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Carbon Fiber seatpost- stuck!

Old 01-28-21, 08:09 AM
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Tandem Tom
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Carbon Fiber seatpost- stuck!

So I have a cf frame that is in need of a new seatpost. All the misc parts are missing. But it is good and firmly stuck in the seat tube.
Two questions. What is the best way to remove it? And do I have to use a cf seatpost or can I use an aluminum one?
Thanks!
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Old 01-28-21, 08:54 AM
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Ok. To clarify, you have a CF frame and a CF seatpost, and the seatpost won't move after you've removed the seatpost clamp?

As for replacement suggestions, that really depends on the frame. Older Trek OCLV frames used a fiberglass sleeve in the seat tube to provide a galvanic barrier for aluminum posts, but using fibergrip or other CF and aluminum assembly paste is a great idea to prevent slipping, corrosion, and sticking.
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Old 01-28-21, 09:01 AM
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Once the post is removed any post that fits the frame (as in diameter and/or shape) could be used. The examples of a brand/model specific post requirement is more about shape or fastening method then that of material. Using a post whose material has the same electro/chemical reactive nature as the frame is one way to reduce the galvanic sourced corrosion. Carbon and Al are rather different on that scale. I wonder if the person who assembled the bike was following the "don't use lube on carbon" that some believe in, and the post was inserted dry of any protective film (grease or carbon assembly paste).

Do you know how deep the post is in the seat tube? Given that carbon is fairly easily sawed with a hack saw blade (compared to Al) I would be tempted to use a saw blade held in a jab saw handle. If the saw blade can reach the end of the post (cutting off the post just above the frame helps the reach) this will take far less time then if the post were Al. There's a lot of stuck seat post threads here although most of then are about Al posts in steel frames, so the chemical methods might not transfer over to the carbon post in Al frame the OP has. Andy
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Old 01-28-21, 09:11 AM
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Originally Posted by Andrew R Stewart View Post
Once the post is removed any post that fits the frame (as in diameter and/or shape) could be used. The examples of a brand/model specific post requirement is more about shape or fastening method then that of material. Using a post whose material has the same electro/chemical reactive nature as the frame is one way to reduce the galvanic sourced corrosion. Carbon and Al are rather different on that scale. I wonder if the person who assembled the bike was following the "don't use lube on carbon" that some believe in, and the post was inserted dry of any protective film (grease or carbon assembly paste).

Do you know how deep the post is in the seat tube? Given that carbon is fairly easily sawed with a hack saw blade (compared to Al) I would be tempted to use a saw blade held in a jab saw handle. If the saw blade can reach the end of the post (cutting off the post just above the frame helps the reach) this will take far less time then if the post were Al. There's a lot of stuck seat post threads here although most of then are about Al posts in steel frames, so the chemical methods might not transfer over to the carbon post in Al frame the OP has. Andy
Just a caution: Park Tool advises against trying to cut out a stuck carbon post. Personally, I'm certain I won't feel a transition between the post and the frame using a jab saw.

I googled it and GCN has a recommendation:
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Old 01-28-21, 09:13 AM
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Originally Posted by Unca_Sam View Post
Just a caution: Park Tool advises against trying to cut out a stuck carbon post. Personally, I'm certain I won't feel a transition between the post and the frame using a jab saw.

I googled it and GCN has a recommendation:https://youtu.be/54WhdrLKKvY
And if the frame were made of carbon I agree completely. But the OP has an Al frame. Andy
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Old 01-28-21, 10:40 AM
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Andy,
I kinda like your idea but the frame is cf. I am tempted to put a pipe wrench to the stuck seatpost.
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Old 01-28-21, 10:44 AM
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?

watch the posted video-some very good tips.and boiling water is free,no? note when its out use a long stick to smear grease down inside the seatpost tube.patience is key.
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Old 01-28-21, 10:59 AM
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YA! Using the GCN method and some patience, you might be able to save the seatpost, to install properly later.

Is it possible the wrong size post was used?

Edit: probably not. Using a hammer to install a seatpost is a good indicator something is wrong.
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Old 01-28-21, 12:49 PM
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Bench vise and my incredible strength 😁😁😁. I won!!!
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Old 01-28-21, 01:13 PM
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Originally Posted by Tandem Tom View Post
Bench vise and my incredible strength 😁😁😁. I won!!!
Now check any parts, the seat stay and bb/chain stay junction, that could have suffered torque during the fight.
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Old 01-28-21, 05:30 PM
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I had this happen and used a rust degreaser (blast I believe) and knocked it loose with a rubber mallet. Try moving left and right. It took a few rounds, maybe a day or two, and lots of sweat. I couldn't get the seat post back in so I cut it down and used carbon paste to prevent it from happening again. Its good to take the seat out and move it around every few months or so.
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Old 01-28-21, 06:39 PM
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Originally Posted by Tandem Tom View Post
Andy,
I kinda like your idea but the frame is cf. I am tempted to put a pipe wrench to the stuck seatpost.
Once again I am at fault for not reading the OP as well as I should, as Rozana Dana Dana (or whoever that Laugh In character was) said, "never mind" Andy
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Old 01-29-21, 02:51 AM
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Roseanne Roseannadanna, Saturday Night Live.
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Old 01-29-21, 06:52 AM
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Originally Posted by flanso View Post
Roseanne Roseannadanna, Saturday Night Live.
These lucid dreaming posts are a fascinating look at the subconscious.
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Old 01-30-21, 07:37 AM
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