Seat post stuck and just won't budge.....

[Ange_Andrews]

I'm thinking about buying a second-hand Giant Advanced TCR 2 (2013) off a friend who recently upgraded to something shinier and newer.

However, I need to raise the seat-post a little, and even though I've unloosened the bolts completely, the seat post simply won't budge - it is stuck tight in place. I can't wiggle the seat laterally (like when removing the cork from a champagne bottle), as the seat post is tear-drop shaped (not round). I've done some extensive googling on-line, but most of the advice is conflicting, so I reckon I'd be better off taking it to a LBS, rather than mucking around with it myself and breaking anything by using too much brute force.

As far as I can work out from trying to make sense of the specs online, it's a carbon composite frame (Advanced-Grade Composite) and carbon composite seat-post (Giant Vector Composite), but TBH, I've been riding the same old workhorse for over 15 years, and am not really techie, so I'm not sure if I've understood the lingo correctly. In the meantime, I'm gonna follow some advice I read online which is to loosen the seat post bolts completely, and take it for a short, bumpy ride to see if my bodyweight might be enough to jolt the seat post and get it unstuck. Eeek!! Wish me luck!!

However, what I'm really after is a recommendation for a Melbs LBS mechanic that has expertise and experience in addressing this specific issue, without causing damage. This is especially important, as the bike still belongs to my friend, and if I can't adjust the seat post, then I won't be buying the bike....

Thanks in advance for any advice and recommendations.

[Duck!]

Give the post a good whack front & rear and under the saddle with a rubber mallet, a bit of shock usually does the trick.

Do NOT loosen the clamp and go for a ride. If it slips and hits the wheel cutaway, or it's already bottomed out, there is a very high possibility of splitting the frame!

[Tim]

In the meantime, I'm gonna follow some advice I read online which is to loosen the seat post bolts completely, and take it for a short, bumpy ride to see if my bodyweight might be enough to jolt the seat post and get it unstuck. Eeek!! Wish me luck!!

I wouldn't do that.
If the joint lets go all of a sudden you risk damaging the bottom of the seat post or worse still cracking the frame seat tube where it narrows down.
I specifically remember reading of someone that cracked the same frame along the seat tube from inserting the seatpost too far into the frame.
I'd just try soaking with something like Penetrene or even WD40.

edit; Duck beat me off the mark.( He's a pretty good bike mechanic from all accounts. Based in Melb too.)

[open roader]

I had the 2010 TCR Adv model. Same deal, same aero profile seatpost. The seat post would not lift after 9 months. I used a block of soft pine under the saddle and tapped it out with a hammer - didn't take too much hammer effort, just enough to break the jam.

I then cleaned up the seat post and inside the seat tube and applied carbon assembly paste - my mate now rides that frame, 8 years later with no issue.

I'd echo the sentiments above - if that seatpost is crammed too far down into the seat tube it can damage the frame where the rear wheel cutout is - seen this too.............

[Tamiya]

At least with Plastic on Plastic, unlike steel you're lucky it won't be jammed in by rust

[Ange_Andrews]

Thank you so much to everyone who’s responded so far. I’ll start by giving the old seat a beating with a rubber mallet and let you know how if I have any luck.... Fingers crossed!

[stevenaaus]

Lots of threads here about stuck seatposts, but i'll just revive this one.

Picked up a 2008 Fuji team pro frame cheap. It's a carbon post in carbon frame, no rotation or movement, and a nasty 2cm hairline crack beneath post cutaway slot... but there's a chance it's paint only.

So.... started to give it some hammer taps and soak with silicon spray. I'll see how it goes.
But Sheldon advises against "oil" as it expands the tube... hmmm.
https://www.sheldonbrown.com/stuck-seatposts.html

Pretty annoyed that the fork also has a top crush *&^%!# after seller said fork was fine, so might need to take 7mm off it too. B****y useless home mechanics, laugh. But at thirty bucks, it's still a cheap wall decoration.

[oxonabike]

You might be able to whip up something similar to what this bloke did....

[stevenaaus]

Yeah ^^^^ That's pretty impressive.

But i got it! Halleluihah. I'd pumped a bit of silicon spray into the tube, i didn't want to leave it forever as i'm on holiday at the coast.

So , grabbed a right-angle wheel-jack lever from the car and slipped it through the saddle rails, giving me a bit more leaverage. Now i could twist it back and forth (while leaning the frame against my seat) without busting my back as i did yesterday. Small movements finally got it out.

And the paint crack is nowhere to be seen on the carbon inside. Yay. But b****y Fuji, the "C4" branded carbon seatpost is 1.5mm alloy with a super thin carbon wrap, laugh. No wonder there's so much oxidisation in there. Lovely coast weather oxidises everything.

[bychosis]

My recent seatpost 'fun' was resolved by drilling two holes in a decent thickness steel plate and bolting it to the seatpost. Then clamped the steel to a verandah post. The used a ratchet strap around the bottom bracket area to another nearby post and tensioned it up. Once tensioned I was able to use the frame as leverage to rotate around the seatpost.it gave an almighty crack and broke free.

I'd been using WD40 to soak, a mallet to shock it, hot water and had only been able to twist the seatpost a bit in place (same height). Holding it under tension while twisting was the key.

[elantra]

……..
And the paint crack is nowhere to be seen on the carbon inside. Yay. But b****y Fuji, the "C4" branded carbon seatpost is 1.5mm alloy with a super thin carbon wrap, laugh. No wonder there's so much oxidisation in there. Lovely coast weather oxidises everything.

Crikeys you can learn something new every day on this forum.
I honestly didn’t know that (some) carbon fibre seatposts are not really carbon fibre at all - they are aluminium with an outer layer of carbon fibre.

I think I have heard of some handlebars made this way and I spose that some stems might also be done this way.

I spose it’s one solution to the potential problem of aluminium getting badly corroded if it is in direct contact (and not isolated by lubricants etc) with carbon fibre.

Not long ago I was given a frame in poor condition (Columbus SL steel tubing) with a stuck seatpost.

seatpost (chrome steel in this case) was not the original seatpost but it was the correct diameter.
In this case, after the usual huffing and puffing and spraying of WD40 got me nowhere - so I used power drill to put 8mm diameter hole right through the seatpost.
Then I put a rather large solid metal Tentpeg right into the hole and slightly out the other side.
This did the trick.
The tentpeg was just long enough and tough enough to act as a rotational lever assisted by a few hammer taps and the bond was broken and the seatpost was removed fairly easily but obviously not in a fit condition to be used again.

[stevenaaus]

Yeah, I was trying to not bust the "C4" seatpost, so was pretty disappointed when I incredulously started to scrape away the muck and saw the heavy POS thing.

https://m.youtube.com/shorts/nJ2VWQBtOhQ
https://m.youtube.com/shorts/Zjp3VR0Uylw
https://m.youtube.com/shorts/n9OQykeuHzA
https://m.youtube.com/shorts/NC3CqlVTPSU