Carbon Rear Triangle Question on a ti bike- why?

[samtaylor1]

I am thinking about a new bike, have for a while now, and I was wondering why one would put a carbon rear triangle on a titantium frame?

Is it for looks? I don't really see any weight benefits. I would think that it reall wouldn't absorb the road any better then the ti? Is the carbon rear triangle just a cheap sexy tool to drive up the cost of the bike (when in actuality it is cheaper due to the fact that the material is cheaper?

Anyways would love some help.

Thanks

[samtaylor1]

I think I meant carbon stay

[mike p]

Cheaper and faster to build and it's all the rage.

Mike

[1centaur]

Yeah, carbon is just a marketing ploy, which is why the Ottrot is just...oh, I guess carbon really is different feeling, and it's a question of if YOU can feel it in any given location. For my money, almost all CF absorbs vibrations better than almost all metal, though if I were going to pick one spot where the difference is least obvious it would be the stays. Or you could go with the collective delusion theory.

[davids]

I could feel a real difference in 'road feel' - the tactile feedback to my hands and @ss - between a full-Ti Fierté, and Fierté with the carbon stay, and a Nove.

So, yeah. At least between those three bikes. I wouldn't try to generalize from my experience on these Serottas to any bike with a carbon stay...

My favorite was the Nove, followed closely by the full-Ti Fierté. Each had a distinct personality. I found the Fierté with carbon stays pretty much split the difference. All excellent bikes, atmo.

[victoryfactory]

I had a carbon stay Concours Ti
I thought it too stiff with no dicernable weight benefit.
Went with an all Ti legend which is much smoother riding.
Although I believe that carbon probably is the future for bike frames,
I think the marketeers who tout it's "smooth" or Vibration absorbing
ride characteristics and lightness are overstating a buzz word
and confusing the issue.

It's funny, on the one hand some talk about carbon's stiffness
and some say it's non vibrating and smooth. Can it be both?

As with any frame material, I think the ride can be dialed in by a good
designer to give a range of attributes. It's the builder, not the material!

The problem with those "plug-in" carbon stays mentioned above could be
that, in general, they are designed seperately from the frame and then
sourced by the frame builder and plugged into his design, hardly synergistic.
I would think that Serotta gives a little more thought to this marriage of
materials than the average builder, but hybrid frames still make me think
of Frankenstein's monster

VF

[djg]

I know that the market provides many choices, and that builders often give you tubing choices, but guess I'd be inclined to default to the position that says that you buy a frameset for its overall properties -- or because you like the overall design or trust the builder -- rather than because of its parts. If there's a stock bike you like, I wouldn't worry about the combination. If there's a builder you're talking to, ask the builder what he'd have in mind for you.

I happen to have a bike that sports a titanium main triangle and a cf rear triange (and fork). I bought a Colnago CT1 about 5 years ago because I had decided, for various reasons, that I wanted that particular frame (and had a line on the right thing from the right place ...). No regrets--the bike has been great. But I wasn't really scouring the market for that particular materials combination, and if I were searching for a replacement frame the general idea of ti main triangle and cf rear would probably be pretty low on my list of preferences (if not just absent from it).

[RPS]

From a purely technical perspective (setting aside marketing, fads, etc…), it is helpful when comparing carbon fiber composites to titanium to keep in mind that carbon is anisotropic; which means that the mechanical properties are not the same in all directions. The stiffness of carbon when placed in compression can be much lower than when in tension.

On a traditional bicycle the seatstays -- which transmit the vertical forces from the rear wheel to the saddle area -- almost always remain in compression, so carbon fiber if used properly can soften the ride to some degree. However, IMHO this is useful mostly on very low amplitude vibration. On bumps and rough roads, a lot more vertical compliance is needed to isolate the rider effectively from road vibration and shock.

[victoryfactory]

From a purely technical perspective (setting aside marketing, fads, etc…), it is helpful when comparing carbon fiber composites to titanium to keep in mind that carbon is anisotropic; which means that the mechanical properties are not the same in all directions. The stiffness of carbon when placed in compression can be much lower than when in tension.

On a traditional bicycle the seatstays -- which transmit the vertical forces from the rear wheel to the saddle area -- almost always remain in compression, so carbon fiber if used properly can soften the ride to some degree. However, IMHO this is useful mostly on very low amplitude vibration. On bumps and rough roads, a lot more vertical compliance is needed to isolate the rider effectively from road vibration and shock.

That's exactly what I was going to say.

But seriously, thanks for that explanation. I reaffirms my belief that carbon
is the frame material of the future as soon as everybody focuses on all
of it's possibilities. There seems to be a lot of innovation room left in the
world of carbon, compared to other "classic" frame materials.

VF

[Climb01742]

serotta's purchase of the reynold's fabrication facility has gotten most of the focus, but there's a dude there -- i forget his name -- who is supposed to know just about everything there is to know about carbon and it's promise/possibilities. his knowledge may prove quite useful to serotta.

[RPS]

There seems to be a lot of innovation room left in the
world of carbon, compared to other "classic" frame materials.VFI like to think there is a lot of room left for innovation in all materials. The main limitation from my perspective is that designers and engineers are more comfortable looking for evolutionary rather than revolutionary improvements. It’s much less risky – both financially and career wise.

The answer to the question being asked is not entirely in the material. A nice car with super-stiff titanium or carbon springs would still ride like a truck.

[samtaylor1]

Thanks for your responses.

I talked to my builder Scott and we went back and forth as to what would be the best. I am a 6'7" 280 so durability is a big issue- thus a bike that is all one material will be strongest (also it will be lighter- not a big issue for me). But suppusedly the carbon seat stays could add some stiffness and a bit of dampening (though he was not sure it was worth the price difference).

Anyways, more to think about.

[vaxn8r]

Sam, I have owned 2 all ti rigs and 2 CF rigs. While the CF bikes are certainly comfortable (all the while providing more than adequate drive train efficiency) my Legend is the most comfortable road bke I've ever owned. It might sacrifice maybe 2% of the "jump" people talk about, but every time I ride it it puts a smile on my face and I think "all day man!" It is a blast to ride. Great combination of comfort and efficiency.

I also own a 1992 Litespeed Classic. It's not super light nor is it super compliant. It is beautiful and for some reason I just had to have that bike. But it's never inspired me riding it. Just saying that generic "ti" doesn't necessarily all mean the same thing. I bet somebody could make a killer ti/CF bike...er...like Serotta.

[sg8357]

Thanks for your responses.

I talked to my builder Scott and we went back and forth as to what would be the best. I am a 6'7" 280 so durability is a big issue-.

Can you get a 30mm to 35mm tire with the rear carbon stays ?
How about 135mm rear hubs ?

I'm 210 and like 32mm tires in winter, AZ chunk & seal roads, 35mm.


Scott G.

[Big Dan]

All Ti Serotta Legend.... One of the best Ti frames around...atmo... :)

[Ahneida Ride]

Sam

I demoed a Ottrott ST a few weeks ago built for a 6'5 270 pound guy.
The ride was quite exemplary. very smooth, in spite of being constructed
with Serotta's stiffest tubes. I was impressed.

My normal ride is an all Ti Legend. For comfort I have a Brooks B67.
I love the bike.

Which is better? I can't honestly say. But I can assure you that the Ottrott
is not a marketing ploy. A gross misconception, I had always believed.

Rest assured that Serotta is capable of building you a perfect frame.
Just ensure that you have a competent fitter. Has this fitter had experience
with Clydesdales?

Uncle William, our other resident monster, unfortunaltly procured the services of a less then competent individual.

Ask questions .... you may wish to consider an Top Tube with a small
slope. On a large frame a small slope is not even perceptible.

[samtaylor1]

Fortunately Scott built me an awesome ti cross bike. Just can't afford Serotta, and I have decided I really love working with the little local guy with the great rep. Scott Quiring is the truth.

This forum is definitly great.

[obtuse]

Fortunately Scott built me an awesome ti cross bike. Just can't afford Serotta, and I have decided I really love working with the little local guy with the great rep. Scott Quiring is the truth.

This forum is definitly great.


i though paul pierce was the truth.

obtuse