CapKong

My aero aluminum seatpost is currently stuck in my aluminum seatpost. What can I do to get it out? I can't push it around to get it to loose since it's aero, all I can do is pull it out. Also, I'm about to get a carbon seatpost, so what can I use to make sure that my carbon seatpost isn't going to get stuck in my aluminum frame? I heard that using fibergrip and anti-sieze is bad for aluminum and grease is bad for carbon. What should I use?

GP

Soak it with penetrating oil then use a rubber mallet and to tap down on the saddle. When it breaks loose tap the bottom of the saddle nose up.

CapKong

Alright, thanks. That'ls what I'll try. What do you recommend I use for my carbon seatpost on aluminum frame? Fiber grip? Anti-seize? Grease?

FBinNY 

Aluminum/aluminum combinations aren't as prone to issues as when dissimilar metals are used , ie. aluminum post in steel frame. Not being able to rotate it does make it tougher. Faced with a situation where I can't pull a post out, I usually use "reverse psychology" on it and try to push it in a bit more. Of course it has nothing to do with psychology, but it is far easier to drive a post in than pull it out. Tis also gives me a decent sense of how stuck it actually is.

To use this technique, remove the saddle and support the BB shell on something like a wooden block, so it can't move and diffuse any energy that way. Protect the top of the post with another piece of wood, and deliver a solid blow with a hammer. If the post isn't truly frozen, it'll move and you'll know that it can and will come out if persuaded properly.

Once you've shown that it can move, the best method is to clamp an old junk saddle into the post, and try tapping it up from underneath. Bracing the frame and/or hammering directly on the post also help, but aren't that easy on most posts. Soaking in penetrating oil for 24 hours before trying also helps, and on some bikes this works better if the BB is removed, and oil is poured into the inverted seat tube through the BB shell.

If the post doesn't move when you try driving it inward, you're in for a tough fight. Sometimes a long soak in penetrating oil, like Kroil or PB Blaster helps as does ammonia. But IME ammonia only does any good if it's the first thing used, since any oil will prevent it from getting to where it needs to be.

One other last resort method that sometimes works is to securely clamp the post in a heavy vice on a solid workbench, and hammer the frame down off it. This is a tricky process and requires that you find a place to hammer on the frame that won't damage it. Or you might try bracing a jack of some kind between the crank or BB and the underside of the saddle and sacking it up slowly.

Whatever you decide, I still find that driving it in is a good diagnostic tool which will tell you what you're dealing with.

Fastfingaz

First make sure that its the correct Size,

CapKong

Thanks! I'm going to get penetration oil first thing in the morning tomorrow.

CapKong

Yes, it is the correct size. It is the only carbon seatpost made specifically for my frame.

FBinNY 

We need to clarify something which makes a world of difference.

In your OP you described both the post and frame as being of aluminum (I assumed a typo and figured you meant post in seat tube). Now you say a CF post. If either is CF and the other aluminum, that's vastly different than a like material situation. Aluminum and CF together are very prone to galvanic corrosion, and if they've been together a while and/or subjected to wet weather riding, you're in for a long tough battle.

Certainly go ahead and do the in first test to see if it moves, but if not, expect to have to get the post out destructively. The aero shape will call for lots of hand work, and be forewarned that CF in aluminum is a more difficult situation than the reverse.

Miele Man

Do you have a CO2 tire inflator and cartridge?

Spray the CO@ onto the seatpost above the frame and the rapid cooling might just shrink it enough to become small enough to come out easily by pulling on the saddle. If you have someone pulling up on the nose and rear of the saddle whilst you spray the CO2 onto the seatpost near the top of the frame you may experience the seatpost comming out VERY suddenly.

Try not to spray the CO2 onto the seat tube.

Cheers

bykemike 

Kong,

How long has it been in there? Do you live in a coastal town (ocean that is)?

FB sez "you're in for a tough fight" and that may be so true. I have had to remove one with a reciprocating saw, it wasn't pretty but it was that or look for another bike.

Try all the easy ways first, of course, and good luck with it.

Looigi

One thing I've done to get a bit better grip on things and apply more force is to turn the bike upside down so I can step on the the front and rear of the saddle with my toes and pull up on the frame. Be appropriately wary of sharp chain ring teeth. You can do something similar reclining with the bike on top of you, drive side up.

dedhed

OP states AL "post" in AL "post" which I think the second should have said "tube". He is removing it to install a carbon one.

CapKong

Yes, in my OP I state that currently it is a alu seatpost and seattube that is stuck. I'm trying to take it off so i can replace it with a caron seatpoat and I want to know what I can do to ake sure my carbon seatpost isnt going to be stuck in my alu frame.

FBinNY 

You can use a non-abrasive carbon assembly paste, which has soft high friction particles plus (usually) anti-seize material in a grease base that is compatible with the clear coat on the post. You need less traction than average since the post cannot twist, and will be fine if/when the current post is out.

OldTryGuy

Hair dryer on seat tube to warm and expand seat tube.

curbtender

I've never seen a carbon seat post get frozen. My concern would be damage to the seat tube causing scoring that would transfer to your new post.

bykemike 

When carbon seizes to carbon, well, now you have a fight on you hands

CapKong

Thanks guys! It's out now. I am going to replace my alu seatpost with the carbon seatpost now. So I should put non-abrasive carbon assembly paste on my alu seat tube and carbon seatpost? You all recommend to put this stuff on?

FBinNY 

NOW, I'm insulted!!!!.

Not really, but you'll never get anything close to universal agreement on anything you might ask on BF.

But I can tell you that dry mounting may lead to galvanic corrosion, greasing to prevent that, may lead to slippage. Both are may, not will, but the possibilities are real enough. So an anti-seize/traction compound of one type or another, is the only way to address one problem without making the other worse.

CapKong

Lol, sorry just want to make sure that it's safe to use. But I'm gonna trust you and use it since you're quite popular here.

Miele Man

So, just how did you get it out?

Cheers

dedhed

I think you'll get nearly universal agreement on this.