Should i buy a carbon frame

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treetrees
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by treetrees

Yes you are completely right Kgt 2 really good reads from davidalone and effeballi , many thanks guys

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Calnago
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by Calnago

Agreed... Great info and food for thought.
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dmulligan
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by dmulligan

treetrees wrote:Sorry for all the questions I'm just trying to get a feel for what it can and can't do . Thanks everyone for the response it's an absolute pleasure chatting


Don't be sorry. I recently bought my first CF bike and had all of the same questions and follow up questions. I wish this thread had existed last summer as it would have made my decision much easier. I love my new R3.

David

goodboyr
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by goodboyr

efeballi wrote:^ :')
This should be recited on all alu vs. carbon threads.
I'd like to add that the type of carbon used also plays a role in the fragility/crashworthiness of the frame. For example an RCA has ultra extra hyper super high modulus fibers in it. This is the elastic modulus and determines how much you have to pull each fiber to get a unit amount of deflection. However, these fibers have the same (sometimes even less) ultimate tensile strength with lower-end fibers.
Having a very high elastic modulus allows the engineers to use less material to achieve the same stiffness (remember: amount of force to get deflection) in the frame. This has 2 consequences:
-it reduces the wall thickness. Think of it like a gas pipe versus a soda can, even if they were scaled to have the same compressive or torsional strength, it is much easier to dent a soda can.
-it reduces the ability of the material to tolerate local stresses. As all fibers have a very high modulus, none of them will be willing to bend(by lengthening) to adapt to the shape. And thus, snap. And create local defects, which grow with repeated cycles, and catastrophically fail.
So, lower-end carbon frames are less fragile than higher end ones. Cervelo R3 is hardier than RCA. Emonda S is sturdier than Emonda SLR. Scott Addict 20 is more bombproof than Addict Team Issue.

My two cents...


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Although part of what you state is true, for the rca other materials and reinforcements have been added to make the frame just as sturdy as the lower end frames. So, your conclusion that the higher end frames are less sturdy is not true, in particular for the rca.

efeballi
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by efeballi

You're correct. The RCA was just an example and it was what springed to my mind when I thought about a bike with hi-mod carbon fiber. IIRC they collaborated with 3M to develop a new resin and all that. For RCA you may substitute R5 or any other bike that uses the same molds but different material.

It won't be exactly correct to say that the lower end the frame, the more durable it will be but 90% of the time, it's true. Cervelo had actually stated that the S3 or R3 (can't remember which) was more durable than its big brother.

My examples and reasoning were based on everything except the fibers being the same.




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