I have no problem opening this box of worms: I like this discussion, and this is what I'm doing about it:

1. I bought four new bikes for the '03 season. One, a Yaqui Carbo, has carbon fiber seat stay assembly. The others do not. I will publish my impression and opinions (this is not a pragmatic, empiracle test- I don't have that capability and I'm not an engineer) on our website.

2. I have finished the review of the Litespeed Saber with a carbon seat stay assembly and have substatial commentary on it in that review. It will be up soon.... (on bikesportmichigan.com).

3. I have heard several sides to the arguements for and against. I have already ridden a lot of bikes with both that were properly fitted. I think I am formulating an opinion, but hesitate to comment yet as I still want to gather more information and impressions.

So, much more to be said. What are your opinions/expereinces?

---

Tom Demerly
The Tri Shop.com

I'm seriously considering the Carbo...I wait with bated breath for this information.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

For a comprehensive overview of materials and combinations of disimillar materials Craig Calfee, Calfeedesign.com has a thorough white paper write up. Granted Calfee only builds all carbon bikes, but he does do a good job of explaining material pros and cons.

To sum it up, he feels that mixing of materials is not a good idea unless absolutley nessecary (ie bottom bracket shell, rear drop outs etc.) The oxidation between the materials and adhesives may have a tendancy to break down the connection.

Check it out it is a good read for the "reading room".

Just to add to the above post, Craig Calfee does an exceptional ammount of research and testing on his own, so his findings are not to be taken lightly, and are based on actual empirical data, not just guesses or assumptions.

tommy

Carbon seat stays are a great way to take a bike that should last a lifetime - and put a term on its life. I think that it is a shame that we are taking great Titanium and Steel bikes - tossing in some Carbon, dropping lifetime warranties for 1-5 year warranties and calling that "improvement".

---

----------------------------------------------------------

What if the Hokey Pokey is what it is all about?

This is an interesting observation and perspective. Point taken. Hmmmm. More research ongoing....

---

Tom Demerly
The Tri Shop.com

If you notice, my signature says "Just say NO to Frankenbikes and Integrated Headsets!!!". What's a "Frankenbike"? A bike with materials joined to it that DON'T belong together.

Yes, aluminum headtubes, BB shells, and dropouts are bonded together. But this is done in accordance to the rule of using fibreglass to insulate from galvanic corrosion. Where did this come from? The old days of Frankenbikes (ala Specialized, Giant, and others). They all learned that the carbon MUST be insulated from the aluminum, or the two will become what is essentially a half-volt battery.

I would have thought that the modern Frankenbike makers would have included this. But when I was looking in the frame maker's catalogue, I found nothing in the literature about these Franken-stays that provide for the insulation of these materials. Also, the geometry is "movable", meaning that you can have one stay fit many bikes. The lug can be manipulated in many ways, meaning that the glue fills the gap. From my understanding, the gap must be of a very specific measurement for gluing. Maybe the gap would be including the amount of fibreglass. Maybe the glue had glass microballoons. Who knows?

Maybe all of these things have been addressed. But I have not gotten enough satisfactory answers to make me change my mind and my signature. So, let me say it again: JUST SAY NO TO FRANKENBIKES!!!! They suck and they could compromise the safety of your bicycle!!!!!!

Ahhhhh...only b/c I am feeling ornery...I am very much looking forward to my integrated headset sporting, carbon seatstay having, clincher tire rolling Saber arrive very soon now.

So there. ;-)

Now, since I am the wise guy you may lecture me at will I guess...

(Hey - at least I'm getting a Renn!)

---

---

"To give less than your best is to sacrifice the gift." - Pre

MattMizenko.com

glad you cleared that up, bunnyman. i have always kinda wondered what the hell you were talking about. . . . .:)

btw, i had a spec. carbon allez that did just what you mentioned. the thing looked the top of a car battery, with dried white foam/scum oozing down the tubes. spec did give me a new s-works m4 for it tho, which i hated and gave away to a friend. just say no, indeed.

Its a bit disingenuous to assume that today's bike designers don't know all about galvanic corrosion and how to prevent it. Maybe some of the small-time makers don't but it'd be a stretch to think Litespeed and others haven't addressed that issue.

Well, you should ask Gerard about whether or not any of the bike manufacturers know about this stuff or even worry. I heard it from him (amongst others), and I got my confirmation by asking questions.

I wouldn't worry about the Ti and carbon without insulation, as it's not so much of an issue with ti and carbon or steel and carbon.

Hey- it's up to the consumer. I am just stating my opinions, sir.

Ti and carbon is not a problem (generally). My only problem with Litespeed is that they call it "Ti enhanced carbon" when the only Ti in the stay is a sticker containing titanium dioxide to make it look like it's ti.

Clinchers are okay to train on, just not race.

All of these criticisms aside, you're still getting a mighty sweet bike.

I have personally seen enough of these bikes with battery acid-looking things going on. I just don't like history repeating itself.

What scares me about the Frankenbikes is that I thought that maybe people remembered this stuff and were insulating the carbon from the aluminum. But according to enough respected people it is the exception rather than the rule. That is sad, for certain.

Just say NO!!!!!

If I understand you correctly (I am Swiss German speaker) you don't suggest to use a carbon seat post on a aluminium bike because of galvanic corrosion. Or is a seat post not the same as a seat stay? Can I use a carbon seat post on a aluminium bike.

In the thread 'Carbon seatposts' http://www.slowtwitch.com/cgi-bin/gforum.cgi?post=2906& from begin of January nobody said something about galvanic corrosion. Therefore I probably mix up something because my 'medium' english knowledge (I like the 'Check Spelling' button when posting).

I ask this because I am considering buying a Corima Ellipse carbon seat post for my Cervelo One. I would buy it mainly because it looks cool and is ligther (and I read that they are more comfortable)

Felix, Switzerland

Felix,



I would not worry. The carbon post is clear coated, and you will have a thin layer of grease on the post. Though a reaction is possible and will happen given enough time, normal maintainance will prevent this from being an issue for you. One of the most often seen issues is an Aluminum post - stuck in an Al bike. If the owners of these stuck posts would remove and lube them every few months or so, there would be no issues.

---

----------------------------------------------------------

What if the Hokey Pokey is what it is all about?

At the Corima website I read that you should remove the seat post at least once a year. Now I know why. Thanks!

The rear seat stays on a bicycle typically see 6 or 7 cut, mitered and welded, bonded, or brazed joints. With the carbon stays, there is 1 joint that is cut and welded. 99% of these assemblies are "one size fits all" and come furnished with bolt on dropouts. Now if I were John Q. Frame builder in Taiwan and I could cut different stays for every bicycle size I build, align the seat stay bridge for the rear brake, and attach them to a drop out and have a homogeneous frame, OR, cut and miter a monostay, weld it, and tighten two screws on the dropouts for EVERY size bike I made, call it "enhanced" and charge more, I'd jump at the chance. With regards to the vibration damping, what keeps the vibration from traveling along the chainstays and up the seat tube? Does a bell with a hole in it still ring? Sure the hole doesn't vibrate, but you can bet the rest of the bell still does. Buy a carbon seat post, it isolates the frame from your bum with carbon.

---

https://www.kickstarter.com/...bike-for-the-new-era

"They all learned that the carbon MUST be insulated from the aluminum, or the two will become what is essentially a half-volt battery. "



Probably a bit more than 1/2 a volt... A few wires - some salty wet roads - and you can probably run your cycle lights off them :-) Bargain!

I bought a new Olmo last summer, with Carbon seat stays. I love the bike. I get enough stability in the compact (& small) Al frame with the flex in the carbon seat stays, front fork and seat post. It's a good middle point for me. My only concern is that I was not told, when buying the frame, that riding in not so good weather over time (i.e.: fenders in the winter - I live in Vancouver BC so our winters are basically extended springs -lots of rain little to no snow) might cause them to wear through/corrode out. Anyways, I think that depending on what you do with your bike, how you like to ride/race, go with whatever works for you. For me, this set-up works better than anything else I tried.

---

------------------------
"How bad could it be?" - SimpleS