How long does carbon fiber last?

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Hi,

Carbon fiber is known for its lightness, comfort and responsiveness. It behaves very well on the road. However, its durability seems pretty unsure, as I was told some people finally sold their carbon fiber bike because they had too bumpy roads for its use. Is it true that it breaks that easily? Did anyone among you ever experienced such situation, having a carbon frame or fork suddenly break? When buying a titanium frame, you can expect to keep it for a while, but how long can a carbon fiber frame last, considering it is impossible to avoid all the holes and bumpty roads?

I currently own a Gary Fisher Procaliber mountain bike - it has the original OCLV frame similar to the one on lance's trek. I got it second hand just over a year ago now and had the same concerns as you.

I didn't find any conclusive answers, but looking at other forums everyone either said their frames were still going strong after years of thrashing or had broken within months. I came to the assumption that the durability of these frames was a bit digital - either lasting weeks or lifetimes.

Since my bike was about 7 years old when i got it, i reckon it's one of the ones that'll last a lifetime, so i've been giving it a thrashing off road this last year with no problems - it does have front suspension though which you won't get on the road bike.

I'm no materials expert, but i'm guessing the inconsistent durability of these frames was down to the manufacturing process causing some frames to have either a high stress or a weak point. I assume any problems in this area have been sorted by now.

Rich



Originally posted by devinci_freak
Hi,

Carbon fiber is known for its lightness, comfort and responsiveness. It behaves very well on the road. However, its durability seems pretty unsure, as I was told some people finally sold their carbon fiber bike because they had too bumpy roads for its use. Is it true that it breaks that easily? Did anyone among you ever experienced such situation, having a carbon frame or fork suddenly break? When buying a titanium frame, you can expect to keep it for a while, but how long can a carbon fiber frame last, considering it is impossible to avoid all the holes and bumpty roads?

devinci-freak,

I can't imagine who would think a road could be too bumpy for a carbon frame to handle it - that's just dumb!

I have an 8-yr old Kestrel 200sci. I just rebuilt it with all new drivetrain, saddle, pedals, etc - which all wore out - but the frame is fine. It takes plenty of abuse on harsh roads, but that is why I love it - carbon has excellent vibration damping qualities while still allowing the 'feel' of the road.

Go with carbon man, you will love it!

One of my road bikes is a carbon fiber Time Helix HM. I got it in 98 and have about 21,000+ miles on it. I wore out the pawls in the Rolf Vector Pros already but no problems with the frame. I love the feel of the bike. Go for a carbon if that's what you want. I agree with Bug Man, that's silly thinking a road is to bumpy for cabon fiber.

Good carbon fiber could very well outlast you.

Bugman -- sweet pic for you avatar. Nice!

Thank you for your answers. However, would it be possible to explain how you used those bikes and what makes you think it would be stupid to think carbon isn't strong enough for very bumpty roads? I'd like to recall the little elongation capacity that material has.

The secret to carbon is directional layering during frame construction. Layering the fibers in one direction gives you stiffness, while layering in the opposite orientation results in flex. The stiffness can be taylored by adjusting the orientation of the multiple layers relative to each other in different parts of the frame. Typically, the layers are oriented to create a frame that is vertically compliant (for comfort) but laterally stiff (for efficient power transfer to the pedals).

I prefer smooth asphalt, of course, but I've ridden on more than my share of rough pavement - you just gotta go where the road takes you if you want to get the miles. Honestly, even on the roughest roads I worry more about my wheels and tires than I do about my frame.

Relax - whoever told you carbon can't take rough roads is an idiot!

I had a carbon tube take a direct hit from a car bumper in 1989 and I still ride that bike from time to time. That tube held up much better than my wheels and fork.

A friend has a Trek 5500 carbon fiber that now has 25000 miles on it.

I think if the bike is built properly then the road surface will do little to damage the frame any more than what would happen with steel or Ti.