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Cracking

SupergooseSupergoose Posts: 1,089
edited February 2010 in Workshop
Right, I have broken my 3rd carbon seat post on the trot. Not happy. I have a good 'feel' for steel and alloy but carbon is a new ballgame for me.

Anyway, I cant afford to go on like this. I have succumbed and bought a torque wrench. Can anyone tell me the ball park ratings for the control point bolts? Stem to bars, front mech band, and of course seat pin.

Cheers
Rock 'n' Roule

Posts

  • rakerake Posts: 3,204
    5nm on ritchey stuff. stay away from my bike.
  • deswellerdesweller Posts: 5,175
    rake wrote:
    stay away from my bike.

    :lol::lol:
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  • SupergooseSupergoose Posts: 1,089
    :D 5 nm is alot
    Rock 'n' Roule
  • Smokin JoeSmokin Joe Posts: 2,706
    Supergoose wrote:
    Right, I have broken my 3rd carbon seat post on the trot. Not happy. I have a good 'feel' for steel and alloy but carbon is a new ballgame for me.

    Anyway, I cant afford to go on like this. I have succumbed and bought a torque wrench. Can anyone tell me the ball park ratings for the control point bolts? Stem to bars, front mech band, and of course seat pin.

    Cheers
    Check the edge of the seat tube for burrs, they can cut into the post and cause it to fail. You are unlikely to have overtightened it if you just used an allen key, as previously stated 5nm is bloody tight.
  • rakerake Posts: 3,204
    Supergoose wrote:
    :D 5 nm is alot
    i dont understand why you think thats tight. look at a ritchey torque key you tighten them with two fingers. you could easily get much more than 5nm with an allen key. now if your getting 5kgm which is marked on torque wrenches mixed up on your torque wrench that is thght. its ten times more, 5nm is 0.5 kgm.
  • deswellerdesweller Posts: 5,175
    First of all, it's 5Nm, not 5nm. 5nm is 5 nanometres, which is very very short!

    Secondly, 5Nm is not very much. Easily doable on a screwdriver, no major leverage required.
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  • SupergooseSupergoose Posts: 1,089
    Smokin Joe wrote:
    Check the edge of the seat tube for burrs, they can cut into the post and cause it to fail. You are unlikely to have overtightened it if you just used an allen key, as previously stated 5nm is bloody tight.

    Fair play,I will examine for jaggy bits. Many thanks. 8)
    Rock 'n' Roule
  • SupergooseSupergoose Posts: 1,089
    I notice there hasnt been much feedback regarding torque ratings with the exception of the Ritchey kit. Do folk just guess? As tightening till your elbow clicks doesnt work with this plastic stuff!
    Rock 'n' Roule
  • HonestAlHonestAl Posts: 406
    For what help it might be, the manual for my TCR Advanced - ie carbon frame and tube gives limits of 7.8 to 11.7 Nm. I've always used a torque wrench and set it around 9 Nm and have never had any problem (either with it slipping or cracking)
    "The only absolute statement is that everything is relative" - anon
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