3/26/15 12:00 PM

I have an Easton EC90 carbon seatpost in my steel Pinarello Gavia TSX. I used a little bit of yellow grease for insertion. Haven't touched it for some time and it has held fine but I wonder if I should be taking it out, cleaning out the grease and using carbon paste instead? Is it better to just leave alone?

Also, it is a 350mm post and I have 145mm above the collar, and 205mm inside the seat tube. That's 125 more than the minimum insertion. Can I shorten the seatpost, or is 5 inches of carbon not worth the effort? It is actually a pain wrestling 205mm down into the steel seattube.

3/26/15 12:21 PM

Chop that sucker. It doesn't have to extend much beyond the seat stay/top tube junction.

3/26/15 3:05 PM

Agree, chop it. Be sure to leave at least the minimum insertion length below where you set it but otherwise the extra is doing nothing.

I'd remove it and check that every thing is clean and rust free every so often. Using carbon paste instead of grease is probably worthwhile even if grease has caused no problems so far.

3/26/15 7:03 PM

I'll be the voice of dissent. I have some chopped seatposts that are too short for the sloping frames I have had. I think the weight savings is meaningless but having a post long enough matters.

Probably a good idea to pull a seatpost sporadically and regrease or carbon paste it.

3/26/15 7:33 PM

Carbon assembly paste is just grease with some grit in it. No need to use it if the post doesn't slip. I'm from the school that says "everything on the bike should be taken apart, wiped clean, and re-greased on a regular basis." I do this roughly every 10K miles and have never had anything seize. Parts last longer when you have contact surfaces coated with grease.

3/27/15 11:53 PM

I noticed that the Lynskey I recently purchased has an Al insert in the seat tube which appears to have been deliberately ridged when machined in order to reduce slipping of the seatpost:

3/28/15 7:58 PM

...is that if exposed carbon fiber contacts the metal, a galvanic reaction can occur and cause corrosion. If the post is clear coated to prevent carbon-metal contact, the problem is prevented. Greasing can help somewhat, but it will get squeezed out of the areas with the highest clamping force on the post.

4/1/15 5:58 PM

That ribbed for her pleasure seat tube liner will ruin your seat post. In just a few rides the ribs will groove the post. A better idea is to glue in a carbon or fiberglass liner and machine it to size. The glue will prevent the galvanic corrosion issue mentioned above. (an answer to a huge problem on aircraft that mix carbon and metal structures)