grease a carbon seatpost?

[CAMPYBOB]

i have a Ti frame and a campy carbon fibre seatpost.

the campy literature says clean grease and oil from inside the seat tube prior to insertion of the seatpost.

yet...

a friend had a campy carbon seatpost seize up in his Ti litespeed after only 3 months. it took major effort and time to remove the seatpost from the frame.

he currently has his coated with an anti-seize compound currently.

any advice? thanks.

 

[tetsuryuu]

I wouldn't touch it if I was you. If you put anything between that post and the clamp, then you increase the pressure necessary to hold the post in place. Most carbon seatposts aren't designed to take that much pressure, so you end up either crushing the seatpost (bad) or an insecure seatpost (also bad). Just my 2c.

As to why your friend's post got bound up, I'm not sure why that would happen. Usually seatposts bind because of a chemical reaction between the different metals used in the frame and seatpost (steel frame, alu post; or even different alloys of aluminum used in both). Carbon is essentially nonreactive, so something else must have happened...

 

[IEatRice4Dinner]

i would say grease it... most say to not do it, but you got to look at all the stuck posts lately. greasing cant hurt, if it slips clean a little off till it dont. all the customers bikes i touch i put a little grease in and tell them why. it's easier then trying to remove a stuck post.

 

[artmichalek]

[size=-1]"If the seatpost fits tight, grease it. If it slips, de-grease it." - Craig Calfee

http://www.velonews.com/tech/report/articles/9023.0.html



[/size]

 

[gclark8]

Chose a graphite based "grease", not a petroleum one. Tighten carbon posts and frames only with a torque wrench to the specs given by the manufacturer!!

 

[fish156]

Carbon is essentially nonreactive, so something else must have happened...

Wrong, wrong, wrong. Please take the time to read the link posted by artmichalek. Carbon and aluminum in contact will have a galvanic reaction.
The resultant stuck seatposts have had to be destructively removed on many occasions. Use common sense to grease, or not to grease.

That grease harms CF is a myth. I know of plenty of stuck CF seatposts and of none that have been harmed by grease. Don't leave your CF posts inserted for years at a time without checking them. I know of one person with a Look CF frame(the funny one with the triangular tubes) that has an AL seatpost that is pretty much a permenant part of his bike now. That is, of course, unless he wants to destroy the frame to get out the seat post.

 

[artmichalek]

Wrong, wrong, wrong. Please take the time to read the link posted by artmichalek. Carbon and aluminum in contact will have a galvanic reaction.

The one thing that wasn't mentioned in that article is that a galvanic reaction requires two things; materials with different galvanic constants, and electrical conduction between the two. Straight out of the box, a carbon seat post has a clear coat on it. Put that surface into contact with aluminum and some water and nothing is going to happen. There are a few things to keep in mind when installing a carbon seat post. Don't trim it to length unless you are going to coat the cut surface with something. Inspect the inside of the seat tube for any burrs or sharp edges and use extreme care not to scratch the clear coat when putting the post in. The use of grease should have nothing to do with corrosion. Putting an aluminum post into a carbon frame is a different story, since there's no clear coat on the inside of the frame.

 

[CAMPYBOB]

thanks for the replies and link.

the chorus seatpost is clear-coated from the factory. with 'what'...i don't know.

i polished the factory-reamed titanium seat tube with very fine (220 grit) crocus cloth and radiused the inside edge of the tube.

the fit between the tube and post is very good...probably only .003" to .005" clearance between the two.

i've been riding/racing since 1972 and am familiar with the aluminum post/steel tube electrolysis problem, but until my friend seized his Ti/carbon rig up i hadn't a clue this combination could pose a problem.