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Opinion on carbon seat stays?(46 posts)

Opinion on carbon seat stays?Jowan
Dec 17, 2002 2:04 PM
When looking for a new frame I noticed that a lot of recent models come with pre-fabricated carbon seatstays (fi DEDA or Columbus).I was on a bike show recently and it seemed to me that all frames with carbon seatstays and forks tend to look alike. Looking great, but not a lot of difference in design.

Does anyone have any experience with these combined alu/carbon or steel/carbon frames. It's promised to give a more efficent frame while improving comfort and dampening. Is this really true or is it just this years marketing gimmick?

Jowan
re: Opinion on carbon seat stays?niteschaos
Dec 17, 2002 3:10 PM
I prefer Cannondales path on this one. Just as vibration damping but lighter than adding epoxy and carbon to the mix by having curved seat stays. I also am glad that the Vortex, which I haven't ridden, but one of my friends races on one and he says its comfortable, and it has curved stays of the same material as the frame.

I also like the looks of more conventional non-carbon seastays.
re: Opinion on carbon seat stays?Heron Todd
Dec 17, 2002 3:31 PM
>It's promised to give a more efficent frame while improving comfort and dampening. Is this really true or is it just this years marketing gimmick?

Marketing gimmick (same thing with curved stays). These stays do several things:
- look cool
- cost more
- weigh more

Todd Kuzma
Heron Bicycles
LaSalle, IL 815-223-1776
http://www.heronbicycles.com
Todd is right onKerry
Dec 17, 2002 4:20 PM
Beyond that, it is another set of joints of dissimilar materials in the frame. Adhesives and joining technology have improved significantly, but it is still a collection of points of failure that simply doesn't exist in a normal frame.
just a little biased?? nmmotta
Dec 17, 2002 4:20 PM
just a little biased?? nmHeron Todd
Dec 17, 2002 8:09 PM
No, not really. The same Taiwanese suppliers who sell this stuff to the Euro-builders have approached me as well. It would be quite easy to glue some carbon stays in our frames. I've decided not to do that, however, because there is no good reason to.

FWIW, I've spoken with framebuilders (the guys whose names appear on the downtubes) who offer these stays, and they will admit off-the-record (or at least without the marketing guys around) that they offer nothing but looks.

Todd Kuzma
Heron Bicycles
LaSalle, IL
http://www.heronbicycles.com/
just a little biased?? nmmotta
Dec 18, 2002 5:37 PM
What do lugs add to a frame? Is that not just another breaking point, much like the bonded joints of the carbon stays? Doesn't a TIG weld or fillet braze hold just as good and offer the same type of ride? It seems to me that lugs limit the the builder in size and geometry and do nothing but add weight to the finished product. So really all lugs offer are looks, at least for some people.
just a little biased?? nmHeron Todd
Dec 18, 2002 5:49 PM
>What do lugs add to a frame? Is that not just another breaking point, much like the bonded joints of the carbon stays? Doesn't a TIG weld or fillet braze hold just as good and offer the same type of ride?

Lugs, if properly designed, offer an external reinforcement to the joint. If improperly designed, they can cause stress risers that can lead to failure. Generally speaking, you are correct that TIG-welding is just as good these days.

Lugged frames are for those who appreciate the look, but more than that, appreciate the craftsmanship required. Mikasa crystal costs about 20% what Waterford crystal does and it's perfect because it is machine made. The Waterford crystal shows the imperfections of each cut because it is made by hand. People pay the premium for Waterford crystal because they appreciate the craftsmanship.

I can source foreign-made aluminum road frames made to my specifications and get them for less than $100 painted and shipped to the US. TIG-welding aluminum is currently the cheapest method to build a frame. That's why Huffy does it (their frames cost them less than $10 finished).

So, I can certainly make frames cheaper. I can make frames lighter. However, there are plenty of folks already doing that. I offer traditionally-made, handcrafted frames for folks who appreciate that.

BTW, our upcoming titanium Herons are NOT lugged (although I was tempted!).

Todd Kuzma
Heron Bicycles
LaSalle, IL 815-223-1776
http://www.heronbicycles.com
just a little biased?? nmmotta
Dec 18, 2002 6:13 PM
You are inferring that because Tig welding is the least expensive way to build a frame that it is somehow inferior, that is just incorrect. IF would take you to task on that with the steel frames they build and the robots in Taiwan would also be very unhappy with you.
just a little biased?? nmHeron Todd
Dec 18, 2002 7:03 PM
>You are inferring that because Tig welding is the least expensive way to build a frame that it is somehow inferior, that is just incorrect.

That's not what I am saying. What I am saying is that some people prefer a product with craftsmanship (not that TIG welding, when done by hand, is not craftsmanship - it's just different). The Mikasa crystal IS better than the Waterford, but the Waterford still commands 5 times the price because of its story.

Personally, I like the fact that a craftsman in Wisconsin rather than a robot in Taiwan built my frame. That's not saying that it's any better than the robot-built frame or that it's wrong to prefer the robot-built frame. It's just saying that it's different, and some folks prefer it.

Certainly, there is enough room in the marketplace to accomodate different methods of production and different customer preferences? I even think that there is room in the marketplace for carbon stays if that's what some folks prefer. What I DO object to is the claim that there is some technical superiority in them.

If you think carbon stays look cool (and carbon does look cool) and that turns you on, then great. If you think that lugs look cool, then that's great too.

Todd Kuzma
Heron Bicycles
LaSalle, IL
http://www.heronbicycles.com/
re: Opinion on carbon seat stays?Fez
Dec 17, 2002 4:34 PM
i agree that carbon seat stays cost and weigh more.

but are curved stays a marketing gimmick and nothing else?
I'm inclined to agree....joekm
Dec 18, 2002 6:41 AM
Carbon fibre, being a composite, is very "tunable" so, with careful design, you may reap some benefit. If nothing else, you should expect dampening of high frequency noise. However, it appears to me that the typical frame builder gets his tubes "off the rack" so to speak. As a result, I'm a little skeptical and somewhat concerned that all you are really doing is increasing the fatigue rate at critical stress points.

I would say that, if you are going to go carbon, either make the entire bike carbon or at least the entire rear end. Also, go with a company that's made a few carbon frames as opposed to someone who has just recently added carbon components to their lineup.

BTW - that really cool looking coarse weave on the outer layer of most carbon fibre tubes is only cosmetic. At most, it protects the real contributing portion of the layup from abrasion damage.
re: Opinion on carbon seat stays?DINOSAUR
Dec 17, 2002 4:51 PM
I've often thought about this when I'm riding my old Klein Quantum Race. Just about all the road vibration and shock is transmitted from the front wheel, up the fork, to your stem and handlebars. If your bike has a nice carbon fork, you don't run too high of a psi on your tires and you have a quality stem and bars, how are cf seat stays going to improve the ride? Or is it worth forking over that much more money for something that won't make much difference?
I'm in the dark here, I've never ridden a bike with cf seatstays. I like my Klein the way it is and I intend to upgrade it and keep it for many more moons...not that I wouldn't mind having a new Klein Q-Pro..actually my answer was just to stick with steel...that's my choice for my main ride...
re: Opinion on carbon seat stays?The Human G-Nome
Dec 17, 2002 5:11 PM
well, i'm taking my first detour into carbon seatstays. i would think that you can't just make a huge generalization about this "gimmick" and that different manufacturers, different frame materials and certainly different geometries might have something to do with quality of ride in relation to carbon stays. i've been told that stays actually can make a difference, but that a complete rear triangle makes no more difference then "just the stays".

further, how muck difference does a carbon stem make? carbon handlebars? carbon wheels? (i would think a lot on this one)

i think the verdict is still out on all of these "innovations".
re: Opinion on carbon seat stays?Heron Todd
Dec 17, 2002 8:14 PM
>further, how muck difference does a carbon stem make? carbon handlebars? carbon wheels? (i would think a lot on this one)

Something like a fork, handlebars, or a seatpost can offer a difference in ride quality because these things are cantilevered off of the bike. That is, they are fixed at one end but not at the other. So, they are free to flex.

The rear triangle of a bicycle frame is an inherently stiff structure. That is why the tubing used there can be such a smaller diameter than used in the rest of the frame. The stays are not going to flex by any detectable amount no matter the material.

Todd Kuzma
Heron Bicycles
LaSalle, IL
http://www.heronbicycles.com/
Once again, I find myself in agreement...joekm
Dec 18, 2002 7:06 AM
Of course, if you arc or wishbone the seat stays, you are essentially adding a rear suspension in the form of a reasonably stiff spring. The price of that modification is increased weight and greater fatigue loading at the verticies of the rear triangle due to the larger deflection.

I seem to recall that this was first done on mountain bikes. In that case, it could be argued that you are adding rear compliance without the weight of a rear shock absorber.

As I've posted in the thread before, I'm not a frame builder. However, my instincts would tell me to concentrate more on lateral stiffness at the rear triangle and let vertical compliance take care of itself (unless ride quality is really that bad and it can't be fixed by tires, seatpost, seat, etc.)
Carbon still in it's early years?DINOSAUR
Dec 18, 2002 7:54 AM
I remember when the first aluminum bikes came out and they were less to be desired (Alan?). Now aluminum bikes are being ridden by the pro peloton. So my thinking is that we are still in the early years with carbon fiber. I never thought in my wildest dreams that I would be ridding an al bike, so it's best never to say never. Ernesto puts carbon forks on his steel bikes (I've read that steel forks are no longer an option with Colnago), so there must be something to it. If I were a rich man (and I'm not) I'd have a stable of 4 bikes, steel, al, ti, and cf. If it evers stops raining on the west coast I can get off this computer that's smarter then me and get some riding in and I could care less what type of bike it is..just idle thoughts on a wet day...
As always, those who haven't even ridden one are against them!Tig
Dec 17, 2002 5:11 PM
Marketing gimmick? Sometimes. Nothing new for some manufacturers!
Cost more? Yes, but they shouldn't since they are much easier to build with (which is one reason they are being used).
Weigh more? More than aluminum, less than steel and Ti, and gee-whiz, the same as carbon fiber! LOL -If 100 grams weight over comparable aluminum stays is that bad, maybe we should really cut some weight, like no water bottles or go on a big diet.
Are they durable? As durable as a CF fork (depending on manufacturer), and almost everyone here has one. Most forks are bonded with aluminum, but the adhesive layer prevents galvanic corrosion. If you get hit hard by a car, yes, they will fail... so will everything else, including your fragile body.

Not all CF seat stays are the same. We have yet to see any decent research on which ones have what desirable properties over the others. After riding a bike (Merckx Fuga) with them for 9 months and over 6000 miles, I have found them to be very stiff, helping to strengthen the rear triangle without adding harshness like some stiffer tubing choices can do. Are they comfortable? Yes, they do a nice job of dampening higher frequency vibrations up to the seatpost joint. They do not compress or flex laterally. Similar to CF forks (but with the added structural benefit of a complete 3-D triangle with the chain stays and seat tube) they are built with the fibers layed up for desired directional strength.

There are many ways do achieve a desired ride, and this is just one of them. It is not the almighty answer, but a different approach. Anyone who hasn't spent many hours on a bike with them shouldn't comment about CF stays. My bike isn't as comfy as an OCLV or lugged steel (but not a too-distant third), but it isn't supposed to be. It is much stiffer in the bottom bracket than they are, and accelerating and climbing feel incredible comparatively. It IS much more comfortable riding long distance than my Cannondales and Trek aluminum frames could ever be.

Combine this with a comfy saddle, bars, wheels, decent width tires at lower pressure, and I get a wonderful, all day ride with plenty of bottom bracket stiffness. Tires/pressure/wheels/seat/bars/geometry and usage of frame materials are more important than the material in itself.
As always, those who haven't even ridden one are against them!The Human G-Nome
Dec 17, 2002 5:16 PM
hey, good post!
That is a good post..DINOSAUR
Dec 17, 2002 5:27 PM
Hey we are all here to learn...I never thought I would be riding an al bike to start with..I found my just slapping a ti railed saddle on my Klein it did a lot to improve the ride...dialing in the right tire pressure for your body weight was another thing...I just wonder if my Klein rides so nice and smooth how it could be improved...but old man Gary Klein knows what he is doing....wish I had the money for one of those Klein Q-Pros...or a new anything...like a new 24 year old body..
That is a good post..Leroy
Dec 18, 2002 5:08 AM
Same here, Dino. I've had the exact same experience with a cannondale. I had been entirely a steel frame guy, and got the c'dale almost on a whim, and what do you know, it's a great ride. I do not see how cf stays could improve it.
As always, those who haven't even ridden one are against them!Heron Todd
Dec 17, 2002 8:31 PM
#1 - You are making some big assumptions about those who oppose CF stays. Are you sure that none of us have ridden them?

#2 - Just having ridden CF stays is really not enough to make a judgement. To make a fair judgement, you need to have ridden 2 bikes that are identical except for the stays. Same tires, tire pressure, stem, saddle, seatpost, etc.

#3 - Having such a comparison can still be colored by your expectations. Riders almost universally claimed that deep dish wheels like Specialized tri-spokes and Campy Shamals rode harshly. Yet, test data showed that they actually had GREATER vertical deflection under load than a 36H wheel with box section rims. Similarly, in food industry taste tests, most people report that red, unflavored gelatin actually tastes like it is strawberry or cherry-flavored.

#4 -It is quite clear that there has been no testing showing what some people have claimed to feel. What drove manufacturers to add stays was not any revelation or science which concluded that it would improve ride quality, but the fact that the stays could be mass-produced and glued into existing designs.

>Weigh more? More than aluminum, less than steel and Ti, and gee-whiz, the same as carbon fiber!

They weigh more than a comparable stay made with other materials because of the necessary plugs and epoxy. You are essentially taking a traditionally-built frame, cutting a section of stay out, welding in a plug, and gluing in the CF section. This weighs more than if you would have left the original stay intact.

Todd Kuzma
Heron Bicycles
LaSalle, IL
http://www.heronbicycles.com/
oh geez...gtx
Dec 17, 2002 10:03 PM
just read your post--you said what I said below but your response was more detailed and you also beat me to it! ;)
Yes and no.djg
Dec 18, 2002 6:55 AM
I think that points 1, 2, and 3 are reasonable; and the point about weight is likely just true in those cases where a plug-in set of stays allows no design changes in the frame, other than those needed to secure the joint between the CF construction and the seat cluster/upper stay or whatever it plugs into.

I happen to ride a bike with CF stays and I'm disinclined to jump to general conclusions about their merit precisely because it's hard for me to tease out all the variables. I'm inclined to doubt that plugging in a prefab set of seat stays is any sort of magic bullet for frame design. On the other hand, having ridden quite a few bikes, I feel pretty comfortable saying that I haven't liked anything as well as I like my Colnago CT1, which has a titanium main triangle and CF stays (chain and seat). I don't know the extent to which the CF stays contribute to what I like about the bike (I have not ridden, and cannot ride--because it's not available--the identical bike with ti stays), but I do know that there are some excellent hybrid material designs out there. No doubt there are bad ones too, not to mention plenty in the middle.
I respect builders opinionsTig
Dec 18, 2002 7:35 AM
It seems that US builders are dividing into two groups: the latest, greatest tubing, materials, etc., and the tried and true silver brazed steel lug guys. Both have many highly respected individuals whose opinions I respect, as do others. I love an efficient, high performance race frame for fast club rides and races, yet I'll never turn my back on the incredible ride and beauty of classic steel. In other words, I like having BOTH, but for different reasons and uses. We can all agree that no one bike design will work for everyone.

#1 -Sorry about the assumption, but after reading the same negative comments from some who have no experience on the subject each time it comes up, I like to cut to the chase and weed out the uninformed. It gets old. An hour or two isn't enough to form a complete opinion.

#2 -I've said in the past the same thing. I'd love to do a blind test on an exact same bike configuration and frame with different seat stays. The Ciocc EOM and EOM Carbon would be a nice pair of test beds.
I moved 90% of my parts from my old bike to my new one and the improvement is unfair to the old one (but the old frame was truly harsh). Merckx geometry is a wonderful benefit too.

#3 -I agree about how expectations can alter perceptions. A new anything just HAS to be better then the old, right?! It can help people justify the expense. As a human, I'm subject to the same like anyone else. I'm glad I have the patience to let the data come in and not rush to meet it when it comes to a bike or component change. Eventually the truth filters past the expectations. Having the good fortune to own many different bikes over many years has helped build an informed database.

#4 -Ride quality is subjective AND objective. The best objective, mechanical way to test it in regards to CF vs. other seat stays would be to measure and graph the vibrations at the seat post that are transmitted from a rear wheel on duplicate tests. The blind test would be the best human based objective test method.
The weight difference is still minimal. 100-150 grams is only around 1/4 pound, which is only about .14 percent of the total bike and rider weight of a 160-pound person (180 lbs total). If that small weight gain helps improve the rideability of a frame, then it is worth the minor penalty. This is in comparison to aluminum stays, not the heavier steel or Ti stays (of equal strength for stiffness, of course).

I don't think builders should charge so much for the CF stays though. The money they save in fabrication time obviously isn't accounted for. CF-stayed bikes are not outselling everything out there. For some builders (followers), using them is just a way of keeping up with the competition and is just a marketing gimmick. For others (leaders), it opens the doors of design a little wider than before.
Have You Considered Warranty Impact?merckxman
Dec 17, 2002 5:47 PM
I was reading a Pinarello Guarantee CAREFULLY. Pinarello guarantees "that their products are free from defects .....for 24 months, 12 months for the carbon parts." Strange, yes?
highly biased and undefendable opinionDaveG
Dec 17, 2002 6:13 PM
First, let me say I have not ridden one of these frames, so my opinion carries little weight; however, I am highly skeptical of this technology. And, I have to ask myself, if carbon has such magical properties on the stays, why not just build an all-carbon bike? It just seems like another potential failure point to me. I can almost buy some of the hype with Al frames. What really confuses me are STEEL frames with carbon stays - huh? I thought the reason us dinosaurs (me at least) were still riding steel was for comfort. I think what we really need is a super-compact frame with a non-standard integrated headset, carbon seatstays, helium filled tubes, 11 speed drivetrain, and "high Power" chainstays. That would be the ticket. I think the tremendous engineering improvements in bike design and fabrication in the 80's and 90's has been replaced with marketing design and (complete) fabrication.
They workteoteoteo
Dec 17, 2002 6:51 PM
I work in a shop...have for years. Probably just like Todd. The only difference is that I know they work. Why? Because I owned one.

I was a skeptic, just like most shop rats. But after riding I became more and more impressed. That being said the point is mute if the carbon stay is attached to a turd of frame or vice-versa.
how do you know for sure?gtx
Dec 17, 2002 8:49 PM
I think the only way you cold make that claim is if you had ridden two otherwise identical bikes--same exact geometry, build up, tire inflation, etc. You'd also want to make it a blind test--make sure they were both painted the same, so you wouldn't actually know which bikes had the carbon stays before you rode it.
whats all this about more failure points?collinsc
Dec 17, 2002 7:12 PM
by this logic, LOOK frames and OCLVs have even more failure points being that they are aluminum lugs and carbon tubes. ive never heard someone use the 'more failure point' argument against these frames.

whats the rub here? how can one be terrible and another not?
I'm not familiar with the LOOK frames you speak of but..joekm
Dec 18, 2002 6:22 AM
If only the lugs are aluminum and they've sufficiently dealt with interaction issues between the two materials, then fatigue failure won't be as much of an issue with that design.

Speaking as a structural engineer, the real concern would be is you had an aluminum frame with carbon seat stays. If the compliance of the two materials are sufficiently different, it could subject the aluminum to more rapid fatigue cracking at critical stress points. However, there are a lot of factors that drive this and it would be incorrect to automatically assume that such a thing is inevitable.

I would be most concerned about manufacturers that add carbon seat/chain stays just for the sake of having them (ie - chasing a fad). Personally, I'm a little puzzled by Jamis taking their 853 bike and making the rear all carbon. I would guess that their weight savings are more driven by going from Ultegra to Dura-Ace than the carbon rear. Also, if they are going to make such a severe alteration on the ride character of the bike, why not just make the front triangle out of scandium and save a little more weight?

...but then, I'm no expert on bicycle frames. Someday, I'm going to start doing some FEA modeling and see if I can't figure what drives a good frame design.
re: Opinion on carbon seat stays?ASiegel993
Dec 17, 2002 8:31 PM
I can't imagine they're entirely worthless. Just look at Fondriest. They make 2 bikes, the Top Level and Carb Level that are IDENTICAL, except the Carb Level has carbon seatstays whereas the Top Level has curved aluminum stays. The Carb Level is stiffer, lighter and smoother. Why else would Lampre have ridden those almost exclusively last year? Granted, they had a few specially built Top Levels for Paris-Roubaix and the such where they needed a longer wheelbase, but the Top Level was rarely used in comparison to the Carb Level. I'm not going to bother talking about the Don Racer, since that's rather different. So no, I don't think carbon stays are entirely worthless. I think they're just another part of the frame equation. They may be overpriced for their advantages, but they have advantages nonetheless. It makes little difference to me, since I just ordered a Pegoretti Fina Estampa earlier this afternoon, which doesn't have curved or carbon stays, but that bike is good enough in other aspects of its frame to be more comfortable than the grand majority of aluminum bikes i've ridden, including Cannondales. So basically, seatstay technology does not override the rest of the frame being of a higher quality.
-Siegel
-Siegel
re: Opinion on carbon seat stays?ASiegel993
Dec 17, 2002 8:32 PM
I can't imagine they're entirely worthless. Just look at Fondriest. They make 2 bikes, the Top Level and Carb Level that are IDENTICAL, except the Carb Level has carbon seatstays whereas the Top Level has curved aluminum stays. The Carb Level is stiffer, lighter and smoother. Why else would Lampre have ridden those almost exclusively last year? Granted, they had a few specially built Top Levels for Paris-Roubaix and the such where they needed a longer wheelbase, but the Top Level was rarely used in comparison to the Carb Level. I'm not going to bother talking about the Don Racer, since that's rather different. So no, I don't think carbon stays are entirely worthless. I think they're just another part of the frame equation. They may be overpriced for their advantages, but they have advantages nonetheless. It makes little difference to me, since I just ordered a Pegoretti Fina Estampa earlier this afternoon, which doesn't have curved or carbon stays, but that bike is good enough in other aspects of its frame to be more comfortable than the grand majority of aluminum bikes i've ridden, including Cannondales. So basically, seatstay technology does not override the rest of the frame being of a higher quality.
-Siegel
re: Opinion on carbon seat stays?Heron Todd
Dec 17, 2002 8:46 PM
>I can't imagine they're entirely worthless. Just look at Fondriest. They make 2 bikes, the Top Level and Carb Level that are IDENTICAL, except the Carb Level has carbon seatstays whereas the Top Level has curved aluminum stays. The Carb Level is stiffer, lighter and smoother.

How do you know that the Carb Level is stiffer, lighter, and smoother?

>Why else would Lampre have ridden those almost exclusively last year?

Really? Because that is what they were paid to ride. Obviously, Fondriest wants to promote the more expensive bike.

Todd Kuzma
Heron Bicycles
LaSalle, IL
http://www.heronbicycles.com/
SAVE YOUR MONEY YA GOOBS AND.....REPO42
Dec 17, 2002 10:45 PM
Go out and get a crabon seatpost, and fork... keep the frame one piece whether carbon, steel, or aluminum.. If it takes this many people to debate this, then lets face the fact that the quality of ride improvement is minimal, especially for the dollar value.. Ya want a bike that rides all day, then get a Ti frame.. Ya wanna race and want quick acceleration, then get aluminum...If you want an all around bike then go with carbon, and if you want to break the bank on some marketing hype then buy a frame with CF seatstays Einstein....good luck
Aluminum bikes...Breakfast
Dec 17, 2002 10:42 PM
...are great for racers and anybody who buys a new frame every two years. It's really tough to beat an all aluminum frame for the ultimate lightest weight but the lightest aluminum frame has to have the shortest life expectancy, too.

Adding carbon stays to aluminum frames is cool for this group of riders replacing frames every two years but you add some weight and shorten the life of the frame due to the added bonding/attachment points on the rear triangle.

I noticed the number of bikes sporting carbon stays, so I think it's a good thing that the industry has created some excitement and people are buying them. Me, I just don't see the point of buying one. If you want carbon get the whole thing, and it will last longer than the aluminum.
Generalisation?Eager Beagle
Dec 18, 2002 8:11 AM
There are a range of different bonding/construction methods on the market - some seem to be more sensible than others on the longevity stakes.

I think build method/quality is the key in this area - there is nothing inherent in CF that means it will fail in 2 years - it largely depends on the design.
Aluminum bikes, two years?motta
Dec 18, 2002 6:06 PM
Where does this idea of a two year life span on an alu frame come from? For that matter any length life span? I had a alu mt bike for 7 years and it never had a problem, and it was bonded. My current alu road is going on 5 years and shows no sign of this fatigue life everyone speaks of. The supposed short life span of alu is way over blown and should not be factor in the decision to buy or not to buy one. If it is such a poor and brittle material for use on bikes why are bars, stems, rims and components made of it?
Got them. Look nice. No difference.Eager Beagle
Dec 18, 2002 2:49 AM
Rode the exact same set-up Al bike with and without the carbon stays before I got one.

No difference I could notice. Looks nice though, was different, so got one.

Tyres and saddle make a difference way before carbon stays do IMO.

It's a fad - cycling is all about those. But as they go, it a nice one, so why not?
they do make rear triangle stiffercyclopathic
Dec 18, 2002 7:36 AM
and lighter on steel frames.

Ride quality? Not sure. Got Ti frame with carbon seatstays and Carbon seatpost and while I've logged a couple thousand mi on it last summer, I haven't ridden this frame w/o carbon rear so no baseline to compare to. Ride isn't as plush as 525 steel frame, still carbon seems to dampen down high frequency road hiss as good if not better.
Stiffer by design?Jowan
Dec 18, 2002 7:45 AM
My post seem to raise quite a stirr.

Regarding the acclaimed stiffnes of the CF stays, it seems to me that this has more to do with the design than the material itself. Almost all CF stays I've seen are some sort of mono-stay design where most all alu/steel/ti frames have a bi-tubular design. Put a alu/steel/ti monostay on an all alu/steel/ti frame and it also improves the stiffnes.

As for comfort, all full-carbon frames are known to be comfortable, so I can imagine that a carbon sst offers more comfort.

Any visions on this point of view?

Regs,

Jowan
That's interesting...eyebob
Dec 18, 2002 8:10 AM
The idea that the stiffness is (at least in part) attributed to the mono-stay vs. the bi-tubular design is intriguing. Are there any steel or Ti(I know that there are CF)frames that have a steel or Ti mono-stay? If so, how "stiff" are these?

BT
That's interesting...geeker
Dec 18, 2002 3:50 PM
Mondonico definitely has steel frames with monostays (see www.torelli.com). Think there are others, but no names come to mind. Haven't ridden any, so can't comment on relative stiffness. But from the engineering standpoint, the rear triangle is already totally rigid, so I doubt very much that monostays "ride any different" than bistays. They *do* look cool, though.
re: Opinion on carbon seat stays?Lactate Junkie
Dec 18, 2002 11:01 AM
90% Fashion--10% function, No wait a minute 99% Fashion--1% function.

Also stays and forks are the most difficult and expensive part of a bike to build. If you can buy a seat stay/chainstay combination and a fork out of carbon for $50 in Taiwan and just glue it into a front triangle it is very cost effective when you are retailing the frame for $2500. Come to think of it, just have the aluminum front triangle welded up in Taiwan as well, ship it to Italy, paint it and call it an "Italian Dream Machine" . Ha the consumers will never know the difference.
Test Casecogmaster
Dec 18, 2002 7:21 PM
I ordered a custom Ti frame with carbon stays(to receive tomorrow and will build up and test ride this weekend). I currently have an all ti bike and will let you folks know if there is any noticable difference. It cost me about $250 more for the carbon stays. Weight saving from my builder was reported to be 1/3 of a pound. Other supposed benefit was that rear end is supposed to stay in better contact to road in turns due to less deflection. Cannot comment if this is real or marketing BS.
GOT SOME NICE SWAMPLAND TO SELL YA ......REPO42
Dec 18, 2002 10:54 PM
Maybe is there is a difference, but as I stated in an above post. Does the benefit one gets from the CF stays warrant spending an extra 250? I ask anyone who is an owner to answer this. Does using the CF stays make your average speed any faster....If the answer is no, then I surely can find somewhere else to invest $250 that can improve comfort or performance.. If you are into a soft riding bike then go out and get a TI frame...