Types of Carbon Weave??

Tombird1
Tombird1 Posts: 63
edited December 2008 in Workshop
I have noticed different carbon fibre fames have different types of weave patterns. Some have very thin flat large fibres in a 'criss-crossing' pattern, while others are quite tightly woven from much smaller fibres in a more linear arrangement like fabric.

I wonder whether there is any strength advantage between them such as having a higher modulus. I've just had a quick search on the internet but couldn't find much.

Bit of a nerdy post but I find it quite interesting :D Can anyone explain this and enlighten my understanding of carbon fibre :wink:

Comments

  • redddraggon
    redddraggon Posts: 10,862
    "Pattern carbon fibre" is normally just something to "look good" and doesn't necessarily have any structural properties.

    Not all frames bother with the woven layer - it adds weight, but won't necessarily make it any stiffer.
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  • gkerr4
    gkerr4 Posts: 3,408
    as above - it i usually just a decorative layer - doesn't really affect the strenght of the frame i don't think.

    My S-Works roubiax doesn't have a top layer and I have to admit it looks a bit weird - like a big lump of plastic, which I guess is what it is. The next model down (expert?) does actually look better as far as frames go but mine is (apparently) lighter and stiffer.

    05042008071.jpg
  • Oh, so you can get carbon fibre without the pattern weave? I didn't know that. And the top layer is purely cosmetic?
  • Thanks for the picture, that explains it.

    It does seem odd though, that frame designers would add anything to a high performance material that would compromise its performance, even slightly, just because the weave layer looks good!
  • redddraggon
    redddraggon Posts: 10,862
    Tombird1 wrote:
    It does seem odd though, that frame designers would add anything to a high performance material that would compromise its performance, even slightly, just because the weave layer looks good!

    The decorative layer can provide protection to the structural carbon though.
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  • gkerr4
    gkerr4 Posts: 3,408
    i doubt it compromises the performance in any way really - it won't detract from the strength and stiffness and it only adds a few grammes - but the decorative weave probably adds a lot of sales value to the frame as it is what people 'expect' to see in a frame. mine is pretty ugly to be honest - it's a good job it is bloody comfortable and light to make up for it!!
  • Actually I'm fairly sure that the Olympic track bikes use visible carbon weave so it can't just be cosmetic? :?
  • gkerr4
    gkerr4 Posts: 3,408
    actually - I say it's ugly but it does match the carbon campag equipment I put on it which is also a sort of 'random' carbon bits pattern - you can kind of see the bottle cage on that picture but the crankset is a bigger more noticable part when you see it in the flesh!
  • Oh protective layer - that makes sense, but doesn't explain track bikes.
  • Yes and like you say there's that 'carbon bits pattern' - I wonder what the advantage of that is? It always reminds me of the pattern you get on some bowling balls!
  • wilwil
    wilwil Posts: 374
    Cervelos don't have a weave pattern and you can see all the bits and pieces under the lacquer in places. Does the weave layer have anything to do with the molding process?

    The Campag carbon cranks are made in in a different way I think.
  • guys, little introduction to carbon on my blog

    http://www.sabbathbicycles.com/ssblog.php under June "Carbon or Ti".

    your may well be looking at very differnt materials; 1) small (maybe even nano) fibres, injection moulded (or via other processes to form a homogeneous material. 2) layered woven material layers injected with matrix - hetrogenious. 3) combination of the above (less likely) or 4) same as 2 but painted so you cant see the weave.

    Dr Iain Roche.
  • Ah Ha, Thank you Doctor.