Just bought a Carbon Seatpost - Installation questions and should I be worried?- Mtbr.com
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  1. #1
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    Just bought a Carbon Seatpost - Installation questions and should I be worried?

    I recently upgraded the seatpost on my Marin Rift Zone to a Thomson Elite. However, the setup was not ideal as I had to buy a longer bolt to get the seatpost level due to angle of the seat-tube. Also, the zero setback of the Elite was not ideal.

    So I stumbled across a great deal on an Answer SL carbon 20mm setback post. I'd previously sworn off carbon posts after reading a few horror stories about them, but I decided to purchase it anyway.

    So my first question is how many of you have been riding a carbon seatpost (name brand and with correct torque setting) for a decent amount of time without breaking one?

    Onto the installation: I've read several recommendations to always use carbon fiber paste, but also read recommendations to install dry. For the record, I'm installing the carbon post into an aluminum frame. The saddle rail guides are also carbon. What's the consensus on the use of carbon paste and would I also need to use for the saddle attachment?

    Lastly, the Answer post came with a lock on collar - I'm assuming this is to stop any slippage, but is it really needed?

  2. #2
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    I would not use paste UNLESS the post slipped after being torqued------I had one seize in a frame and it took the mfg to get it back out-was carbon to carbon-I also these days loosen the post every few months just to make sure----I simply want to avoid the situation again----I also ride on the road where many use carbon posts and while not a typical topic have not heard of anyone using paste.

  3. #3
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    Thanks pctloper - how long have you been riding with a carbon post on your mountain bike?

  4. #4
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    AFAIK the carbon paste is also anti-seize, so I don't see why not use, as long as you use good quality. I use a blister from Giant, that I got for free from my LBS. since I use so little every time I assemble anything, a single blister can be used for many assemblies.

    Having that said, I have a carbon seatpost on my road bike only, and the slippage ruined the finishing of the seatpost. Whish I had used carbon paste from the beginning.

  5. #5
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    I've been using an easton EC90 20mm setback road bike post on my hardtail for 4 years and 3 drivetrains now, no issues.

    torque yes (a) seat anchor wedge (giant XTC frame) torqued to Giant specs (10.2nm) and (b) seat rail anchors torqued to Easton specs (5nm)

    no problems, and post does have a wee bit of flex if you twist on it to check if it flexes. I lathered it in TACX carbon paste for install. I applied a strip of 'watch tape' across the post/seat tube interface to see if the post sinks at any time, it never budges, ever.


    same deal as the answer post, -all carbon- except the bolts and nuts
    "Put your seatbelt back on or get out and sit in the middle of that circle of death." - Johnny Scoot

  6. #6
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    Quote Originally Posted by 127.0.0.1 View Post
    I've been using an easton EC90 20mm setback road bike post on my hardtail for 4 years and 3 drivetrains now, no issues.

    torque yes (a) seat anchor wedge (giant XTC frame) torqued to Giant specs (10.2nm) and (b) seat rail anchors torqued to Easton specs (5nm)

    no problems, and post does have a wee bit of flex if you twist on it to check if it flexes. I lathered it in TACX carbon paste for install. I applied a strip of 'watch tape' across the post/seat tube interface to see if the post sinks at any time, it never budges, ever.


    same deal as the answer post, -all carbon- except the bolts and nuts
    Did you use carbon paste on the saddle interface parts too?

  7. #7
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    Always paste a CF post and grease a metal post. No paste on rails, though I do grease them, CF or metal.

    Yes. If it's carbon, worry. Besides strength, lightweight and tuneable flexibility, worry is one of the major consequential attributes of carbon.
    Do the math.

  8. #8
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    Quote Originally Posted by mcbiko View Post
    Did you use carbon paste on the saddle interface parts too?
    no, the rails are alcohol cleaned and metal rail to carbon, no paste. no creaks.

    full disclosure it's this saddle on that post, manganese rails


    Selle Italia C2 Gel Flow Saddle

    Just bought a Carbon Seatpost - Installation questions and should I be worried?-selleitalia.jpg
    "Put your seatbelt back on or get out and sit in the middle of that circle of death." - Johnny Scoot

  9. #9
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    Alright, just finished installing. Cleaned the rails with isopropyl alcohol and installed saddle with no paste or grease - torqued to 4NM (max spec is 5NM). Cleaned inside seat-tube with alcohol, applied Fiber Grip paste to section of seatpost inside seat-tube, and torqued to the same 4NM. Hopefully this is enough to hold - I've put a piece of tape on the post so I can keep track of any slippage.

    I left off the extra collar that came with the post shown in this link https://www.amazon.com/Answer-Produc.../dp/B017P3L0J4

    Or should I still install the collar - I'm guessing its designed as an extra anti-slip mechanism?

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