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  1. #1
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    Carbon seatpost in Aluminium frame - To grease, or not to grease? Carbon paste etc?

    Hi Everyone,

    Just after a bit of advice as to the installation of a carbon seat post in an aluminium frame... I have seen so many conflicting bits of advice, I am a bit lost.

    To precis:

    - I have a WCS Ritchey carbon post to fit to my Trek Fuel Ex 5 29er
    - I have cleaned out the tube as much as possible after removing the stock seatpost, although some grease remains

    Options:

    1. Install 'as is'
    2. Clean out ALL grease and install dry
    3. Install with a new application of grease
    4. Install with a new application of Carbon Paste

    All have been recommended in various places online and in my LBS, so I really don't know which track to follow!

    Any advice from people who have actually done this kind of installation would be much appreciated!

    Many thanks,

    Marc
    2014 Trek Fuel Ex 5 29er
    2014 Trek Superfly 6
    2014 Trek X-Caliber 5 (for sale)
    2014 Scott Aspect 740 (650b)

  2. #2
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    I used paste:
    Carbon frame aluminum post
    carbon bars aluminum stem.

  3. #3
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    I have tried all 4 of those options and never had a problem with any of them. Right now I'm using some white grease on my post, mostly because it is a tight fit and I don't want it scratching.

  4. #4
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    Carbon seatpost in Aluminium frame - To grease, or not to grease? Carbon paste etc?

    Silicone spray. I think Syntace advices that for aforementioned use. I do this and it works ok. Carbon paste is more "scratching".
    12 Anthem X29
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  5. #5
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    Carbon post in aluminum frame here. Just cleaned the old grease out of the seat tube as best I could and installed. Hasn't moved in over a year. Carbon paste is only if moving is an issue; it adds some abrasion. I did use that on my carbon handlebar with my Syntace stem as it was recommended but the bar had a rough section on it and I probably didn't need it. I don't think you will screw anything up. Carbon certainly won't seize up in the metal frame so I vote for dry (like I did) and only use paste if slipping is an issue. Follow the recommended torque on the seatpost bolt!!!
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  6. #6
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    I use grease for steel frame / alu post, so it won't seize.
    I use grease for steel frame / carbon post, so the frame won't rust. (Make sure the grease is chemically suitable for plastics!)

    For an aluminum or titanium frame and carbon post, neither of the above applies: go bare or add paste if it slips.

  7. #7
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    Some people will recommend friction paste with the logic that it allows you to tighten your seatpost clamp less, and therefore reduce the risk of overtightening/crushing. But I'm with TiGeo, I haven't had slipping problems running bare or with grease.

  8. #8
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    dbl post

  9. #9
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    You are so wrong, carbon aluminum do seize, You should check it... Maybe I am wrong but I have heard plenty of people with stuck posts in carbon frames. There have also been posts about Enve rims and aluminum nipples.

  10. #10
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    Quote Originally Posted by MTBMILES View Post
    You are so wrong, carbon aluminum do seize, You should check it... Maybe I am wrong but I have heard plenty of people with stuck posts in carbon frames. There have also been posts about Enve rims and aluminum nipples.
    yes I have heard that too, mainly with alloy nipples and carbon rims, but I haven't seen it yet. I made some fibreglass paste from silicon grease and glass dust (epoxy thickener) which seems to have worked but it's a bit of an experiment. Just made a putty like mixture and smeared it on. I figure it's just about having some fine grit in a friendly medium.

  11. #11
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    Thanks for the advice everyone, I very much appreciate the input!

    Going to finish cleaning the seat post tube tonight to get the rest of the old grease (and mud) out, and install the new post 'dry' for now. I'll move it every week or so initially just to check that it is not seizing, and then see how it goes. If it does slip, I'll look again at the carbon paste option.

    Thanks again!
    2014 Trek Fuel Ex 5 29er
    2014 Trek Superfly 6
    2014 Trek X-Caliber 5 (for sale)
    2014 Scott Aspect 740 (650b)

  12. #12
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    I did some looking..yes..some folks reporting frozen carbon posts in Al frames...yikes! May need to take mine out this weekend to move it..its been over a year!
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  13. #13
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    why gamble?...

    after a $100+ investment in a carbon post, why not just do it right? The seat post picture shows the original aluminum post that slipped...new SLK carbon installed with Finish Line and hasn't moved in 100+ miles...it's a perfect world
    Attached Thumbnails Attached Thumbnails Carbon seatpost in Aluminium frame - To grease, or not to grease? Carbon paste etc?-616shv%252bikel._sl1500_.jpg  

    Carbon seatpost in Aluminium frame - To grease, or not to grease? Carbon paste etc?-dsc01482.jpg  

    Last edited by time229er; 01-08-2014 at 07:14 AM.
    2014 Nail Trail 29er

  14. #14
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    From Niner's manual for my RDO post:

    The seat tube MUST be free of all lubricants, use rubbing
    alcohol to carefully clean the inside of the tube and remove all traces of
    grease, dust or other compounds.
    Apply a thin film of Carbon Assembly Compound (Tacx, FSA or other) to
    the post and inside the seat tube to ease installation, adjustment and
    removal.

    Guess I know what I am doing this weekend!!
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  15. #15
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    Ah great info - the search for Carbon Assembly Compound begins!
    2014 Trek Fuel Ex 5 29er
    2014 Trek Superfly 6
    2014 Trek X-Caliber 5 (for sale)
    2014 Scott Aspect 740 (650b)

  16. #16
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    Carbon seatpost in Aluminium frame - To grease, or not to grease? Carbon past...

    Quote Originally Posted by Marc2211 View Post
    Ah great info - the search for Carbon Assembly Compound begins!
    I used a little smudge of Colgate toothpaste as "carbon assembly compound" to fix a slipping carbon post in Al frame. Worked like a champ and left my bike minty fresh.

    I believe I picked up the tip on a (gasp!) road bike forum.

  17. #17
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    I have some Finish Line and some some stuff I got from Syntax with my stem for carbon bars..will use that.

    Sent from my SCH-I545 using Tapatalk
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  18. #18
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    I've found that carbon paste makes my post more prone to creaking. I run mine bare.

  19. #19
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    I have a Easton Haven post in I my Epic Comp. I noticed after 6 months of not moving it; it has become very difficult to remove.

    After getting it out the post looks like its starting to breakdown. It hasn't been moving inside the seat tube but looks like it has been.

    Sent from my DROID RAZR using Tapatalk

  20. #20
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    Quote Originally Posted by AOK View Post
    I used a little smudge of Colgate toothpaste as "carbon assembly compound" to fix a slipping carbon post in Al frame. Worked like a champ and left my bike minty fresh.

    I believe I picked up the tip on a (gasp!) road bike forum.
    I like that. Of course if you ride in wet conditions its not going to last long.

  21. #21
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    Leonard Zinn and Craig Calfee, both custom bike builders, discuss how grease on carbon posts is ok, even a good thing:

    Calfee:

    I donít know where the myth started, but carbon composites are not affected by grease. Our advice is simple: If the seatpost fits tight,grease it. If it slips, de-grease it. As has been known formany years, when aluminum and carbon fiber contact each other, galvanic corrosion can start.

    Technical Q&A with Lennard Zinn - More greased carbon - VeloNews.com

  22. #22
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    Got some carbon assembly paste form my LBS this afternoon - initial installation complete!

    Damn scared tightening it up as my torque wrench is at work, was really fearful of cracking it. I'll be riding in standing up for my whole commute tomorrow morning until I can tighten it properly!

    Carbon seatpost in Aluminium frame - To grease, or not to grease? Carbon paste etc?-photo-1.jpgCarbon seatpost in Aluminium frame - To grease, or not to grease? Carbon paste etc?-photo-2.jpg
    2014 Trek Fuel Ex 5 29er
    2014 Trek Superfly 6
    2014 Trek X-Caliber 5 (for sale)
    2014 Scott Aspect 740 (650b)

  23. #23
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    Quote Originally Posted by Marc2211 View Post
    Damn scared tightening it up as my torque wrench is at work, was really fearful of cracking it. I'll be riding in standing up for my whole commute tomorrow morning until I can tighten it properly!

    Jeez man its not made of egg shell! I've been tightening my seatpost clamp with no torque wrench for years.

    Yeah so I cracked one :/

    But that was when I thought those things were indestructible. I was on a muddy ride and adjusting my seat height. The post was dirty so it was a really tight fit. I tried closing the quick release and it was was really tight but I forced it closed. As I mentioned before, I didn't even know it cracked until I got home, and it still held my weight.

    I think you can use common sense to tighten it enough to keep it from slipping so you don't have to stand up on your whole commute tomorrow!

  24. #24
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    Quote Originally Posted by smilinsteve View Post
    Jeez man its not made of egg shell! I've been tightening my seatpost clamp with no torque wrench for years.

    Yeah so I cracked one :/

    But that was when I thought those things were indestructible. I was on a muddy ride and adjusting my seat height. The post was dirty so it was a really tight fit. I tried closing the quick release and it was was really tight but I forced it closed. As I mentioned before, I didn't even know it cracked until I got home, and it still held my weight.

    I think you can use common sense to tighten it enough to keep it from slipping so you don't have to stand up on your whole commute tomorrow!
    and if your **** don't fly ???
    2014 Nail Trail 29er

  25. #25
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    Pulled mine out tonight. No issues at all..its been a year and I installed it dry and cleaned the seat tube with rubbing alcohol etc. to fully degrease it prior to installation. I used some Syntace carbon paste I had left over from my stem and re-installed it.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

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