims failing, aluminum bars failing, steel frames cracking, steel forks cracking, seat post clamps failing, etc etc etc.
A 1 off example from your shop that happened a decade ago is what you are using to declare no carbon parts should be purchased used? |
Oops, apologies for the bold type in my previous post. Just happened kinda thing, but being bold is OK, isn't it?
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Hi, well what ois happeing here.
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Originally Posted by othompson
(Post 21690029)
Hi, well what ois happeing here.
"Hi, what's this thread about?" |
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.
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Originally Posted by kingston
(Post 21690140)
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.
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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.
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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.
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Originally Posted by wolfchild
(Post 21681383)
I wouldn't buy anything carbon even if brand new.
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