# Does carbon paste needs to be reapplied?



## ToiletSiphon (Jul 23, 2014)

Do you need to wipe old carbon paste every now and then and replace it with new? 

Last year, my bike started creaking at the end of the season. I figured out that it came from the seat post. Took it out, cleaned it, reapplied new paste. No more creaking. About a year later I am getting the same sound from the same area. Will probably do the same thing.


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## velodog (Sep 26, 2007)

ToiletSiphon said:


> Do you need to wipe old carbon paste every now and then and replace it with new?
> 
> Last year, my bike started creaking at the end of the season. I figured out that it came from the seat post. Took it out, cleaned it, reapplied new paste. No more creaking. About a year later I am getting the same sound from the same area. Will probably do the same thing.


I don't understand the question.

You did it once and it stopped the creak. If I told you that it wasn't necessary would you just leave it as it is, or would you wipe off the old, and apply the new, in an effort to stop the creak?


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## ibericb (Oct 28, 2014)

Carbon assembly paste is nothing more than grease with a gritty substance added (usually silica) to provide grip. It should only be used between parts that should not move in use. Clean and reapply periodically for he same reason you put it there in the first place. On seatposts, it usually a good idea to take them out annually, clean, and reinstall. If that involves carbon paste, so be it.


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## ToiletSiphon (Jul 23, 2014)

I was going to do it regardless of the answers, I was just curious to know if there could be something inherent to carbon paste that could lead to this.


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## ibericb (Oct 28, 2014)

ToiletSiphon said:


> ... I was just curious to know if there could be something inherent to carbon paste that could lead to this.


Probably not.


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## bvber (Apr 23, 2011)

ibericb said:


> Carbon assembly paste is nothing more than grease with a gritty substance added (usually silica) to provide grip.


I'm going to try a home made version. Small piece of rock or a pinch of sand, hammer, hard flat surface and grease. :idea:


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## ibericb (Oct 28, 2014)

bvber said:


> I'm going to try a home made version. Small piece of rock or a pinch of sand, hammer, hard flat surface and grease. :idea:


Sounds like an idea - maybe you'll create a new grinding compound.


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## robt57 (Jul 23, 2011)

bvber said:


> I'm going to try a home made version.


Valve grinding/lapping compound from NAPA probably save you the time for the experimentation.


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## DaveG (Feb 4, 2004)

ibericb said:


> Carbon assembly paste is nothing more than grease with a gritty substance added (usually silica) to provide grip. It should only be used between parts that should not move in use. Clean and reapply periodically for he same reason you put it there in the first place. On seatposts, it usually a good idea to take them out annually, clean, and reinstall. If that involves carbon paste, so be it.


I don't believe there is any grease in carbon paste. The ones I've used have some sort of inert gel. I know this is hotly debated but many feel grease can damage carbon.


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## ibericb (Oct 28, 2014)

DaveG said:


> ... I know this is hotly debated but many feel grease can damage carbon.


So what do those who believe that recommend for bearing surfaces in headsets and BB's?

Really - it's not controversial, at all.


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## DaveG (Feb 4, 2004)

ibericb said:


> So what do those who believe that recommend for bearing surfaces in headsets and BB's?
> 
> Really - it's not controversial, at all.


I am not aware of any BB or headsets where the bearings ride on a carbon surface.


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## robt57 (Jul 23, 2011)

DaveG said:


> I am not aware of any BB or headsets where the bearings ride on a carbon surface.



I can see using such a compound on the BB30 cups in a carbon shell though... Bearings get nastified the cups could spin in the BB shell maybe?


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## ibericb (Oct 28, 2014)

DaveG said:


> I am not aware of any BB or headsets where the bearings ride on a carbon surface.


Typically the installations include applying grease to the mating carbon parts that make up the seat for the bearings, e.g., grease the inside of the BB shell. Those are pretty general and generic type installations. If you look at a service manual (like this one from Trek), or generally at Zinn's guide, you'll find instructions that call specifically for applying grease to the surfaces on carbon frames that form the mating seat for bearings. Then there was this from Craig Calfee as it appeared in a Technical Q&A with Zinn Lennard Zinn column:

_"Thankfully! An opportunity to dispel the myth that one shouldn’t grease a carbon post!I don’t know where the myth started, but *carbon composites are not affected by grease*. ... *About the only common chemical that will hurt carbon fiber is paint remover* (which attacks the resin between the fibers). But there are many solvents that will dull a nice paint job.
Craig Calfee"_​
It's not an issue, but the folklore persists.


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## DaveG (Feb 4, 2004)

ibericb said:


> Typically the installations include applying grease to the mating carbon parts that make up the seat for the bearings, e.g., grease the inside of the BB shell. Those are pretty general and generic type installations. If you look at a service manual (like this one from Trek), or generally at Zinn's guide, you'll find instructions that call specifically for applying grease to the surfaces on carbon frames that form the mating seat for bearings. Then there was this from Craig Calfee as it appeared in a Technical Q&A with Zinn Lennard Zinn column:
> 
> _"Thankfully! An opportunity to dispel the myth that one shouldn’t grease a carbon post!I don’t know where the myth started, but *carbon composites are not affected by grease*. ... *About the only common chemical that will hurt carbon fiber is paint remover* (which attacks the resin between the fibers). But there are many solvents that will dull a nice paint job.
> Craig Calfee"_​
> It's not an issue, but the folklore persists.


I am not a materials expert so I can't offer any opinion. I read Zinn's article and he said that Calfee offered a "differing opinion on the subject of whether to grease a carbon seatpost". So I take that as other don't agree. So I still say my characterization of "debated" is intact. I used carbon paste on my carbon seatpost because it costs like $2 a packet so why tempt fate. Also, if paste allows for lower torque settings that is a good thing. I slather plenty of grease on my steel bike seatposts though


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## ibericb (Oct 28, 2014)

DaveG said:


> ... So I take that as other don't agree. So I still say my characterization of "debated" is intact.


It's not really a debate. It's a concern of ignorance vs. informed and knowledgeable expertise. That's not a debate.

Of course you are free follow whatever practice you wish.


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## marathon marke (Nov 14, 2011)

I think (at least some kinds of) carbon paste have small plastic beads that provide the grip. This might also be less abrasive (than silica) on the CF surface, in case of any slippage. The beads probably compress over time and don't do the job as well as they did when the paste was first applied. I usually have to reapply mine once a year also, because of small creaks/ticks. I assume this is why.


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## ToiletSiphon (Jul 23, 2014)

If anyone cares... the clicking noise went away after a good cleanup of the seatpost, greasing of seat collar bolts and wedges in the frame (Cannondale Synapse... weird seat collar), greasing of bolts clamping the saddle and new application of carbon paste to the post.


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## ibericb (Oct 28, 2014)

ToiletSiphon said:


> If anyone cares... the clicking noise went away after a good cleanup of the seatpost, greasing of seat collar bolts and wedges in the frame (Cannondale Synapse... weird seat collar), greasing of bolts clamping the saddle and new application of carbon paste to the post.


It sure is cool when a plan works. Enjoy peaceful riding.


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## marathon marke (Nov 14, 2011)

:thumbsup:


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## rawjunk (Jun 25, 2016)

ToiletSiphon said:


> If anyone cares... the clicking noise went away after a good cleanup of the seatpost, greasing of seat collar bolts and wedges in the frame (Cannondale Synapse... weird seat collar), greasing of bolts clamping the saddle and new application of carbon paste to the post.


Is your Synapse still noise free? I have a 2016 Synapse Carbon and did those things but it only reduced the clicking. How tight did you tighten the clamp bolt?


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## ToiletSiphon (Jul 23, 2014)

rawjunk said:


> Is your Synapse still noise free? I have a 2016 Synapse Carbon and did those things but it only reduced the clicking. How tight did you tighten the clamp bolt?


Yes, still noise free. The saddle clamp is at 9.2 nM, seatpost clamp at 5 nM. Don't go over 5nM with that part or you will break your frame.

Envoyé de mon XT1563 en utilisant Tapatalk


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## Lombard (May 8, 2014)

rawjunk said:


> Is your Synapse still noise free? I have a 2016 Synapse Carbon and did those things but it only reduced the clicking. How tight did you tighten the clamp bolt?


I have a 2014 Synapse with this seat post issue. The shop keeps cleaning and re-applying carbon paste. The creaking goes away for a few weeks, but eventually comes back. Done this three times. Hmmmmm.


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## rawjunk (Jun 25, 2016)

Yeah there seems to be few of us. I just cleaned and re-greased mine. Going to test it tomorrow and probably get disappointed again 

Do you have lot of seatpost showing? Carbon or aluminium post? I'm thinking of buying new seatpost.


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## Lombard (May 8, 2014)

rawjunk said:


> Yeah there seems to be few of us. I just cleaned and re-greased mine. Going to test it tomorrow and probably get disappointed again
> 
> Do you have lot of seatpost showing? Carbon or aluminium post? I'm thinking of buying new seatpost.


Aluminum post, carbon frame. Yes, I have a lot of seatpost showing.


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## rawjunk (Jun 25, 2016)

Here is how it sounds now: 






Don't know what to do anymore. Do I send it back or try a different seatpost?

I'm pretty sure it's the seatpost clamp...


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## Lombard (May 8, 2014)

rawjunk said:


> Here is how it sounds now:
> 
> 
> 
> ...


Mine doesn't creak as often as yours. At first I was worried the noise was from the headset and was then relieved it was only the seatpost.

When I first got the bike, the seatpost would actually slide down. Now, it just creaks without moving. I guess that's an improvement eh? :rolleyes5:


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## rawjunk (Jun 25, 2016)

That was a pretty terrible road, even on Finnish standards. Dropped the seat today by 2cm and did 2 hours without clicking :thumbsup: If it stays silent this weekend, I'll order longer seatpost on sunday.

I wonder should I buy carbon or cheap alloy one? BBB makes skycraper bsp-20 in 25,4mm and it's pretty heavy, so I'm thinking it wouldn't be as flexy as Cannondale C2 carbon seatpost.


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