carbon seat posts - DOs and DON'Ts

I got a Look ErgoPost carbon seatpost of whatthekoon a while back and am finally getting off my arse to install it. I’ve never used carbon post before so I’m looking for some advice.

this bike forums thread says that the correct tension is 12-15nm but that’s on a frame with an “internal wedge clamp”. Will this be the same on an 853 steel frame with the usual type of clamp?

I can’t find anything to tell me how tight to do the saddle clamp either. there seem to be a couple of reports about the saddle slipping back unless you tighten the fuck out of it. anyone got any suggestions for preventing this?

I was always told to grease the fuck out of alloy seat posts to stop them binding. Is carbon the same?

any other pointers in regards to carbon seat posts would be great.


DON’T grease carbon, make sure the post is clean and dry, seat tube is clean, dry and smooth (ie free of grease and burrs). You might try to get hold of some carbon prep to help stop slipping alternatively some folks use powdered chalk.

Put it on ebay and buy a Thomson.

Torque settings…dunno for that post, you could try calling one of the shops that sells a bit of LOOK (Freedom Machine in Pt Melb maybe?). Whatever the setting is, use a decent torque wrench.

You might also want to run a caliper over it to check the diameter, some ergopost batches a while back allegedly had manufacturing tolerance problems.

…as well as chalk, toothpaste and even hairspray do the job.

I’ve got a Look Carbopost and I’ve had no problems at all. Both in an 853 frame and now a Cannondale.

As the Captain said, make absolutely sure the frame is clean and dry, and the post too.

I dunno about the torque - I just tightened it only enough that it wouldn’t move and it’s been fine. Make sure there are no burrs in the frame that can scratch the post. With the 853 frame (I’m assuming it’s got a brazed on seat clamp) make sure the top of the seat tube is round and the slot isn’t bent inward.

If in doubt, don’t use it. A broken seat post in use can be catastrophic.

not too mention bloody painful!

carbon and steel… :cry:

i know i know but this is purely an experiment in vibration damping for endurance riding.

thanks for the advice. fortunately i have a massive bag of chalk powder.

this is a timely thread since i just spent 2 hours removing a carbon post from a Ti frame today.
it had been fitted with chalk, then ridden in the rain.
then ignored for a while.
2 hours.
all of which could have been avoided if they had contacted a good bike shop and got carbon safe grease and fitted as per normal.

i was worried when we first started to do lots of carbon posts and so i contacted LOOK to get the story from the horses mouth.

official advice given to me by their technical adviser was to use a carbon inert grease and a well calibrated torque wrench. apparently chalk can seize the post and any other product like toothpaste or hairspray has the potential to fuck your gear.

clean the seat tube.
i mean really clean it.
a light ream (i said LIGHT, do NOT remove tube material, only the crap built up on the inside of the tube) and then a good clean with a spirit and clean rag. making a giant Qtip out of a length of dowl and a set of undies is a good thing.
check the collar edge is slightly rounded to prevent a sharp edge (this is basic general seat post stuff you should be doing anyway), then check the pinch is closing to a parallel gap, not over tightening to crack it.
do the pinch bolt up to the recommended torque setting and try it. if it slips, you need to go back to an lloy or steel post and surrender your dream of carbon glory.

that is the word from the LOOK guy.
but he’s only a cheese eating surrender monkey, so take your chances.

Sorry for hijacking your thread, however it is a carbon related topic, not seatpost but fork. What type of paint is safe for carbon fork?

don’t worry about the paint, it’s the primer you want to be sure of.

go to a good auto paint store and ask them about carbon safe primer.
they will probably ask what resin has been used. you’ll need to check with the fork manufacturer for that, or just get a generic inert one.
once the fork is properly primed, you can use any paint you like.

thanks Lupine :slight_smile:

Found some valuable information from Sheldon’s site:


Q: How can I paint over carbon fiber wheels (e.g. Specialized tri spoke, disc wheels and Zipp wheels)? How hard is it to do custom paint on carbon fiber? What materials do I need? Any recommended readings or URLs ???

A: Yes, you can paint over carbon fiber. Call JB for a pro job, or do it yourself. In my experience this is how it’s done:

1.) Remove stickers and their adhesives (I use DX-330 or acetone).

2.) Hand sand off some of the old clear coat or paint, if present. Decals under the clear coat can be sanded smooth this way. Stop sanding immediately at any spot if you touch carbon. It is incredibly easy to remove carbon by hand sanding. Watch especially near sharp edges (airfoil trailing edges on wheels, frames and forks) and parting lines on molded parts (often along the center line of frames and wheels, often along the sides of forks). Wet sanding helps keep the dust down.

3.) Clean the surface mechanically and chemically as follows:

  • Mechanically clean: remove stuff like paint flakes, old bits of dried substances, stickers and their adhesives, decals, flapping plies, scale, crud, etc.

  • Chemically clean: remove grease and oil: fingerprints, real grease from old bike parts, oil from the old bike chain, etc.

  • One last wash: rinse and scrub with acetone until white paper towels come clean.

4.) Prime using Fill’n’Sand or similar. Fill’n’sand is just a high-build primer intended to hide small imperfections, which, depending on your level of perfectionism, is optional ;-). Any similarly described product should do.

5.) Paint using regular paint (Imron, Deltron, PPG, spray can, etc.) as usual. Do not exceed 100 degrees F. Some pinholes may appear. I think this may be outgassing. Bake at lower temps or let the paint dry at room temp to avoid.