Rydmore

I have a question, maybe somebody out there can help? I have a choice of buying a Trek 5200 Carbon Fibre (2002) that I can get at a great deal. Or I just finished building a 1989 Pinarello Asolo, with Campy 9 speed. I hacve ridden them both for the past 2 weeks, and cannot make a choice. Any ideas out there.

Thanks,
Matt

RoAdRaGeR

Although I would probably go for the Trek 5200, it all comes down to the ride. Which bike feels/rides better?

orguasch

Keep both bikes, that way you had the cake and you also eat the pie, very few people have that kind of opportunity

catfish

I just bought a 5200 for a great price and love it my other road bike is a 2120 and i cannot part with it either ILL keep both bikes good luck with a decision
catfish

orguasch

I totally agree with your observation, you keep on looking for new bikes and drool over this new bike and when you have the opportunity to buy them, you don't want to sell the old one that my friend is greediness, and I am also guilty of the thing called greediness when it comes about bikes

Rydmore

I appreciate your reponse's, but I can only buy one bike. The Pinarello is a 12 year old frame, never ridden, but with brand new campy stuff on it. It has a new carbon fork, but the Trek is also
so nice. I like the campy group better than Shimano, but the frame on the Trek is nicer. I test ride them, and can't make up my mind.

Trekaholic

I can't add anything intelligent about the Pinarello.

I can say, however, that I can't imagine anyone being disappointed with a Trek 5200. Mine has 8,900 miles on it and I still get a kick out of riding it. I've never regretted shelling out the bucks for it.

Wait a minute, what am I doing writing to you... I think I'll go for a spin!

lotek 

The Pinarello is a classic, traditional Italian design
executed with Columbus or Dedaccai tubing.
The Trek is exactly like every other Trek out there
(well ok, not like MINE!), this isn't to say thats a bad
thing, I just think that the Pinarello is a better "find".
NOS frame?
Steel frames have the archtypical ride, the one that
everyone strives for in other materials.
The Pinarello will be if not more lively than the Trek
will transmit more road feel than the carbon fibre.
The Carbon Fork on it will dampen and soak up any
road bumps.
For my money I'd buy the Pinarello.
That said, you should know I have a Trek which
I absolutely love.
Marty

Brian Ratliff

I don't know if longitivity is a concern (though with your choice of bikes maybe not), but steel + high quality campy will last to pass on to your great grand kid if taken care of properly. Carbon fiber will eventually fail, and Shimano is almost non-servicable, only replaceable.

That said, it is up to what you like in a ride. I prefer my steel Univega road bike, but that may be just my wallet speaking .

Trekaholic

Brian: Re: your comment that "Carbon fiber will eventually fail,"

Hmmm.....

I've heard this before but never seen any solid proof of this statement. I can't help but think that carbon fiber's fatigue resistance is far superior to steel. This should translate into greater longevity, assuming the absence of abuse, neglect, or major accidents. Think of where it's used: aircraft wings and propellers. Granted it has weight advantage for such applications vs. steel, but there's no way it could be used in such applications unless its fatigue performance were extraordinary. If carbon fiber can handle the tremendous loads and shearing forces in aircraft, then the stresses it sees in a bike frame are nothing by comparison.

I even thought myself that carbon fiber's impact resistance would be worse - but one of the selling points when I bought my carbon bike was when the salesman in the store let me hit one of these frames with a tire pump (And it was a metal floor pump too, not one of those micropumps). He wouldn't let me do the same with an aluminum or steel frame.

I'll grant that steel is easier to repair, but so far I'm unconvinced that carbon fiber should take a back seat to other materials in terms of longevity. I've had two major crashes with my carbon fiber bike, and it held up better than I did in each case.

Much of a frame's longevity depends on how stresses are concentrated on it. Fortunately, these issues are well known to frame designers who can compensate for what would be weakness where expected stress concentrators might be a problem. That's why, for example, one sees large radii at joints where sharp seams are the norm in other materials.

I've said elsewhere in these forums and I'll say it again - don't think of carbon fiber as a "cheap plastic" frame - it's a highly engineered material that offers outstanding strength, stiffness (although maybe unidirectional), and responsiveness while offering a delightfully smooth ride. For some that ride may feel too dull -- but for some of us that's a Godsend.

Trekaholic

https://www.calfeedesign.com/twp.txt

Check out this link for a technical white paper on the use of carbon fiber in bicycle frames....

Trekaholic

Brian Ratliff

Don't get me wrong, I did not say that carbon fiber was weak. The carbon fibers making up the weave are much stronger than steel.

In the realm of materials properties, not all is obvious to be seen. Carbon fiber itself actually transmits vibration better than aluminum even. It is the fact it is wound and surrounded by a softer resin matrix that makes for its vibration damping tendencies.

In the realm of fatigue life, steel and titanium (I believe) are the only two materials which possess an endurance limit, meaning below a certain stress, the material can ideally undergo an infinite (or close enough) number of load cycles without failing. All other metals, and most other materials do not have this, and at any load, they will fail after a finite number of load cycles. Do not confuse strength with fatigue life.

The carbon fiber matrix will eventually debond and lose its elasticity. Carbon fiber is very strong, but does not stretch. The resin matrix is what gives a carbon fiber weave (or fiberglass for that matter) its elasticity or springiness. Once the resin is degraded, the carbon fibers will quickly fail due to very high stresses because the matrix is not there to distribute the stress.

As for aircraft, they are made out of aluminum mostly, carbon fiber, some steel, and some Ti. The fatigue life of an airplane is finite too, and there are large costs associated with finding out how long a plane will last.

Hope I did not overwhelm anyone, but this is what happens from a materials science point of view. That said, carbon fiber bikes are probably built to last at least a lifetime of hard cycling. It is just that a steel bike will last forever (ideally of course ). I did try the Trek once, and it is a dream. It accelerates much faster than my steel Univega (and my Al Trek) and has a sweet ride.