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Cipo's long lost cousin
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Discussion Starter · #1 ·
I have recently seen picts of a couple of carbon fiber forks that use carbon dropouts (example - 2004 C-Dale Slice fork). Maybe it's just me but does that seem like a good idea?

Bear with me now as I am not a material scientist or mechanical engineer...

From my basic understanding of composites, carbon fiber is simply layers of carbon (typically woven) with some type of epoxy filler used to "cement" it all together. For a long time there has been issues about scratching carbon fiber components which could cause the component to fail. Examples of this concern include handlebar mfrs limiting the use of tri-bars and bar-ends on carbon handlebars.

Is the carbon fiber/filler now more "scratch resistant" that it could withstand serrated quick releases and hubs? Any industry types want to chime in on this one?
 

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Banned forever.....or not
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One of my bikes has a fork with all carbon tips. I'm very careful with it, to make sure that I don't clamp down too hard w/ the QR.
Not the best idea, in my opinion.
 

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Just put it this way...

... this is not something that I would like to test. May not be long before the entire bike is carbon fiber, but I'd rather critical components be thoroughly debugged by others first. I think carbon makes great tubing-type components, but it's weakness seems to be where it attaches to other parts -- like where the hub attaches to the fork. It's practically impossible to crush solid metal and metal is much more abrasion resistant -- problems with carbon fiber. There are carbon chainrings out, but I think their estimate life is something like 500 miles; that should tell you something.

Doug
 

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As cyclists, we worry too much about carbon

I think we worry too much about the strength of carbon fiber. The yachting and automotive industries have been using carbon for years. Look at this website. This boat is 140 feet long and the entire hull is a made of carbon fiber. Both 145 foot masts are made of carbon. I used to race large boats in another life and I can assure you the loads placed on a boat like this are tremendous..

http://www.mari-cha4.com/pub/frameset.php
 

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good examples of what carbon does best

Dave Hickey said:
I think we worry too much about the strength of carbon fiber. The yachting and automotive industries have been using carbon for years. Look at this website. This boat is 140 feet long and the entire hull is a made of carbon fiber. Both 145 foot masts are made of carbon. I used to race large boats in another life and I can assure you the loads placed on a boat like this are tremendous..

http://www.mari-cha4.com/pub/frameset.php
Those are great examples of what carbon does best, tubing and sheeting applications. I worry more about little parts and when carbon interfaces with something else, especially metal. I have perfect confidence in carbon frames, and almost perfect confidence in carbon forks, cranks, handlebars, and seatposts. Dropouts, chainrings, stems, derailleurs (had a Record 10 carbon rear derailleur explode on me), not so much.
 

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DougSloan said:
Those are great examples of what carbon does best, tubing and sheeting applications. I worry more about little parts and when carbon interfaces with something else, especially metal. I have perfect confidence in carbon frames, and almost perfect confidence in carbon forks, cranks, handlebars, and seatposts. Dropouts, chainrings, stems, derailleurs (had a Record 10 carbon rear derailleur explode on me), not so much.
I agree that some applications aren't good. I think carbon chainrings and screws are crazy. I might be willing to use carbon dropouts depending on design. What I don't want to be is a guinea pig for carbon experiments. Part of the problem I see with carbons popularity is too many manufacturers are trying it and they might not have the experience in working with it.
 

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Cipo's long lost cousin
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Discussion Starter · #8 ·
Good points...

It seems that there are some applications where carbon fiber is better suited then others.

In the case of a fork dropouts the hardness of the material and its reaction to sheer forces concern me... Aluminum, Ti, or steel makes nice hard surface to clamp your hub; but what about carbon fibers with a filler/epoxy material? Thats why the example of bar-ends or areo bars comes to mind... If I were to take a screwdriver and scratch downtube of a Trek 5500 I would worry it would sheer. How can a carbon dropout withstand the scratching and clamping forces applied with todays hubs and QR skewers?

It just seems like a risky way to save some weight...

Steve-O (Maybe I'll copy Easton or Reynolds on this thread)
 

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I love my Fondriest
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Dave Hickey said:
I think we worry too much about the strength of carbon fiber. The yachting and automotive industries have been using carbon for years. Look at this website. This boat is 140 feet long and the entire hull is a made of carbon fiber. Both 145 foot masts are made of carbon. I used to race large boats in another life and I can assure you the loads placed on a boat like this are tremendous..

http://www.mari-cha4.com/pub/frameset.php
I seem to remember the America's Cup, NZ vs Allingi. Good-bye mast as it snapped on Team NZ's black boat. Oh the horror, loosing to the Swiss...
Having said that, I just got a Fondriest Carbon Magister, and am thoroughly impressed after a short 8km ride. I can't complain about it, apart from the chain dropping twice in the first 100m, causing part of the clear coat to be scratched under the chain stay :(
In regards to dropouts; the Fondriest Top Carbon TF1 has rear drop outs in carbon, with alloy reinforcement plates. The forks on my Magister are the Top Carb ones, and are alloy dropouts
Maybe it's best to just wait and see, I know I wouldn't use them though.
 

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Miggity Mac Daddy
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I'm not sure, but I'm guessing...

That it isn't all carbon fiber. I am thinking that there is a little aluminum plate in there to give it some structural/compression strength - just theorizing.
 

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Kiwi Rider said:
I seem to remember the America's Cup, NZ vs Allingi. Good-bye mast as it snapped on Team NZ's black boat. Oh the horror, loosing to the Swiss...
Having said that, I just got a Fondriest Carbon Magister, and am thoroughly impressed after a short 8km ride. I can't complain about it, apart from the chain dropping twice in the first 100m, causing part of the clear coat to be scratched under the chain stay :(
In regards to dropouts; the Fondriest Top Carbon TF1 has rear drop outs in carbon, with alloy reinforcement plates. The forks on my Magister are the Top Carb ones, and are alloy dropouts
Maybe it's best to just wait and see, I know I wouldn't use them though.
Your right about NZ losing a mast but that was a mechanical failure that caused the mast to break. An alumunum mast would have gone also.

FYI, I'm with you.... I didn't want the Swiss to win either. There is something wrong about a land locked country winning the America's Cup
 

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As wrong as...

Dave Hickey said:
Your right about NZ losing a mast but that was a mechanical failure that caused the mast to break. An alumunum mast would have gone also.

FYI, I'm with you.... I didn't want the Swiss to win either. There is something wrong about a land locked country winning the America's Cup

About as wrong, or worse than, a non-european winning a Grand Tour? ;-)
 

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The Edge
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On the boats I used to row on, we would have bolts going through the equivalent of an all carbon dropout to mount our riggors (the structure the attaches the oar pivot to the boat). The important thing was that the bolts closely fit the ID of the hole and that washers were used on both sides so that niether the nut of the bolt head could dig into the matrix. Some of our boats are 8 years old with the equivalent of 3000 miles a year put on them and we've never had a failure at the riggor mounts.

I guess if you are nervous, just put some aluminum washers on your QR, but don't be surprised if you have to really clamp down hard to keep the hub from moving in the drop outs.
 

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Arrogant roadie.....
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How much do you value your @$$?

Because, if it breaks while you're going 40 mph, that's what's gonna get whupped!!
 
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