Kris Flatlander

Do I need to grease it? I know that you don't grease a carbon post in an aluminum frame right? But how about an aluminum post (Profile Design Fast Forward) in a carbon frame (Trek Madone 5.2 SL) I'm asking because I plan to just swap out my seatposts with different seats for tri training. Thanks for any help.

blandin

Two articles by Leonard Zinn on the subject. You need to read both to have the complete picture.

https://www.velonews.com/tech/report/...es/8835.0.html
https://www.velonews.com/tech/report/...es/9023.0.html

blacksquid

What about graphite? I used a bit of it to get a Campy carbon seatpost into a Tete. It was a tight fit and the graphite was handy.

linux_author

- i thought most CF frames have an aluminum sleeve insert for seatpost support? doesn't Trek do this as well?

aprilia4life

Far out... from those articles it looks like a big fat no...

GuitarWizard

I don't grease my Thomson post in my 5200....not supposed to grease alu seatposts in carbon frames.

blandin

GW, check this out.

Response from Craig Calfee in the 2nd VeloNews article I posted above.

Dear Lennard,

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. Our advice is simple: If the seatpost fits tight, grease it. If it slips, de-grease it. As has been known for many years, when aluminum and carbon fiber contact each other, galvanic corrosion can start. That is why Calfee uses a fiberglass sleeve as a seat tube shim. Aluminum seat tube (or sleeve) and a carbon post will result in corrosion of the frame and possible seizure of the post within the frame. A carbon sleeve on an aluminum post will result in corrosion of the post. Salty environments accelerate this corrosion. Anodizing merely slows it down. 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

aballas

so according to blandin we should avoid the alu-carbon combination altogether?

I'm fine w/ carbon-carbon.....anyone else with me??

itri-45

I had the same question today when I tried to install an aluminum Thomson Masterpiece post on my Orbea Onix carbon frame. I decided to call Thomson because its instruction does not mention anything about grease. According to Thomson’s tech, grease is not required. He also warned that grease on carbon may cause the post more likely to slip and one would tend to over tighten to compensate.

When I went to install my new post, I found out that there’s an aluminum sleeve inside the carbon seat tube so actually it would be aluminum-to-aluminum contact. Thus I’m going to apply some grease to prevent any corrosion or creaking issues.

blandin

No, it's according to Calfee, I'm just the messenger. DrPete has posted about a product that escapes me right now, but it is specifically designed for use with carbon. Maybe he'll chime in.

cc3chan

I have a similar question. Should I use an aluminum shim to fit my CF post to a CF seat tube, or is a CF shim the only safe way to go? I'm thinking of getting a standard 27.2mm post for my R3, which uses the very strange 32.4mm post. There's not too many choices in that size.

DieselDan

Y'all are blowing this way out to left field. The OP is switching posts regularly. No need to grease a post that is being removed at regular intervals.

Kris Flatlander

Thanks for noticing. Ya it will be removed somewhat regularly. At least once every 2 weeks. Probably more like once-twice a week. What would the max time interval be?

Corsaire

No problem, just DO NOT GREASE IT.

Corsaire

texascyclist

Check out this stuff made specifically for Carbon:

https://www.competitivecyclist.com/za...MODE=&TFC=TRUE

The description lists some good reasons for using it.

Skinny Fred

IIRC, this is the type of product mentioned by DrPete.

More recent (Jan 2007) column by Lennard Zinn, who has mentioned carbon assembly paste a few times:
https://www.velonews.com/tech/report/...s/11432.0.html

JayC

I wonder if this applies if the seat post is anodized like the Thomson posts. FWIW, I didnt grease my Thomson post in the Motobecane frame.. in fact, I Loc-Tite'd it so it wouldnt slip

itri-45

Competitive Cyclist's Tacx carbon paste is well recommended for carbon/carbon interfaces but it's unclear what's best for aluminum/carbon contacts, which was the OP's question.

Thomson's advice was that grease is not required. But in my case where I've an aluminum sleeve inside the carbon seat tube, making it aluminum to aluminum, I choose to use grease.

DieselDan

Short answer, you're good. There is nothing in stone, but once a week change out sounds good.

oilman_15106

This stuff works. End of stroy.

Everest

The graphite is actually a good suggestion to use to get a tight fitting post in since all graphite is is carbon.