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ti/carbon mix--unclear on the concept(22 posts)

ti/carbon mix--unclear on the conceptgtx
Nov 19, 2001 3:17 PM
I can understand why you'd maybe want carbon stays on an AL frame. But carbon stays on a ti frame (Seven, Colnago, now Airborne, etc.) seems kinda silly to me--if you want comfort, a good ti builder should be able to build in any level of comfort you might want, and if you want light weight, why not go all carbon (C40, Calfee, OCLV, etc.)? So then Serotta comes along with their take on the subject.

http://www.serotta.com/pages/ottrott.html

Thoughts?
re: ti/carbon mix--unclear on the conceptbikerduder
Nov 19, 2001 3:34 PM
I'm not sure what Serotta's reason for building this is?? Seems like if comfort was the goal, they would have used carbon in the seat tube or stays, not in the top/down tubes. I haven't decided wheather the carbon/aluminum or carbon/ti is a fad or not. From the reviews I've read on some of the bikes out there, it has a negligable effect on comfort anyway. Having ridden a carbon frame for 4 years, I can testify to the comfort and weight savings on an all carbon frame, but isn't Ti supposed to be just as comfortable?
dampeningDog
Nov 19, 2001 3:37 PM
From what I've read, and experienced a little, carbon dampens vibration better than metals; plus, it can be made very stiff; these qualities help to stiffen the rear triangle, while at the same time dampening vibration a little -- a good thing for either aluminum or titanium bikes.

Doug
dampeningbikerduder
Nov 19, 2001 3:49 PM
Dog - I hear what you're saying, but did you look at the Serotta site? It looks like they only used the carbon for the top/down tube, which is why I can't figure it out.
hmmDog
Nov 19, 2001 3:54 PM
A friend's Odonata I saw had a carbon seat tube and seat stays. I'll look again.

Doug
Oh, the OtrottDog
Nov 19, 2001 3:57 PM
That one is over my head. I don't get it. Why not just make a carbon bike? I'll read their explanation, but I'm sure it's simple self-serving marketing b.s.

Doug
Does Serotta B.S.?kenyee
Nov 19, 2001 6:02 PM
I've always gotten the sense that they deserve the reputation they've earned from all the people who have ridden it?
Wish I could find a used CSI to satisfy my curiosity ;-)
dampeninggtx
Nov 19, 2001 4:02 PM
yes, but you can get whatever level of dampening you want out of ti stays, too. Moots and others base their softail concept on this--you can get really cushy stays out of ti. Ti Cycles gets over 2" of travel out of their normal, round chainstays--this is flex only, no pivot!!!

http://www.ticycles.com/98/mtn/24-kgp.html

If anything, you might almost use carbon to stiffen up the rear of a ti frame, while maybe achieving some minor weight savings. But that doesn't seem to be what Seven is going for. And the bike obviously won't be as crashworthy (which may not be an issue to someone dropping $3k on a frame).

So then there's the Serotta--are they going for a stiffer, lighter front triangle? That might work, but it seems like there would be long term durability issues with this kind of design. Why not just use oversize ti tubing for the front triangle?

Like I said, it seems to make sense to use carbon stays with AL, but not with ti.
oops, I confused Seven and SerottaDog
Nov 19, 2001 4:13 PM
Now I see why I could not find the Odonata on the Serotta site. Duh.

I still don't get using carbon top and down tubes on a ti bike.

Doug
Marketing BSJon
Nov 19, 2001 4:51 PM
Due to the lack of any real innovative ideas the bike industry has tried to create some
novelty by marrying carbon fibre with other materials in all sorts of non-functional
variations. Remember the old adage? "Bullshit baffles brains."
I agreeNessism
Nov 20, 2001 7:13 AM
Alot of people will buy something just because it looks cool. The carbon stay frames fall into this catagory in my mind. It may change the feel a little, but overall the functional advantage is next to nill. How much $$ is feel worth?

All things considered, I guess there are worse ways to spend money.
Damping?Kerry Irons
Nov 19, 2001 5:06 PM
I'd rather damp the vibrations and stay dry. Dampening happens often enough this time of year (around here anyway) regardless of the frame material you use. Damping vibration = good. Dampening = getting wet = bad.
Dumping?GIVE HIM A BREAK
Nov 20, 2001 5:11 AM
nm
Damping?Dog
Nov 20, 2001 6:34 AM
see below:

"The original reason Seven elected to use carbon in the seat stays of the Odonata was to balance out the ride characteristics that a carbon fork brings to a bike. By using carbon in the seat stays, we discovered a level of dampening similar to that of a carbon fork. In other words, we realized good dampening in the front end and the rear end, while maintaining many of the great ride characteristics of titanium (or steel), such as liveliness (which carbon traditionally does not offer) and durability (which carbon does not offer)."

Check some dictionaries, too. Very close meanings, if not interchangeable.

Doug
Kerry's right,TJeanloz
Nov 20, 2001 11:13 AM
This is one of my boss's biggest pet peeves- in reference to bicycle shock absorption it is damping, not dampening.
I knowDog
Nov 20, 2001 11:22 AM
He's right, but apparently common (mis?)usage has made them nearly identical in meaning, according to the sources I read.

Doug
Here's Seven's explanation...MikeC
Nov 19, 2001 5:08 PM
It obviously has a marketing angle, but at least they TRY to explain it:

Understanding the Seven Odonata

10 September, 2001

In addition to being the first of its kind, the Seven Odonata, our 3.25 butted titanium-filament wound carbon road frame, has excellent dampening characteristics, making for a super-comfortable ride that's not too soft or flexible. At the same time, it is extremely lightweight, yet maintains an amazingly stiff drivetrain for maximum efficiency, especially while climbing and accelerating.

The Odonata's wonderful ride is no accident. Seven's Rob Vandermark spent years working with carbon, developing and testing prototypes, before he came up with the Odonata design.

The Rationale Behind Our Design
The Odonata utilizes filament wound carbon in the least stressed areas of the frame, the seat tube and seat stays. For one, these tubes are under compressive stress, alone, and two, the tubes most likely to bear the brunt of impact or abrasion damage during a crash are the top tube, down tube, and chain stays. We incorporate carbon in the Odonata's seat tube and seat stays purposely to avoid these high-stress areas.

Filament Wound Carbon Seat Stays
The original reason Seven elected to use carbon in the seat stays of the Odonata was to balance out the ride characteristics that a carbon fork brings to a bike. By using carbon in the seat stays, we discovered a level of dampening similar to that of a carbon fork. In other words, we realized good dampening in the front end and the rear end, while maintaining many of the great ride characteristics of titanium (or steel), such as liveliness (which carbon traditionally does not offer) and durability (which carbon does not offer).

Filament Wound Carbon Seat Tube
As mentioned earlier, the seat tube is well protected if you lay your bike down. In addition, the seat tube, along with the seat stays, contributes to rear end dampening.

Our Carbon History
Rob Vandermark actually began looking at the combination of titanium and carbon more than 12 years ago, back in 1989. At that time, he was responsible for the design and fabrication of two important projects:

1. A full carbon frame, including carbon seat and chain stays, that incorporated titanium lugs into its design
2. A frame consisting of a carbon front end, a titanium rear-end (seat and chain stays), titanium head tube, and titanium lugs
It is important to note that these particular projects did not come to fruition because of their poor durability stemming from the impact resistance problem.

Seven's Prototypes
Early '97 saw the development of the original Odonata titanium prototype. We are pleased to report that despite the rigors of repeated testing and harsh riding, it is still being ridden today.

At the same time, we also created a prototype titanium mountain frame sporting a carbon seat tube. That frame (and design) was discarded because of the potential for crash damage. Nevertheless, that bike, too, is still being ridden.

In addition, we created four more prototypes of varying designs to test the limits of our design ideas. Here's what they were-and what we discovered about them:

1. A titanium-carbon road frame with carbon seat stays, seat tube, down tube, and top tube. This frame was retired because of the rather lifeless ride characteristics created by its carbon main triangle.

This Odonata prototype, featuring a carbon main triangle, has been retired. Its ride characteristics were repeatedly described by testers as "lifeless."

2. A titanium-carbon cyclocross frame with carbon seat and top tubes. This 'cross frame has had three "top tube-ectomies" necessitated by crashes and handlebar damage (bar spun around and smacked the top tube).

The carbon top tube on this Odonata 'cross prototype has been replaced three times.

3. A titanium-carbon road frame with carbon seat stays, seat, and top tubes. The top tube on this frame has been replaced once. The frame continues to be raced.
4. Steel-carbon Odonata prototypes. These frames have never needed repair, and have a great ride, which is why we brought the steel Odonata into production!
With the exception of prototype number one, all of these bikes are still being ridden and raced today, though we overwhelmingly prefer the production version of the Odonata (carbon seat stays and seat tube only) for its excellent ride characteristics and durability.

The winners by a mile!
All of our testing and prototypes led us to conclude that the best application of titanium (or steel) with carbon is to complement the use of a carbon fork by incorporating carbon into the frame's seat stays and seat tube. Frames that use carbon entirely, or anywhere in their front end, tend to exhibit so much dampening in the front end of the bike that the ride feel can only be described as "dead."
Serotta's Reasoningmavic1010
Nov 19, 2001 5:22 PM
Since no one has given serotta's rationale to why they used the CF on the top tube and down tube, I'll try my best in explaing their reasoning.

The most weight savings without dampening the ride of serotta could have only been achieved by replacing the top tube and downtube with CF tubing. At first, I was very skeptical of the design. However, Ben didn't want a CF bike that rode like a CF bike. His benchmark is the CSI which of course gives one of the best steel rides out there. Having test ridden the Ottrot (ben's bike), I must say it doesn't ride like the Legend ti, and it comes close to the CSI's feel. The frame is also incredibly light. So why not put rear carbon stays on the bike? Ben claims it has minimal weight savings and doesn't enhance the ride quality that much...this may only apply to titanium frames.

It may be all a marketing gimmick... I like the bike and I have one on order, so maybe I fell for it. The ride is smooth, the bike looks trick, and I'll ride it for a long time. Just remember that the CF tubes are not these simple round tubes...they are in the same shape as the colorado concept tubing..which may explain why the ride is different from another CF/Ti bike.

BTW, ben has a couple of prototype bikes with rear carbon stays (courtesy of Reynolds). Only difference is that the pivot points where the chain stay and seat stay are exactly the same as the Hors Categorie elastomer design..hence a little more give...we'll see if it ever goes into production.
My theory ...tarwheel
Nov 19, 2001 6:35 PM
Here's my theory, FWIW, which is very little. Carbon has this "reputation" for dampening vibration but I don't think it really dampens as well as steel and possibly not as much as ti. I know my steel bikes dampen rough pavement better than the two carbon bikes I have ridden. (I have never ridden a ti bike, so I can only speculate about its ride.) Carbon, however, is much better at dampening vibration than the other ultra-light alternative -- aluminum. So, I think Serotta mainly added the carbon to their new frame to lighten its weight, while keeping the ti in areas where it would dampen vibration better. Fire at will.
the more I think about it...gtx
Nov 20, 2001 11:21 AM
the more I think Serotta got it right. I think you can dial in more comfort with ti stays. The carbon in the main triangle of the Serotta is there to "look cool" while lightening things up but remaining stiff (still think it would be better to use oversize ti tubing in the main triangle). Carbon stays makes sense with AL frames, but not ti.
From experienceCSIguy
Nov 20, 2001 3:07 PM
I have owned both Seven's all Ti Axiom and their Ti/Carbon Odonata. While both have a smooth, dampened, if you will, ride, the Odonata has the smoother ride of the two. The Odo literally feels as if you are floating over all but the biggest bumps. With a good carbon fork I get an even level of swoosh over rough stuff from both ends of the bike. With the Axiom the front would feel smooth, but the back would kick more up through the stays and into my butt and lower back.
Subtle, but distinctive differences and at this price point that and zoot factor is what it's all about.
Oh...and I still like my lugged steel Serotta CSI best of all! :-)
good info!gtx
Nov 20, 2001 4:12 PM
always good to hear from someone who has actually had some miles on the bikes in question. And yes, go lugged steel!