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Minor Carbon Repair Advice

swissjswissj Posts: 59
edited September 2010 in Workshop
I have a habit of tinkering with my bikes and my latest has led to my undoing!

My newest steed is a Felt AR4 and I love it to bits, it looks great and rides sweetly so I like to make sure that everything is just so

A few weeks ago I looked up in the manual the torque setting for the seat post, when I noticed that torque settings for the bottle cages were also listed on the page

It suggested 4nm so I ratcheted up my torque wrench and got to work, without thinking that It was an unnecessary adjustment to make!

As I tightened the first bolt on the downtube, I got concerned with the number of turns it took so I stopped....too late though.

The cage I was fitting was a Tacx Tao and it had bit into the carbon around the mounting point and a small crack had appeared.....censored ! I felt sick to my stomach I can tell you!

I took it back to my supplier to be assessed and they said it was only a crack in the laquer (phew) and my question to you is this?

Is there any simple fix that you know of that I can do to stop the small crack(s) from spreading without causing harm to the carbon frame? I fear that if they are left untouched they could creep and I certainly don't want that to happen!

Yours tinkeringly,



  • The frame is no longer safe and should not be ridden (cracks in carbon propagate, potentially leading to catastrophic failure. There are firms that do carbon frame damage assessment and repairs. There are two australian companys that I know of (a google search should find similar repairers in your location):

    I spoke with a rep from carbon cycle repairs at a recent expo and he explained the process. Too long to describe here, but it was convincing.

    I promise, the cost of the frame repair will be a LOT less than the dental bills when the frame fails, and it wont be off the road for too long.

  • Sorry, I missed the bit about the crack only being in the lacquer. Silly, but hopefully the links will be helpful to someone.
  • amaferangaamaferanga Posts: 6,789
    A bit of clear nail varnish should do the trick.
    More problems but still living....
  • btw torque wrenches are usually out, you can get yours calibrated (you get a piece of paper saying how much it's out per setting)
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
  • dmch2dmch2 Posts: 731
    Torque wrenches will be at their worst towards the extremes of their ranges 4Nm is likely to be right at the bottom (unless it's a tiny torque wrench).

    Also sounds like you need a washer or something to keep the cage off the tube?
    2010 Trek 1.5 Road - swissstop green, conti GP4000S
    2004 Marin Muirwoods Hybrid
  • softladsoftlad Posts: 3,513
    using a torque wrench on a bottle cage bolt - seriously...???

    No offence, but did it not occur to you that what you were doing was fkin ridiculous..??
  • Useful comment thanks

    Torque values were in the handbook so I used them. Can't undo whats been done so there is no point in dwelling on it

    In relation to the nail varnish thing, I've heard its ok on metal frames but should be avoided on carbon

    Does anyone out there know if this is true or not?
  • softladsoftlad Posts: 3,513
    swissj wrote:
    Useful comment thanks

    I detect sarcasm, but if it means that you might think before cracking open the torque wrench next time, then it will have been useful.....
  • jairajjairaj Posts: 3,009
    You need to be careful on what you use to fill in the crack. The solvent in nail varnish could dissolve or soften the resin or it could be fine? There are many companies that deal with carbon fibre manufacture give them a call and seek advise on what would be suitable materials to use.
  • i mate carbon can be very dodgie the glue used to stick the carbon strands together can react badly to sertain chemicals i sugest you leave it well alone put a sticker on it like the saying out of sight out of mind
  • That sounds like a good idea!

    I may just do that
  • Use a spell check mate.
    Say... That's a nice bike..
    Trax T700 with Lew Racing Pro VT-1 ;-)
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