Carbon frame "life expectancy"

Discussion in 'Cycling Equipment' started by cpalomo, Jul 2, 2003.

  1. IronDonut

    IronDonut New Member

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    What a bunch of bullshit. Steel and titanium will never fail if the flexing is kept within the design parameters of the material.

    This is exactly why the valve spings in a 10 year old car keep springing even after hundreds of millions of cycles.




     


  2. artmichalek

    artmichalek New Member

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    Before you go telling people what's bullshit you should do some reading on stress corrosion cracking. There's no such thing as never, especially when it comes to fatigue failure. Carbon fiber is used in lots of spring applications, such as the rear suspension in the new Corvettes. The reason it isn't used for valve springs has more to do with natural frequency than fatigue life.
     
  3. Jaguar27

    Jaguar27 New Member

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    :D :D :D
    I find wrapping it in Tin Foil works better, the really thin stuff doesn't add much weight either!!
     
  4. Jaguar27

    Jaguar27 New Member

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    A Falcon?? wow!! I'd like one of those, my first Road Bike was a Coventry Eagle, in fact, I missed one on ebay a few weeks ago...would it be possible to post/send some Pics??
    Coventry (my home town) was pretty famous for it's Bicycles years ago, but not unlike it's Car industry, the Businesses were mis-managed and they've all died...


     
  5. IronDonut

    IronDonut New Member

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    My bike sits in the direct sun a lot. Generally I ride after work and the bike is on my car rack all day several times a week.

    Of course I don't care one bit about UV rays my bike is bare titanium. Which you could leave out in the sun for the next 100 years with no damage.



     
  6. IronDonut

    IronDonut New Member

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    Corvette springs are fiberglass not carbon fiber. Fiberglass has a good history in flexy applications boat hulls for example.




     
  7. cydewaze

    cydewaze New Member

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    The new Corvette springs are a composite material.

    Better call Chevy before someone dies!
     
  8. dhk

    dhk New Member

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    Agree CF isn't the right choice if you leave your bike in the hot sun; Ti is a better choice for a bike left out in the sun and rain. If you left you old CF bikes baking in the sun as well, that could have contributed to their quick demise.

    Again, it all gets down to choosing the right equipment for your particular useage. The lightest materials and frames certainly aren't for everyone. It's too bad they get marketed as "better" for all applications.
     
  9. cydewaze

    cydewaze New Member

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    I want a bamboo bike. :)
     
  10. IronDonut

    IronDonut New Member

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    You're not the sharpest tool in the box are you?

    Both fiberglass and carbon fiber are composites. The Corvette springs always have been and continue to be fiberglass not carbon fiber.

    There are a lot of similarities between carbon fiber and fiberglass (like there are between aluminum and steel) but they aren't the same thing.



     
  11. cydewaze

    cydewaze New Member

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    No, but I'm a hell of a lot sharper than you'll ever be.

    Did I say the springs were carbon? No, you had to LIE and pretend I did, because unless you pull things out of context, you don't have a leg to stand on.

    Stop making stuff up, and stop sticking words in peoples mouths. If you can't get your facts straight, trying to change what other people say is NOT going to help.

    For the record, my post about the leaf springs was meant to point out that the material in them has changed from the old Corvettes. They're not just "fiberglass" anymore.
     
  12. IronDonut

    IronDonut New Member

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    Sure you are.... thats why you are a web designer. haha.

    I can see the anger in how you are pounding on your keyboard.

    I win.




     
  13. IEatRice4Dinner

    IEatRice4Dinner New Member

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    carbon wont last forever, nothing will... but like any frame it has to do with alot of factors, rider weight,racing,crashes,road conditions, just to name a few. Lance DOES NOT RIDE an off the shelf madone. The frame and bottom bracket is beefed up a bit. A large # of trek and lemond carbon frames fail at the bottom bracket shell, might tell ya something. a shop i worked for sold a carbon frame lemond to a 60 year old lady (120lbs)who road alot, not racing just casual riding... she went through 2 frames because 2 bottom bracket shells cracked after some 5k miles each.
    As far as no "high end" steel road bikes... do a yahoo search there is loads of awsome steel luged bikes, and they are light. They arnt cheap... but are made to fit you. http://www.waterfordbikes.com here is a link for the ppl that like this kinda stuff... steel luged frames is b4 my time, id gladly ride a ti or carbon frame if i had the money :) currently on aluminum
     
  14. IronDonut

    IronDonut New Member

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    The crew I race with are sponsored by a Trek / Fisher dealer. All of them ride Trek products. The carbon mountain bikes have been failing at a fairly high rate. The aluminum and aluminum/carbon Fishers have been failing at a nearly 100% rate.

    A few of the guys have broken so many bikes that they switched to Titus Racer-Xs. I switched to Litespeed.

    I don't know about the road bikes but I don't think the Trek mountain bikes are built to stand the abuse of a regular racing / training program.

    My opinion.


     
  15. staller

    staller New Member

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    I've got a mate in a pro team with carbon bikes and they all cracked in the first 2 months of use... I put that down to faulty assembly.

    The reason I prefer alu over carbon is crashability - if such a word exists.
    I have seen an alu bike tangle with a carbon in a big get off - the alu was a ride home but the carbon tore the entire rear stay assembly off like paper.

    If you race or ride with dodgy boys then this is important.
     
  16. WP33

    WP33 New Member

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    ID is full of shit. Period. I've had a carbon frame, carbon fork, blah blah blah, for six months now, put about 2500 miles on it, and I'm sitting about 200 pounds. No problems. If a 200+ pound guy (what I was when I got it) can't break a frame torquing it hard and pounding on it like I have, then no one can. F 'im. Buy carbon. Love carbon.
     
  17. patentcad

    patentcad New Member

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    That's classy, eh?

    Bottom line is that EVERYTHING breaks - or CAN break - eventually. My 1991 Merlin - a titanium frame - broke in the middle of the chainstay and downtube @ 40K miles. And I weigh 160-170, not 200lbs. I ride about 7K miles annually, so that was 5+ seasons and *blammo*, new bike time. By the way, I had purchased it with a few hundred miles on it, so I wasn't the original owner. Merlin told me to hump the monkey. I don't buy Merlin bikes anymore. My Ibis Ti road has about 30K miles on it - and it just went out to Spectrum Cycles for refinishing, so it's still in business.

    I ride an aluminum/carbon Cannondale Six13 now - just purchased it 3 weeks back - and if it breaks I get a new frame as long as Cannondale is in business. And they've been around for 30 years or so....

    By the way, that Six13 is by far the best racing bike I've ever ridden, and I've ridden a lot of them.
     
  18. IronDonut

    IronDonut New Member

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    Heres the thing these bikes are made as light as possible. There is a direct relationship between durability and weight. You could make a bike that lasted forever but it would be to heavy to be marketed. Would anyone buy a 5lb thickwall Ti frame? Or a 9lb steel frame? Probably not but they'd last forever.




     
  19. patentcad

    patentcad New Member

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    Very true. Interesting aside: you'd THINK that titanium is indestructible. I once rode with an aerospace engineer who told me that while Ti is great for things like jet engines and aircraft, it's actually MORE susceptible to fatigue from the high frequency vibrations a road bike is subjected to. Of course your 150-200lb physique over a few thousand road miles may not stress Ti quite as dramatically as a multi-ton jet fighter, but it does so in a different - and apparently more insidious- manner. On the other hand lots of conversations with shops that sell plenty of Ti bikes and Ti frame builders lead me to believe that 40K mi. Merlin frame failure is the exception to the general rule - like maybe 5-10% of them would fail that way (which means overall that would be 1-2% since the vast majority of high end bicycles sold never really see 30-45K miles). And my Ibis is newer (1995) double butted Ti tubing, so hopefully @ 30K miles, and now my secondary bike, it will last me another 5-10 years.

    At that point I'll be 58 years old. And if I'm still riding ANYTHING I'll be very happy : ).
     
  20. dhk

    dhk New Member

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    ??? Have you read your C'dale warranty? Like all the major brands, it specifically excludes fatigue failures due to normal wearout. Cannondale, of all companies, are upfront about admitting their frames aren't designed to last forever.
     
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