Carbon 'stays

Quoted post said:

Originally posted by Paul J
I am aware of the numerous discussions here concerning the "best" materials for frames, However.....A development in recent years for many manufacturers has been a move toward having an alloy main triangle with carbon fibre seat stays and chain stays. I would imagine that this would improve the comfort level somewhat. However how does this effect the overall integrity of the individual materials by being blended together. I would imagine that the integrity of a design would be better served by maintaining the same material throughout the entire frame whether it be carbon, alu, ti or steel. Are these combination frame longer lasting or do they have short lives? Anyone know?

Nothing new about bonding technology.Been around for years, as has mixed material bonding. Claim is that if done right the bond is stronger than the materials. . CF forks have aluminum dropouts,some have aluminum crowns,and steel or aluminum steerers bonded to the crown. Think about all that and their failure rate or lack of it.

In any reasonably decent manufacturer's frame, the bonded joint will be much stronger than the tubing. No doubt.

I had an older Trek 2300 that I rode for over five years (thousands of miles) that had the aluminum head tube, rear triangle, and bottom braket (each combined with the requisite lugs), which were bonded to carbon top, down and seat tubes (I attached a picture so you can see what I'm talking about). After a ton of miles the bonded frame junctures showed absolutely no signs of degradation. I sold the bike and I think they guy who bought it will be able to put thousands more miles on it. And I'm sure that bonding technology has advanced significantly since that frame was built!

Quoted post said:

Originally posted by Paul J
I am aware of the numerous discussions here concerning the "best" materials for frames, However.....A development in recent years for many manufacturers has been a move toward having an alloy main triangle with carbon fibre seat stays and chain stays. I would imagine that this would improve the comfort level somewhat. However how does this effect the overall integrity of the individual materials by being blended together. I would imagine that the integrity of a design would be better served by maintaining the same material throughout the entire frame whether it be carbon, alu, ti or steel. Are these combination frame longer lasting or do they have short lives? Anyone know?

I've read more that they really dont do much,more of a selling thing as everybody loves CF.

Quoted post said:

Originally posted by shokhead12
I've read more that they really dont do much,more of a selling thing as everybody loves CF.

Do much? It's a tube. It's not supposed to do much. They simply have different characteristics than other materials, in terms of weight, stiffness, and dampening. Sure, those differences are often really subtle -- particularly ones that deal with 'ride quality ' -- but when you're laying hundreds, or thousands, of bones on the table, you're entitled to be as exacting and fetish-driven as you like.

The most obvious difference afforded by carbon additions to aluminum or steel frames is a bit of weight savings.

It's a shame then that carbon stays don't actually save weight 😉

Quoted post said:

Originally posted by rek
It's a shame then that carbon stays don't actually save weight 😉

All carbon stays?

Rek, the point is taken that carbon isn't always lighter than similar structures in aluminum or steel. Thought that was a given. There are zero absolutes in this industry; there are different grades of carbon fiber, different grades of aluminum, steel, and ti, and even more ways to engineer them all. There are some heavy CF frames out there, and some ultralight alloy ones.

That doesn't change my point -- that generally speaking, a chief aim of carbon fiber integration into metal frames or components is weight savings. And generally speaking, if there's a quantifiable advantage to carbon fiber, weight savings is the easiest to attain. Ok?

Quoted post said:

Originally posted by lokstah
All

That doesn't change my point -- that generally speaking, a chief aim of carbon fiber integration into metal frames is weight savings. And generally speaking, if there's a quantifiable advantage to carbon fiber, weight savings is the easiest to attain. Ok?

CF stays on Al frames don't always save weight. There is usually more hype about ride and vibration. There are custom builders that will flatly state it often adds nothing,but the customers insist..... If you are not peddling CF in todays market, you are sucking hind [censored]. So, everyone is into it, real added value or not.

Thanks all for your input. A subject I am not too familiar with but have now gleaned some insight into. Thankyou.

Quoted post said:

Originally posted by boudreaux
CF stays on Al frames don't always save weight.

Seems to me lokstah acknowledged that pretty clearly in his post, he's just saying that where CF is used, weight savings are usually a major factor.

It's easy (and common, granted) for manufacturers to make CF bits and pieces that weigh as much as your average alloy bits and pieces. I'm fully willing to concede (actually, I did already) that not all CF stays save weight.

As for whether or not well-engineered CF can change ride quality for the better over well-engineered alloys -- well, as we all know, that's a highly contentious debate. With extreme respect to Boudreaux, I think the subject is beyond the dogma of his framebuilding friends. It's not worth arguing over.

Quoted post said:

Originally posted by lokstah
Do much? It's a tube. It's not supposed to do much. They simply have different characteristics than other materials, in terms of weight, stiffness, and dampening. Sure, those differences are often really subtle -- particularly ones that deal with 'ride quality ' -- but when you're laying hundreds, or thousands, of bones on the table, you're entitled to be as exacting and fetish-driven as you like.

The most obvious difference afforded by carbon additions to aluminum or steel frames is a bit of weight savings.

Right,they dont do much. Dumb statement.

Quoted post said:

Originally posted by mjw_byrne
Seems to me lokstah acknowledged that pretty clearly in his post, he's just saying that where CF is used, weight savings are usually a major factor.

If it don't save weight, how can weight savings be a major factor? Maybe I'm loosing something in the translatoin from gibberish and doubletalk.There have beem lots of CF stuff where weight was actually heavier,and the CF was nothing but expensive Bling.

Quoted post said:

Originally posted by boudreaux
CF stays on Al frames don't always save weight. There is usually more hype about ride and vibration. There are custom builders that will flatly state it often adds nothing,but the customers insist..... If you are not peddling CF in todays market, you are sucking hind [censored]. So, everyone is into it, real added value or not.

That's pretty much what my framebuilder here said also. He builds line of his stock-geometry frames with either CF rear stays, or an all CF tubeset.

As Martec and other Taiwan plants expand production and lower prices for these high-quality pieces, believe you'll see the CF stays and full CF tubesets on a lot more bikes in the future, both off-the-shelf and customs.

I suppose the weight savings issue is more convoluted than it once was. If I remember correctly, the earliest carbon fiber frames in use were treated as "climbing bikes" in pro circles, and were definitely intended to be lighter than their counterparts -- mostly steel.

Anyways, it's absolutely, factually clear that many modern aluminum tubesets and components -- and some ti ones also -- are built lighter than lots of carbon stuff out there. And as improvements in alloy manufacturing become more and more dramatic, we'll see more and more alloy stuff busting weight barriers previously held by carbon.

I don't deny that the materials industry is evolving, and that more marketing emphasis is placed on CF's more elusive qualities rather than its gram advantage as a result.

Quoted post said:

Originally posted by lokstah
I suppose the weight savings issue is more convoluted than it once was. If I remember correctly, the earliest carbon fiber frames in use were treated as "climbing bikes" in pro circles, and were definitely intended to be lighter than their counterparts -- mostly steel.

Well yes, but the question dealt with CF stays on an aluminum frame I believe. There is also CF and there is CF it's not all the same. It's possible to spec inexpensive generic stuff and There are manufacatures that spend alot of money on material that is made to their spec for specific purposes. There are a number of CF frames that are not lighter than alot of aluminum and and some have trouble shaving a real light steel frame.Making brord generalizations aout CF gets one in just as deep as generalizing about any other material.

Quoted post said:

Originally posted by boudreaux
If it don't save weight, how can weight savings be a major factor? Maybe I'm loosing something in the translatoin from gibberish and doubletalk.There have beem lots of CF stuff where weight was actually heavier,and the CF was nothing but expensive Bling.

Well what's this "if it don't save weight" business? Everyone knows it doesn't always save weight....but often it does, and since you seem to agree with the general idea that factors like "improved ride quality" and "vibration damping" are rather nebulous and probably more hype than anything else, it makes sense to conclude that weight saving is often a big factor in the decision to use CF.

Quoted post said:

Originally posted by boudreaux
If it don't save weight, how can weight savings be a major factor? Maybe I'm loosing something in the translatoin from gibberish and doubletalk.There have beem lots of CF stuff where weight was actually heavier,and the CF was nothing but expensive Bling.

I like that one,expensive Bling. It seems to go with cycling.

Quoted post said:

Originally posted by boudreaux
Well yes, but the question dealt with CF stays on an aluminum frame I believe. There is also CF and there is CF it's not all the same. It's possible to spec inexpensive generic stuff and There are manufacatures that spend alot of money on material that is made to their spec for specific purposes. There are a number of CF frames that are not lighter than alot of aluminum and and some have trouble shaving a real light steel frame.Making brord generalizations aout CF gets one in just as deep as generalizing about any other material.

Well, yes, boudreaux, but the generalization issue goes both ways as well. I've always loaded my comments with caveats like "generally speaking," and in the end, my posts on this subject have been no more one-sided than your own. Less so, actually.

It's clear to anyone familiar with your posts that you're not trying to suggest that carbon fiber is a worthless, heavy substance that has no place on a quality bike -- only that your dislike of all-things hyped has lead you to crusade from time to time against even balanced assesments of the stuff.

If you're simply trying to insist that it's not a wonder-material that always bests alloys in every respect, you're preaching to the deacon.