CliffordK

How long do America's Cup boats last? A year?

Of course they keep changing the rules based on who's country won the previous year.

MoAlpha

It’s now a corporate team sport very much like pro cycling and a hell of a lot more fun to watch than the old style races. The multihulls they race now are turned over each season because the rules and the technology are constantly evolving, but the old 12 Meter boats are still competing.

Seattle Forrest

It would drope.

Seattle Forrest

That's the problem with carbon fiber, it makes rules change.

Camilo

Longer than anyone need care about.

Camilo

I'm as carefull handling my steel, aluminum and carbon bikes because I don't want any of them to get dented or scratched by careless use. Such care prevents any damage to the carbon bike just like the others.The titanium bikes I'm equally careful of by habit, but I'm not nearly as worried about scratching.
Huh, whaaaat? you expect any sort of useable information?

"not sure", more like "no way".

Similar to what we've heard a lot in public statements and speeches "many people are saying..."

Branko D

It's illusory to talk about bike life span in terms of years. Bike frame fatigue which happens inevitably with all materials is a product of mileage, riding style, rider weight and power (out of the saddle grinding subjects the frame to much higher forces than climbing in the saddle, even higher than hitting road bumps), amount and severity of manufacturing defects (which happen, even in metals; just ask all the people who had a Ti frame break at the welds) and any impacts which may have created dents / cracks / delaminations / etc which may have weakened the material.

You can go down the rabbit hole of examining articles about bike and fork fatigue testing and so on, but it's really hard to translate how many cycles of what force to miles on the road, especially as there's a huge difference in terms of forces between eating up miles spinning on the flat on a smooth road, and a ride in the mountains over crap roads.

PeteHski

Not to mention it will depend largely on the individual bike model too. It's really a non-starter of a question to answer with any meaningful single number. Depending on the specific bike model and usage, expected lifespan could be anything from a few years to many decades. There's nothing inherent to carbon fibre that would limit any frame made out of it to a specific limited lifespan. It's not going to melt, dissolve or fall to pieces merely as a result of the passage of time.

Bob Ross

No, what you're seeing in either picture is simply two alternatives for the cosmetic layer, the first one a weave and the second one a random pattern*. The actual structural carbon in both examples is underneath the cosmetic layer, and is almost certainly unidirectional fiber...which looks like neither. Unidirectional fiber typically looks pretty benign/boring; sometimes you can determine the direction of the fibers, but if they are fine enough it just looks like matte gray plastic.

*Modulus Graphite, the company that invented the use of carbon fiber for guitar and bass necks, refers to that particular random pattern, the one that looks like "burnt MDF plywood" [sic] as KLD...an acronym for One Thousand Ladies Dancing.

PeteHski

Agreed on the cosmetic layer in the burnt patch look. The first one looks like a classic bi-directional weave. Not necessarily UD underneath either. Either way they are all sheet fabric layups and there is no "plank" type construction involved.

cxwrench

A properly designed and constructed carbon bicycle frame has a virtually infinite fatigue life. Under normal (not involving a crash that exceeds the limits of the frame construction) conditions a carbon frame will outlast the rider pretty easily.

Bob Ross

But "classic bi-directional weave" is (was) almost always used as a cosmetic layer only, because there are very few locations on a bicycle frame -- especially where two or more tubes join one another -- where you want structural fibers oriented uniformly at a perfect 90° angle to one another.

PeteHski

I don't believe that is true, but I'm not by any means a composites expert. There are properties of both unidirectional and woven bi-directional carbon that are beneficial to the combined structure. There may well be more emphasis on unidirectional layers in a high-end modern bike frame, but woven carbon is not merely for cosmetic use.

Seattle Forrest

The only thing people really need to know to come to the answer is there are millions of carbon bikes being ridden every day, some of them have seen decades of service. Carbon fiber isn't inherently unsuitable for bikes, no matter what scary things the internet says.

Koyote

Rode on my 20-year old cf fork again today. Did not die.

Will report back the next time I ride it.

Camilo

For our sake and the sake of your loved ones, you should install an app on your phone which will post here as well as text loved ones if your movement and heart both stop, with accelerometer data.

Koyote

Well, I did have one of the Specialized helmets with the ANGI system -- it was supposed to alert my wife if I crashed and was unconscious. But I figured she would just start working on her eHarmony profile rather than call an ambulance, so I turned it off.

znomit

Her profile is just fine as it is.

Lombard

Opinions are just that. And you know what they say about opinions? Might those opinions be from someone who wants to sell you a new bike?

As you can see here, there are plenty of riders who have ridden carbon bikes for more than 2 decades with no issues.

Redbullet

Noticed. But the takeaway for the moment is that nobody (yet) claimed here retiring road carbon bike due to failing during normal use. This might be a little piece of answer to my question.

Lombard

As far as I know, carbon does not deteriorate with age or for that matter mileage. It only "ages" with abuse such as riding it off a cliff or colliding with a motor vehicle. And in either of those scenarios, your carbon fiber frame will be the least of your worries.

cxwrench

A 'woven' piece of carbon is nearly always cosmetic. It doesn't provide any difference in stiffness in any direction because 50% of the material is always positioned perpendicular to the other 50%. A layer of unidirectional on the other hand can be positioned at an angle to the next layer if needed and completely change the flex/stiffness characteristics of the the part. During a visit to the Cervelo CA facility we made samples that were the size/shape of a popsicle stick. We did 2, the first had all the fibers running the length of the sample, the second had each layer at an opposing 45* angle to the length of the sample. The first you pretty much couldn't bend the length of the part, but was torsionally very flexible. The second you could easily bend lengthwise but was torsionally very rigid. Both were 4 sheets thick. Damon Rinard (head engineer for Cervelo at the time) said that weave was pretty much only used for cosmetic finish layers. It's strong against impacts but doesn't really change the flex you've designed into the layers under it.

Branko D

You could literally google composite fatigue and find out that it's wrong in two minutes - it deteriorates with (sometimes) age and particularly mileage.

I mean, seriously, folks, a cyclist climbing out of the saddle is a much more torquey machine than a typical motorcycle and the forces have a sideways and twisting component and are more choppy then a typical engine. Just climbing out of the saddle at a moderate 350W and 50 rpm is 66Nm of torque. How heavy is a motorcycle frame? A composite bike frame is 800 to 1100 grams, a quality metal one is 1500 to 1800 grams, of course they're all going to die to fatigue with enough miles.

Yesterday we were climbing a mountain and at the foot of the climb one of the riders had his old CF frame die, crack at the chainstay. It happens. ​​​​

cxwrench

What you're missing is that the bicycle frame is designed with a fatigue limit far far above that theoretical 66nm. That being the case if the frame is manufactured properly it will never get close enough to that limit to 'wear out'.

Branko D

86 Nm at a 25% climb

Metal frames are operating under the fatigue limit at all times? CF frames never fatigue? Why do they eventually crack, then?
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It’s a bold claim which doesn't seem to be supported by any literature which examines bicycle frame fatigue.