Carbon layup

bcur7
bcur7 Posts: 10
edited March 2012 in Road buying advice
Can someone explain to me what the differant type of carbon structures are. We see terms like Toray 700/800, 3K, 12K.... what do they mean.

Comments

  • styxd
    styxd Posts: 3,234
    3k and 12k are just the aesthetic finishes. Makes no difference to anything (except 12k looks awful!)
  • rake
    rake Posts: 3,204
    in the bike world it does seem to mean what the finish looks like, but i believe it is called the tow of the fiber which means the thickness of it, 12 k means 12000 fibres per mm2 cross section or something like that i cant remember the units. so 12k is 4x thinner than 3k. it means you can pack more fibres with less resin with smaller gaps between, less resin means a bit less weight. the tow number (k) has nothing to do with type of fiber or properties as each type can come in various tow sizes. toray is the name of one of the outfits that make raw fiber, also one of the biggest and highly rated. carbon fibres only really vary in chain length and side branches at molecular level which influences its properties.carbon bonding is the strongest possible i believe with six electrons, four in the outer shell but needing 8 to be most stable it covalently bonds sharing 4 electrons each making a full outer shell which is close to the nucleus so very strongly attached.this applies to all carbon fibre.there is no premium stuff that is vastly better or different.it tells you very little about the quality of the frame that is more down to the designer.oh the actual fibres are all pretty much the same density so there is no wonder stuff that is noticeably lighter, its only lighter if there is less of it in the bike frame or less resin needed to bond it all together . look on torays website there is a graph of fibre types and their properties but again its mostly down to the design and layup so its pretty much a finger in the air job for us cyclists. ironically with such complexity and variances there are no simple rules of thumb which the average buyer can go by so its all just carbon to us. possible a well designed frame thats a bit heavier maybe likely stronger so like most materials more of it=more strength.
  • sd517
    sd517 Posts: 15
    Think this is a good summary:

    http://www.parrotti.com/carbonf.html