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regarding carbon fiber durability(10 posts)

regarding carbon fiber durabilityDuane Gran
Aug 10, 2001 9:29 AM
As of late there have been several requests on this board for feedback on various bikes, including ones of carbon fiber construction. Invariably, someone points out that this material isn't as durable as (insert other material here). I'll confess that I'm a fan of carbon materials, so I'll get that bias out of the way up front. I did find an interesting site where the author made a good attempt to actually break his bike and was very pleased with the durability of carbon:

http://www.chainreactionbicycles.com/carblife.htm

I hope you also find it useful or helpful. Maybe I'm just throwing petro on the fire, but it looked like we needed a little counter balance to what seems to be some off-the-cuff remarks about the durability of carbon fiber.
Here's another linkAndy
Aug 10, 2001 9:45 AM
http://www.efbe.de/erenn.htm
re: regarding carbon fiber durabilityLC
Aug 10, 2001 10:34 AM
You have to be careful that you are not compairing a cheap old CF bike with aluminum joints to a new top end monocoque frame; there are major differences. a good CF frame will never break from just pedaling because it does not have a fatigue limit like a metal. The only real downfall to CF is that chain drop or fall that scapes into the actual fibers can weaken the frame.

I have two CF bikes and a steel and a aluminum bike and now I find I only ride the non-CF bikes if I have to. I really don't want to feel the road anymore than I have to.
CF durability under normal condition isn't the issueSlothlike
Aug 10, 2001 12:19 PM
it is the unwanted and sometimes inevitalble crash or scraping of the frames surface that is a concern. Like LC mentioned that is a possibility if the outer surface is broken by a scraped or chain and the fibers are essentially frayed, that will/can lead to frame failure. On the Treks, I am positive I read that the deraileur hangers are not replaceable, so if it is banged in a crash or in transport, you need a new bike. To me that was enough for me to go titanium. CF under normal riding conditions is fine, but for those of us that keep our bikes a long time, CF has more durability concerns. Titanium is the most durable of all the frame materials. I enjoy steel but they rust eventually. Aluminum wouldn't be so bad if it wasn't so harsh regardless of what people say about high end aluminum, it camparison to ti or cf it is harsh. I would love a CF bike, but the concerns that I stated worry me when I am about to spend 3-4 grand on a bike.
Regards
GLG
OCLV hangersRusty Coggs
Aug 10, 2001 1:00 PM
....can be replaced by Trek at the factory. If one hasn't been there check the tech articles at www.chainreactionbicycles.com on CF durability.
Hanger Replacement Cost = $70grzy mnky
Aug 10, 2001 1:05 PM
The frames are WAY crash worthy - based on personal experience. just go through a Trek dealer.
CF durability under normal condition isn't the issueLC
Aug 10, 2001 3:47 PM
In a crash anything can get broken or bent no mater what the material. I would rather enjoy a CF frame now and then worry later what to do after the crash. At least if I crash it will probally be my fault, and not a tube that reached its fatigue life, interior rusting, or a joint that was not quite properly welded. If there is something wrong with my Look 386 frame like a big gash and cut fibers, at least I will see it before I even swing your leg over it.

I don't own a Trek because I don't want any joints, but there is an advantage to this design too. I understand that you can have a tube replaced fairly easy at the Trek factory. They heat the joint, which melts the glue and then they slip new tube on. The downside is that you still have joints that can come unglued, but it is usually not as catastophic as a weld or tube failing.

Even if you did ruin a whole frame, you can still get a new frame and that does not cost 3-4 grand. After 5-10 years I may even get a new frame just for the hell of it because there will be advances in technology. Seems like every year they cut some more weight and make those CF frames stronger. If you spend a fortune on a titanium bike then you may be stuck with that 3.2 pound frame longer than you even enjoy it, and if you do ever need repairs on a titanium frame, that will cost a bunch too.
Good insight......Rusty Coggs
Aug 10, 2001 5:02 PM
...on a subject that often generates more hype and BS than useful facts. I have an OCLV. It may not be my favorite ride,or a bike I would consider my one and only but it has it's place, and it's durability isn't an issue, at least in my mind.
CF durability under normal condition isn't the issueSlothlike
Aug 10, 2001 9:37 PM
You make many valid points and I am not saying CF is a weaker frame but it is more delicate than titanium because of the inherent material which is woven fibers. As far as a 3.2lb ti frame. My ti bike is 17.5 lbs with pedals in a 57cm which is pretty light considering my own weight. The 2001 5200 Trek (58cm which is really a 56cm) weighed in at 17.5 pounds without pedals in Bicycling magazine. So I don't see where the big weight savings over ti is? It is a good value though for a nice CF frame. Getting gashes in a frame is more common than it seems. A simple bad shift allowing the chain to slip off and gets wedged between the chain stay and small chain ring happens and took a nice chunk out of the paint on my steel frame. That could be a real problem with CF. The new 5900 Trek is 16.1 lbs without pedals but it is ridiculously expensive. Just food for thought when considering any bike purchase. Titanium seems the most bulletproof assuming there are no weld flaws. If a ti frame doesn't crack at the welds within the first month, it will probably last forever.
Dropped chain on OCLVRusty Coggs
Aug 11, 2001 5:37 AM
My OCLV came with a thin stainless guard attached to the stay with double sticky tape as protection??? from such mishaps. Don't know how effective it might me as I have never dropped a chain.Although it seems to be a problm for some. My used Carrera came with a bad case of chain rash to the paint on the right stay which did not penetrate the chrome plating, so it must happen.It could possibly get pretty ugly with some aluminum too.