Hi folks,
I need help – I have a 2000s Cannondale MTB that I have been slowly renovating. Now was the time to swap the seat post, but it seems this has been stuck for ages.
I have tried penetrating oil, rust removal soak, using the bike as leverage in wise and now even heating up the frame – nothing has worked.
I managed to slightly hammer it downwards and a tiny bit of twisting, but no big advancements yet.
What do I do? No bike shop wants to help after explaining what I tried, and they do not have any of the fancy hydraulic rigs I see around.
Any tips?
Frame is aluminum.
TIA
by malthevj
16 Comments
Hit YouTube.Â
Heat, WD40, and more bashing
A machine shop can certainly mill it out, or you can attempt to do that job yourself by using hacksaw blades to cut away, [like this](https://www.youtube.com/watch?v=wzAeSUf-90w).
The fact that the seatpost moved down means that it’s not entirely stuck. If I saw even a hint of movement, I’d be standing on top of the bench vise with the bike upside down, wrenching that thing back and forth. If it’s moving, I think it’ll eventually budge.
spray some wd 40 on it and bash the top from an angle with a mallet
[The Sheldon Brown Site: 16 ways to Unstick a Seatpost](https://www.sheldonbrown.com/stuck-seatposts.html)
Put the seatpost in vise with bike upsidedown off course ,yank the vise really thight and twist the frame Back and forth and while doing that give also fource upwards and it will get loose!
Try cutting the seatpost off flush with the frame and then carefully sawing a slit inside the post to relieve tension. It’s a last resort but can work when nothing else does.
A big pipe wrench get it twisting around and around use a big pipe wrench
What did you heat it with? Some try with heat guns but that might not be enough. Gas torch can make a difference, but is very likely to ruin the paint.
Worst case you can saw it off and mount a smaller diameter post in it. It looks pretty wide so a smaller one should fit within.
[How much Force do you need to Pull out a Stuck Seatpost?](https://www.youtube.com/watch?v=tVXgnqm2qEs)
You are very likely at the “cut the seatpost” stage [https://youtu.be/qwiwxuzyXoo?t=1024](https://youtu.be/qwiwxuzyXoo?t=1024)
I don’t know. Looking at the photo, there looks to be damage and corrosion under the paint on the seat stay wishbone. With that damage and the damage to the post from trying to remove it, you may be out of luck.
For others reading this: never ever drive a seatpost down to attempt to loosen it. It is quite literally like trying to remove a nail by driving it further into the wood. Only twisting or upwards movements are allowed.
Also it is unfortunate you have destroyed the saddle clamp. A saddle can be an excellent lever for twisting actions on the post. If I can get a post to twist just the smallest amount by whacking the saddle (and with penetrating oil soaking in) I get the post out every time.
I think your best hope now is to engineer a slide hammer you can somehow attach to that post head.
I’m also kinda worried with what’s happening on your seatstay
Had the same problem with a vintage road bike from the 50s wd40 grip the seatpost as hard as possible wiggle and twist it at the same time as hard as humanly possible that worked on it after 20mins of contemplating if it was really worth it…
Get a new bike? !