# carbon assembly paste



## tjjm36m3 (Mar 4, 2008)

I just pull out the carbon fiber seatpost from the carbon frame and the surface of the seatpost that goes in the frame looks pretty scratched up. I have no problem pulling out the seatpost, it wasn't jammed in there. But do I really need to put on some carbon assembly paste? Will the paste decrease friction and the seatpost slide down thru time? If the paste is recommend, can anyone recommend a brand? Thanks.


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## Jeepster82 (Mar 11, 2009)

The paste is to stop the seat tube or whatever from moving. Carbon fiber is very smooth and you will have to torque the bolts down so tight to keep the post from dropping you are gonna crack it. 

The paste increases the friction, and the way I see it carbon paste is carbon paste. If you buy one tube it will be all you need for life, it goes a long way.


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## Kerry Irons (Feb 25, 2002)

*Grease?*



tjjm36m3 said:


> I just pull out the carbon fiber seatpost from the carbon frame and the surface of the seatpost that goes in the frame looks pretty scratched up. I have no problem pulling out the seatpost, it wasn't jammed in there. But do I really need to put on some carbon assembly paste? Will the paste decrease friction and the seatpost slide down thru time? If the paste is recommend, can anyone recommend a brand? Thanks.


You can just use grease if your seat post doesn't slip. If the post slips, then use the assembly paste, which is just grease with some particles in it.


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## Zipp0 (Aug 19, 2008)

Kerry Irons said:


> You can just use grease if your seat post doesn't slip. If the post slips, then use the assembly paste, which is just grease with some particles in it.


There are indeed particles in it, but I am not sure that it is in fact grease. At least it's not standard petroleum based grease anyway.

Bottom line - use it if your post slips. It does work very well and also will prevent your post from becoming permanently stuck if your frame is aluminum or has an alu insert in the seat tube.


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## frdfandc (Nov 27, 2007)

I've been using the following method for the past few years. Just recently I was able to run this past another mechanic with 20+ years of wrenching experience - which included a few years wrenching for a couple of pro-level teams. So far it has worked great. 

If a carbon or alloy post is tight or snug, or if the bike is equipped with an alloy insert use grease.

If using a carbon post, but does not move when the clamp is properly torqued - nothing applied.

If seat post slips - use the carbon grease.


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## wim (Feb 28, 2005)

Zipp0 said:


> There are indeed particles in it, but I am not sure that it is in fact grease. At least it's not standard petroleum based grease anyway. Bottom line - use it if your post slips. It does work very well


It works very well because it's grit suspended in petroleum grease. As far as I know, there's no assembly paste using vegetable grease (bananas, soybeans, olives, etc.) as a carrier for the grit.


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## tjjm36m3 (Mar 4, 2008)

Thanks, I guess I'm ok with what I have before-- nothing. I'll just put some grease on next time. The carbon paste is kind of expensive at $20+ per tube.


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## RC28 (May 9, 2002)

tjjm36m3 said:


> The carbon paste is kind of expensive at $20+ per tube.


There are a LOT of things that are incredibly more expensive than this in a benefit/$ ratio. Besides, $20 is for a tub of the stuff. Which, unless you own a shop or a LOT of bikes, you'll probably never go through.

The Finish Line paste costs about $7 for a 50g tube and is way more than enough for most cases. It will end up costing you much less than $1 to protect that carbon seatpost that you paid dearly for. I think that's a pretty good deal.Don't you?


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## mpk1996 (May 11, 2007)

i would not use regular grease. i have heard of grease getting soaked up in the carbon and destroying it. thats what some of the reps told us anyway. i know some are going to come on here and say they have used grease on their carbon parts since jesus was a baby, but just passing on the info that i got. i use the carbon assem paste and nothing else on all of my carbon parts. anti-seize on all of the metal to metal parts, and grease on bearings and cables (and nothing else).


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## reptilezs (Aug 21, 2007)

mpk1996 said:


> i would not use regular grease. i have heard of grease getting soaked up in the carbon and destroying it. thats what some of the reps told us anyway. i know some are going to come on here and say they have used grease on their carbon parts since jesus was a baby, but just passing on the info that i got. i use the carbon assem paste and nothing else on all of my carbon parts. anti-seize on all of the metal to metal parts, and grease on bearings and cables (and nothing else).


no grease wont get soaked into the carbon unless the carbon and epoxy did not wet out completely during the lay up. if thats the case i wouldnt use any of that carbon.


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## MerlinAma (Oct 11, 2005)

RC28 said:


> ........... Besides, $20 is for a tub of the stuff. Which, unless you own a shop or a LOT of bikes, you'll probably never go through......


Even if you give a dab to your friends with new carbon bikes, you'll never go through that much.

Then they "owe" you.


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## twiggy (Mar 23, 2004)

No grease... mpk1996 is correct.... sometimes the installation movement of parts can cause scratches in the resin/coat over top of the carbon...grease can soak in and expand the fibers....potentially making your parts stick together AND weakening the carbon. I've been told my the Cannondale, Cervelo, and Specialized reps specifically NOT to use grease.


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## ukbloke (Sep 1, 2007)

It is also available in small quantities. I bought some just in case my Tarmac post started slipping. It hasn't yet, so I haven't used any.


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## Kerry Irons (Feb 25, 2002)

*No grease?*



twiggy said:


> No grease... mpk1996 is correct.... sometimes the installation movement of parts can cause scratches in the resin/coat over top of the carbon...grease can soak in and expand the fibers....potentially making your parts stick together AND weakening the carbon. I've been told my the Cannondale, Cervelo, and Specialized reps specifically NOT to use grease.


That's interesting, since all kinds of derailleur and brake parts are made of CF composites, and they are constantly exposed to petroleum oils and greases. CF frames get scratched, and grease/oil is everywhere on bike frames. I've been greasing a CF seatpost for 6+ years with zero issues. I believe that those reps told you not to use grease, but it's worth considering that they might more likely just be covering their a$$ than actually offering fact-based advice.


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## SilverStar (Jan 21, 2008)

The "don't use grease on carbon" thing is a persistent Internet myth. Even Craig Calfee calls BS on this myth, and I'm pretty darn sure he knows what he is talking about:

http://velonews.competitor.com/2005...qa-with-lennard-zinn-more-greased-carbon_9023


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## wim (Feb 28, 2005)

SilverStar said:


> The "don't use grease on carbon" thing is a persistent Internet myth. ]


It's so persistent that the sellers of grease containing friction-inducing particles use the term "paste" or "compound" to sell their products to those who believe the myth that grease is bad for carbon. The clever mantra "don't use grease, use assembly paste" succesfully tricks a lot of people into believing that "assembly paste" is not grease, which, of course, it is.


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## Zipp0 (Aug 19, 2008)

I wonder why then, that my new Easton CF seatpost specifies in the installation instructions specifically to not use grease, and in fact to remove all traces of grease from the seat tube?

I do like the fact that the carbon paste lets you use a bit less torque without slippage while also preveling galvanization.


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## wim (Feb 28, 2005)

Zipp0 said:


> I wonder why then, that my new Easton CF seatpost specifies in the installation instructions specifically to not use grease, and in fact to remove all traces of grease from the seat tube?
> 
> I do like the fact that the carbon paste lets you use a bit less torque without slippage while also preveling galvanization.


There's a good reason for this: if certain manufacturing tolerances come together (smallest possible seat post outside diameter and largest possible seat tube inside diameter), there's a good chance that grease will make the seat post slip. If that happens, people generally cranked the seat post clamping bolt to excessive and, sometimes, damaging torques. With assembly paste, slippage is stopped without having to resort to brute force—exactly as you said.

Don't get me wrong: so-called assembly paste is great stuff. It's just that the thing about about "grease attacking carbon" is pure BS. If grease would attack carbon, the grease in the assembly pastes or -compounds would attack it just as much as plain grease would. It doesn't, and all is good.


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