First, because I know someone is waiting with baited breath, I will retract my 24,000 mile statement.. Remeber I said I would check on that... We I musta been mixing half-and-half in the coffee at the local bagel shoppe <in my bike shorts which is a no-no... Oh wait that is another thread... Seems when I had the cream-cheese in my ears I converted the conversation from 24,000 miles left on the frame from... I'm about to go a distance approaching the circumference of the earh on my carbon bike...
Ah well...
As for the way this thread is going I see someone (same someone) showing an extreme partiality to carbon...
But at the same time while it is stated that carbon never fails they point out that another weakness of carbon, other than someone's bad design, is that where there is metal on metal you can experience a different type of failure... The cited example is the BB shell coming un-glued from the frame...
OK then let me add to that... What about drop outs? Hmmm... What about seat-post binder bolt contact areas? Hmmm...
And to make matters worse, this person has an adverse reaction to aluminum <but then so do I> to which we find that most of these pieces that are glued or run through the inside like a skeleton... Well these pieces are Aluminium so they are also going to cause the frame to fail... Sure it's not the carbon that fails but I think if a for drop out of aluminium cracks off and the front wheel pops out then you may find yourself picking up pieces of your carbon frame <after you pick up the pieces of yourself>...
Anyway to move on... Different materials for different jobs...
Examples:
Steel... Good cheap bikes... Commuter bikes... Touring bikes
Al... Good cheap bikes and can handle moisture better... But has a fixed cycle life.... Also has a harsher ride than steel... Commuter bikes.. Often used for ATBs.
Ti... Like steel for the ride, impervious to rusting or cycle failure <like steel> Good for high end bikes (because it is $$)
Carbon... Same as Ti but can be special molded into wierd forms to which could produce better ride... Requires special care with greases... Also contact areas must be metal so there are some glue-point issues.
Now let's take a different look...
Carbon Fading in sunlight...
1) My commuter bike is a cheap mountain bike made of Al because I don't care...
I live in South Florida where we get tons of sunlight. Saddles left out in the sun while I'm inside at work will fade and rot in no time. I use a garbage bag to cover the saddle and sack to make them last longer. The paint on the frame is faded on one side (the side that faces the sun) and the tires tend to rot off <on one side, you guessed it the side the sun is on>... Same for brake cables... The housings either rot away or rust from inside out <don't forget it rains in Fla and rains HARD>. Baking water into the frame <steel bikes have fun with this!>...
Now I know most of us don't leave our $3000 carbon and Ti bikes out on a bike rack 5 days a week in front of the office in the baking sun... It just aint right and it just aint smart...
Of course that is only if you scratch into the fibers as the epoxy could be UV resistive <but resistive indicates a lifetime>. This came from a check of the use of carbon fiber in, not aerospace, but aero-planes... "Sunlight can damage glass and carbon fiber cloth and resins used in composite-construction airplanes." So if you left your bike outside instead of inside the hanger for countless weeks/months on the tarmac of a shadless runway... Well... You get the idea...
Also I know someone with a Klein ATB... On the maiden voyage he spilled and dinged the frame on a rock. Yep it looks like someone took an oversized metal punch and knocked a dimple into the frame... No sever damage. paint is even intact. Assume there is some reduce in the life of the Al but not enough to toss the frame...
Nuf is Nuf. I will use steel and Al for frames where this makes sense, Ti is my choice because I like the feel of my Litespeed frame. My #1 riding buddy loves his Trek 5500 and I'm not knocking him for it... High end frames are exotic and so you can do or buy what you want... Be positive and friendly and remember that most of what we say here is talk and therefore laced with opinions...
Time to move on and ride those frames... None of them last for a lifetime... Well esp if you keep them indoors and keep typing...
Going to go take some more life off of my bike <and add some to my life!>...
See ya!