I posted this on the old forum too. What do you guys think of carbon stays? Some bikes that have them I like, some not. Thoughts?
Galvanic corrosion. Don’t think we’ve seen the last of it.
test drove a LS saber with and without carbon stays for about 10 miles each . couldn’t tell the difference. whether it was real or perceived, the carbon stays felt a touch noodly when i climbed out of the saddle. i ended with purchasing the frame w/o the carbon stays. my two pennies worth…
if cervelo doesnt have it. It must be BAD.
thank god i dont have a tiny bold that holds my seat
Stay away from them. Period. The bond is a thick layer of glue mixed with glass pellets that will do little to stop galvanic corrosion. All a carbon seat stay will do is add more weight and a weak point in the frame. If you want the ride of a carbon bike (or to sell one, as apparently you sell bikes:), get a carbon bike.
Tom,
You own a bike shop and you are asking opinion from people you dont know over the INTERNET, ON A PUBLIC FORUM ??
NO WONDER you been pushing and selling CERVELO bicycles. WHere is your shop again ? ROFL
I have very strong positive feelings about this bike. I really like the carbon stay assembly on this bike. The ride quality (my opinion) may be the best of any triathlon bike. It is excellent. There are other comments in the review (which will post shortly on my store site) that are a bit less gushing, but all in all this bike is an incredible winner, and I think the stays are part of it. It is interesting to see so many people comment about galvanic corrosion, potential failures, etc. We have sold over 60 bicycles of different makes with carbon stays. Zero failures, zero problems. I haven’t even heard of one breaking. so far, I am very, very impressed.
According to a Bianchi rep that I talked to, they carbon stays are just for show and don’t add much of an advantage if any. They adopted them for 2003 just to stay competitive.
Any labtest I’ve seen between identical frames with and without carbon stays shows there is no increase in comfort (vibration absorption, vertical compliance), only an increase in weight (usually around 40g due to the overlaps).
So that leaves looks, comfort perception and the general idea among manufacturers that they “have to stay competitive” with what other manufacturers do. I just don’t get it (ESPECIALLY on a Ti bike), but I’m glad that companies that I respect for their R&D like Cannondale and Principia haven’t joined the trend.
I am seriously considering the purchase of a Cannondale Scapel. It has a carbon rear triangle/chain stays - but I think this is a bit different. They are using the flexibility of carbon to avoid a metal pivot or hinge. I think this makes sense.
definitely a different story. While the same potential problems exist (which also can be fixed), the upside for that application is much bigger. The fact that it is in a chainstay, that the chainstay shape is such that it acts like a leaf spring, that the rear triangle is not rigid like on all those road bikes with carbon rear ends, it makes it work completely different. The Scalpel is a pretty nice bike, I almost bought one last year.
Tom:
There was extensive discussion on the old forum before you started posting. Regarding the bond and galvanic corrosion a couple of points to add.
Although you have sold about 60 bikes, there hasn’t been sufficient time yet for catastrophic failures from galvanic corrosion – but give it 2-3 years. As a retailer, I would think you would be concerned enough about potential liability to question the vendor extensively on this issue.
Also, as I am sure you already know, the strongest adhesive bonds depend on a very tight joint with a thin adhesive layer. The forum previously discussed, although I haven’t looked for myself, that the joints had a huge amount of slop to get the chainstays or seatstays to fit without needing separate part numbers for each frame size. It the fit has several mm of slop filled by adhesive, that is also a failure waiting to happen. You can go look at the joints for yourself; I’d be interested in your observations.
Please understand that I am simply recapping the essence of prior discussions. I am certainly not an expert of this myself. I am sure the experts will jump in and correct any mischaracterizations.
Regarding your information on the “slop” in the fit: One manufacturer assembled a bike with a carbon wishbone seatstay assembly with no glue at all- it was a “press fit” to get a feel for how tight it was. They use “glue channels” inside the joint to control the thickness and location of the adhesive layer. Anyway, they put over 1,000 miles (and counting) on the bike with no adhesive, just the press fit. I was pretty impressed by that. Also, I am no chemist and no engineer, but a dollar to a dime there are a couple out there reading this, so, can titanium and carbon insulated from contact by cyanacrylate (or however you spell it) actually corrode? What about aluminum? I have consulted extensively with manufacturers about the lifespan of these products, and, like the older Trek 2300 aluminum/carbon bikes, the old bonded Vitus 979 Duralinox and carbon bikes, there haven’t been a preponderance of problems.
Tom,
You own a bike shop and you are asking opinion from people you dont know over the INTERNET, ON A PUBLIC FORUM ??
NO WONDER you been pushing and selling CERVELO bicycles. WHere is your shop again ? ROFL
Ummm…so WHAT is your point? There are sh*tloads of pros paying for and rebranding Cervelos to race in piss-ant TTs like the TdF and U.S. Elite TT too…your “statistic” makes no sense. Are they all also part of the “unwashed, misled masses” being brainwashed by Cervelo? And no, I don’t ride a Cervelo, I ride a Cannondale.
Galvanic corrosion is not an issue for carbon-Ti (I think the issue in this case is more that if Ti is so good, why ruin it with carbon stays?). It is howver an issue with Alu/carbon, an issue that can be solved but few manufacturers seem to bother with that hassle.
With the gaps and variable thickness of the bonding, there are different issues. Whether it will hold up over time is an open issue, I think quite a few of the early Treks and Vitus frames developed problems over time, although most of them probably aren’t ridden anymore. People always buy the last bike ever only to buy a new one two years later, so relatively few bikes really get a lot of miles on them. That may be the saving grace for the carbon rear end.
As for the dealers, I would think they have little to fear if these carbon rear ends fall apart, as long as the manufacturer is still in business it is their responsibility. I’m just glad it won’t be mine.
Tom,
A few thoughts…In no particular order…
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I have a friend who got a Colnago CT1 in January 2000. He rides a LOT (12,000 miles per year if you include the windtrainer–He lives in South Bend, Indiana). His bike is still riding strong.
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The whole “how long will it last” argument seems a bit moot. Why? Simply put, when you buy ultralight frames, components, etc. They are designed for racing and have a limited life. I know people don’t want to hear that when they’ve just dropped $4,000 on a bike, but it’s reality. Super thin-walled aluminum or steel aren’t designed to last a lifetime. They have a specific purpose. In short, I think that the “long-term” effects of Galvanic Corrosion should be approached the same way. The guy who is buying a Carbon-stays bike is likely to buy in new bike in less than 4 years anyway.
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There were a TON of bikes with Carbon Stays at Interbike this year…So many that I doubt it creates any competitive (marketing) advantage to have it. In a 2/2, carbon stays have moved from the upper right quadrant (delighter) to the merely competitive quadrant. In short, I’m not sure it’s great marketing any longer.
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I’d rather have a Blade (with Ti stays) than the Sabre…Simply put, I’m not that interested in Carbon Stays because of the extra weight and the PERCEIVED potential for failure.
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Litespeed makes good product. I don’t think you’ll have trouble “selling” the Sabre to riders if it fits them well. However, I don’t think the carbon stays will make a significant impact in their decision (unless you really “play it up” as more comfortable for Long Course…which is obviously quite debateable).
I’m no materials specialist, but I think this galvanic corrosion thing might be a bit overblown. Maybe it’s an issue on fighter jets, but bicycles? My wife has one of those old Treks - the 2300 I think it is. Mixes carbon with aluminum. She’s had it 8 years. Rode it frequently on the trainer in the garage. Loaded it up with sweat and rarely washed it. There’s never been a problem. If it is such a problem, what about carbon seat posts or carbon forks with aluminum steerer tubes and drops?
The galvanic corrosion thing is a legitimate concern. How old is your wife’s 2300 (what colour)? At some point in the production of the 2300, trek started using an insulating material in the joint to protect against gc. Prior to that, many did fail due to the corrosion in the lug.
IMHO, the carbon stay thing is a fad dreamed up by marketing departments. Actually, there is a potential benefit from a quality control point of view, as the one piece carbon rear end simplifies assembly and alignment of the frame.
You can naver have enough carbon posts…
I don’t think it adds to a frame in anyway. I think the Caad8 frame is a good example of well designed Al stays be comfortable, stiff and light. I agree that the co. the do good R&D stay away from rear triangles.