Stallionforce

Just picked up a used Colnago Master Light, just immaculate, beautiful bike. I knew I needed to have the seat raised, but thought, 'no problem, I can do this at home.' Nope. Post is jammed in the seat tube. Suggestions? Penetrating lubricants? Hulk Hogan biceps?

kycycler

You could try penetrating oil. This will ruin the seat post. My guess is that someone lubed the seat post with grease. This is a no no on carbon.

JiveTurkey

I've been under the impression that folks suggest not greasing a carbon seat post because it can make the post too slick, causing it to slip more easily, further leading to someone over-tightening the clamp and crushing the post.

How does greasing the post lead to it being stuck?

cudak888 

https://www.google.com/search?hl=en&q...=Google+Search

-Kurt

Stallionforce

Thanks guys. I've put some penetrant down it and I'll see if I can get it loose tomorrow. If not I guess I'll have to take it back to the LBS and maybe they can hack it off and pry out the shards and I can put in a new seat post. Oh well.

sherbornpeddler

S Force,
So what happened?
I found your June discussion with interest (one guess why) and am interested in how it "worked out".

My situation
I've a Serrotta Fierte with carbon back stay bonded to the steel frame just south of the seat tube. Yes, FSA seat post stuck in the steel frame. I'm concerned about PB penetraiting oil as it might weaken the carbon back stay to seat tube bond.

Looks like a 1" reamer or drill would remove 50% of the seat post and annoy the remaining bit. If the about 15cm of the post is in the seat tube, the rest is on the shoop floor after it broke off flush to the top of the seat tube.

sherbornpeddler

FYI, I hack sawed and peeled and yanked bits and pieces out. I removed the part that had stuck to the inside diameter of the seat tube. It turns out the seat tube is double butted with the top 3" or so smaller diameter than the remaining part. The last 1 or 2" of the carbon seat post fell down teh tube. The frayed end prevents any hope of pulling it out so after an eventfull replacement with a good old (cheaper) (lubricated) aluminum seatpost I rode to NH. Guess what? It rattles like a broken water bottle cage.

I am dreaming of forceps and a long nosed nibbler to get the carbon rattler out of there.

henria86

Just disasemble the whole bike an use compressed air to blow out the bits of carbon.. an for the rest of it use a alloy tube with alot of lube to tap out the rest of the bits..

operator

The only thing your link helps you prove is that Jive was 100% right. Now that there are products that were designed specifically with carbon posts/AL seattubes in mind there is no longer any reason NOT to use said products.

sherbornpeddler

My Fierte is steel seat tube but the same holds true. BTW, The remaining rattling bit is a full cylinder with a splayed end so at this point it can't be blown out. I did have the bottom bracket out for the first operation where the stuck portion was removed. With very long nose plier-vice grips maybe I can nibble and fray the rest into small, removable pieces. I am wondering what to use to cut and nibble the remaining piece. It can't get closer than the 3 or 4 inches of the top of the seat tube.

alcanoe

There is a special paste for carbon seat posts inserted into aluminum tubes. Apparently, the carbon bonds somewhat to the aluminum and you can run into that problem. I don't know about steel, but it'd be worth investigating with a google search.

HillRider

You can get the stub out of the bottom of the seat tube, assuming the seat tube is open at the bottom bracket end.

Remove the bottom bracket and take a saber saw with a long fine tooth blade and place the blade through the bb shell with the teeth pointing up. Use the saw to slit and slice sections off of the seat post stub and break it out on smaller pieces.

Do this outside or with a lot of ventilation and use a "dust mask" while sawing.

sherbornpeddler

Great idea Hillrider and thanks for the dust caution. Sadly, my Fierte only has a weep hole, not a slot. Got long handled nibbler anyone?

damocles1

Okay, I've done this TOO many times...

Cut the post off about 1/2" to 1" above the seat clamp.
Take the hacksaw out of the saw and wrap one end in a towel.
Use this modified blade to cut the post by putting the blade down into the carbon tube.
Make vertical cuts MOST of the way through the post at even intervals around the tube.
-4 or 5 cuts does the trick
Once you've made all of the cuts, take a set a Channel Lock type pliers and crush the seatpost carefully.
The crushing will break the post free and you can pull it out.

This works EVERY TIME!!!!

nitropowered

I would have clamped the seatpost in a bench vice and used the frame to twist the sp out of the frame.

Panthers007

Carbon in a vice would likely shatter into deadly, sharp shards. You can shatter it just tightening it. I often wonder why people buy seatposts made of carbon - myself included!

Do let us know what happens. We're probably next.

sherbornpeddler

my carbon seat post cracked then snapped immediately at the top of the seat tube clamp so no chance to use a vice. My careful sawing led to pry and peel and successful removal. It left the bottom frayed portion. I did install an Al post but the left over piece in the seat tube rattles about just above the bottom bracket.

Sci-Fi

Most say don't use grease, BUT FSA sells a Carbon Fiber Assembly Compound and even started to include a packet of the stuff with all their carbon fiber seat posts. In Europe, Tacx Carbon Assembly Compound/Tacx Dynamic Carbon Assembly Paste may be easier to find and is the same stuff as FSA and is also sold in the States. Scott Carbon Grease is another option.

In any case, it's basically a non-metallic anti-seize compound.

sherbornpeddler

Sci Fi
I wonder what the chemical reaction is between the steel frame and clear epoxy of the outer surface of the seat post (carbon fiber is buried in the epoxy).

Sci-Fi

^read the last 2 comments (carbon seatpost stuck in steel seat tube):
https://www.velonews.com/article/9023

It appears the reason 'no grease' is advocated is to lessen the chance of overtightening as if it was greased and had slippage (some have slippage even if there was no grease/lube present and torqued to the recommended setting..usually around 8 Nm) and crushing the carbon fiber which may lead to catastrophic failure and an emergency visit to the proctologist. You are going to get an argument either way - to grease or not - but almost all carbon seatpost manufacturers recommend removing the seatpost periodically, more frequently if you live in high humidity/wet and/or salt/near the ocean conditions.

Personally, if you aren't racing and don't need to save weight, stick to metal seatposts and/or use fiberglass sleeves or even paper as a barrier between dis-similar metals/alloys or carbon fiber materials if you are adament about not using grease/CF assembly paste/anti-seize/etc.

sherbornpeddler

Thanks very much for your research. I still wonder chemically what happened.

Yep, I'm with you SciFi and back to Aluminum, grease and...a rattling left over piece of carbon. My LBS suggests laying the frame sideways and securing it (well below the replacement post) with a dab of epoxy. I still am dreaming of a long nosed nibbler.

Panthers007

Or just pack the seatpost with grease - and see if it dissolves!

MadeInItaly

Someone put a carbon post in a Master XL. Dumb Putts... Please don't do the same..

HillRider

You can get a spray can of "foam in place" insulation used to insulate inaccessable areas by putting a thin nozzle through any small gap and the foam expands to fill the space. A squirt of this through the vent in the bottom of your seat tube above the bb shell should secure the stub in place and stop the rattle.

joejack951

I'd try something like these to hold the piece of post: https://www.thetoolwarehouse.net/shop/SK-17851.html and then something like this: https://hand-tools.hardwarestore.com/...aw-600282.aspx to cut through the leftover post. In a completely different but somewhat related scenario, I used a combination like the above to saw through and collapse a piece of tailpipe that I knocked into the catalytic converter of one of my old cars.