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What constitutes “damage” to a carbon seat post

Recently got a carbon seat post for first time (titanium frame).

Was advised to tighten clamp to around 6-7 Nm. Not sure if 7 was too tight or I went some way past this due to torque wrench being faulty (maybe), but there was a scary squeaking.

So I backed off the pressure and took post out to have a look

Didn’t see any cracking or compression , but there are two (seemingly) surface scratches each about 1.5 inches longitudinally up the post where it was tightened against the metal seat tube

Should I be worried? Is the post likely to fail? LBS reckons should be ok, even if “officially” “damaged”

Thanks for thoughts

Posts

  • oxomanoxoman Posts: 9,281
    If you used carbon paste that can sqeak when tightened up.
    Too many bikes according to Mrs O.
  • dowtchadowtcha Posts: 437
    Who advised at 6-7 Nm? Just for reference the numbers on carbon parts are the max and not the recommended. What torque does the manufacture have on the part? I set mine to 4Nm, No idea if it is ok to use but if the sound as the post getting compressed then I would replace and but it down to a lesson learned.
  • Thanks both. Yes I used carbon paste. No torque specified on post or clamp. I’m no going to name supplier, but they even said 9 or 10 Nm wouldn’t do harm. I’ve now set to 5
  • step83step83 Posts: 4,044
    Torque figures quoted are usually ones that are enough to hold the post in place an below the tolerance where it would cause damage, I have a post on mine which has what appears to be a nasty crack, in fact its a long scratch.
    Carbon paste reduces the amount of torque required to keep the post in place so usually 4-5nm is ample. For example the Deda post I have gives 6nm as a max the torque key I used is set to 5nm an holds it perfectly well. 9-10 would usually be an alloy post.
  • fenixfenix Posts: 5,437
    I think you're fine. My carbon posts haven't let me down. I did have 2 alloy lightweight ones that the saddle mount plug came out of though - guess the saddle was too far back on the clamp and it levered out after a bump.
  • timothywtimothyw Posts: 2,482
    As has been discussed elsewhere, these torque measurements are somewhat meaningless as a greased bolt at 5nm will be applying much more force than a dry bolt at 5nm torque.

    It's probably fine but keep an eye on it.
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