Glyndwr

Nitto? How about a Cinelli or 3T quill stem? Even better!

Ed333

The question as posed, with reference to years owned, triggered another question : Assuming hard regular use, do carbon fiber frames have a safe useful life span (one short enough that anyone now living might want to know about? Newbie question...big and heavy....wondering about used CF bikes....

zacster

Mine is 15 years old and I don't see anything wrong with it. There were people who claimed back then that they wouldn't last, and they certainly wouldn't survive even a minor crash or just falling to the ground. Meanwhile, airplane wings are made of CF. I think those get a lot more stress than bicycles. The main thing is that CF doesn't bend, so if it does crash hard there is a chance of cracking the frame.

I was doing a century ride in the fall, and at one point on a less than great road surface, a bunch of jerks come barreling by us. Well, one of them then hit a sewer and went down, taking down all his friends. I managed to come to a stop even though I was right behind them at that point but at least I was going slower. My partner of the day was a few lengths behind me and was amazed I stayed upright. After I checked out my bike and we made sure the guys that went down were OK, one of them is looking at his brand new bike. He cracked the frame! Since they were OK I didn't feel too sorry for him because what they did was totally ridiculous weaving through the more casual riders at that speed, at a point with a crappy road.

upthywazzoo 

Carbon fiber is super stable. Provided that the fibers and epoxy stay intact, a carbon frame would outlast a steel or aluminum frame easily. The mtbf of carbon fiber is insane. The epoxy that holds it together will break down under UV light, but paint and clear coat inhibit that kind of radiation. Carbon fiber is so stable in fact, that throwing carbon frames away is a problem, since they won't degrade.

supernova87a

So is there something, or nothing, to the idea some suggested above the a 20 year old carbon frame will have "worn out its smooth-riding life" and be a harsher ride now (as I interpreted the idea to mean)? Or are people conflating with the more modern build techniques of a newer carbon frame?

thehammerdog

throw some new paint on it.
strip down clean up groupo new cables professionally paint and Bam....new bike. that will scratch the itch for new.
unless as someone said u have the $$ to spend. then get new.

upthywazzoo 

I am not in the carbon fiber manufacturing industry, but I've read a lot about its manufacture which has some similarities to an industry I'm in (PCB manufacturing)--so take this with a grain of salt

Let's just answer your question first--if a 20-year old carbon frame was indeed fatigued--it would feel more compliant (lose stiffness). I think you are correct in that the new monocoque carbon layup techniques of today are being compared with the "let's just roll it up into a tube and bond it with huge aluminum lugs" of yesterday. If an old lugged carbon frame is really degraded--yeah it's not gonna ride super great, because honestly it probably wasn't all that great to begin with.

A ferrous metal like steel has a fatigue limit. When subjected to stresses under this limit, steel can remain intact "forever". There are a limited number of cycles over this limit that steel can endure before it fails. Carbon fiber has a "quasi-fatigue limit" in that there is a level of stress at which the inherent microcracks and voids don't propagate, but beyond that it's up in the air. For this reason, when carbon fiber is used in an aerospace application, it's generally overbuilt (as it should be). By using much more carbon fiber than necessary for the load in question--the likelihood of failure goes way down.

This differs from the cycling industry, of course--which will use the minimum amount of material necessary for the load because that is what makes lighter bikes. This also puts a large responsibility on that of the manufacturer to produce a layup with as few flaws as possible. The less material you have, the more the flaws are magnified. I should also clarify my earlier statement in that carbon would far outlast steel/aluminum. This is not because of the inherent durability of carbon, but because of its corrosion resistance. I think if both a carbon and steel frame were kept in a climate controlled storage area, then they'd both last indefinitely.

WhyFi

Compromised structural integrity because of crashing, etc would be more concerning.

Another factor for a "big and heavy" person would be tire clearance - older CF bike are probably going to be from the age when 23mm was the default tire size and there's a good chance that they might not clear anything larger than a 25mm. My days of running 100+ psi are done - no reason for it. Get a bike that can clear 28s and run ~70psi or lower - with the general ****tiness of roads these days, it'll be faster and more comfy.

himespau 

Yeah, the whole crash history and undetectable damage, might make me want to stay away from used CF bikes. Also, I just think lugs are pretty, and I like shiny things (and am a fatty, so a little extra weight in the frame doesn't bother me), so my bikes are older than most CF (though are fitted with more modern parts).

Wooderson

Option 1 is to upgrade similar to what ljsense laid out (partially quoted below). I think that makes sense if you have a connection to this bike and/or maybe you aren't going to ride it a lot, and you just want to spend a little less. You could probably cut the cost a little if you're a savvy internet shopper, and consider gently used or new-take-off parts, and maybe go with a basic headset instead of a King. I might feel compelled to replace your wheels too, which might push the cost beyond what's practical. There are some decent, yet inexpensive wheelsets on the market that would make a noticeable difference, if you could find those gently used, that would be ideal (Campy Zondas, Fulcrum Racing 3, etc). Do that, and you might start to get closer to a 4lb weight loss.

Option 2... buying a new bike is always fun. A new bike would already come lighter, more comfortable, and everything more modern (gearing, brakes, wheels, geometry, stiffness/compliance, etc). No wrenching or part replacing required. Even if you bought a $800 entry level aluminum bike (i.e., Sora), it would be 'better' in every aspect just due to technological and manufacturing advances over the past 20 years. And from there, it only gets better (105 / Ultegra, carbon).

So I think it comes down to how connected you are to your 2002 Trek, how much money you want to spend, whether you like renovation projects, and maybe how much you plan to ride.

Please post back after you make your decision.

Psimet2001 

They end up feeling softer. IIRC this is due to mechanical breakdown of some bonding between layers in the layup. Can't remember where I was reading about it but was either Rukus who published a paper about it or from one of the studies through Specialized, etc. Might be worth searching the "Angry Asian" writings/blog or cycling tips.

I had a top racer who used to always say, "frames only last for about 2-3 year under me before they get too soft and wear out". I used to chuckle internally as an engineer. Then saw data to support that.

Outside of data - just ride a new one. For the 1,000 time. If you feel a difference that you enjoy then that's your own data point.