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26 comments
I’ve got a carbon post stuck in a steel frame. I really carefully claned and degreased before i put the post in with a coating of assembly paste. However it’s jammed and needs to come out. Anybody got any ideas. Please.
Gentle heat ie. no more than a hair dryer on the seat tube for a few minutes followed by a bit of gentle twist. Repeat until complete.
If it doesn't work you can try soaking in WD-40/GT85/Plusgas overnight and then trying the above again.
Bear in mind that if you're twisting the post using the saddle, the clamp bond will not fare well unless it releases with minimal effort... so don't give it major Welly unless the post is going to be binned.
I had the Ti Frame / Alloy seet post problems a few years back I'm amazed it happened so fast. All I can recommend is what worked for me and fit old saddle that you're not concerned about and liberal applying wd40 and twist, leave over night and come back to it. I think it took me two or three days. I now have a carbon post and used carbomn paste and touch wood every time I've come back to itI've never had a problem with that.
I usually had good success by taking out the bolts from the bottle cage on the seat tube and blasting loads of WD40 through the hole and leaving the frame upside down overnight. Then take off the saddle mount from the seatpost if it can be removed, put the head of the seatpost into a bench vice and use the frame as the lever by grasping the head tube and chain stays and rotate and work the frame back and forth and lift it up as you work it. The seatpost may well have to die in order to get a good clamp in the vice, I usually managed to save about 75% of them.
As said above, once out, use anti-seize compound on the frame and post to reassemble, and take it out and clean it up a couple of times a year as part of your maintenance schedule.
When you do eventually succeed in removing the old post and if you replace it with another ally post consider using this stuff:
http://www.mbfg.co.uk/bonding-structural-adhesives/duralac.html
It is used on aircraft assemblies to prevent galvanic corrosion.
A slide hammer will be very effective. Ive used them on motorcycle swingarm linkages which had completely rusted together. It took an hour, mm by mm the rusted linkage slid out.
If all else fails then there's a YouTube video on removing a stuck seatpost by cutting it down and cutting slots in it. The video shows it better than I explained it.
Last resort
Plus Gas?
And leave in a warm room?
Linear thermal expansion per ℃ is about 2.5 times less with titanium compared to aluminium.
Therefore getting the seat post cold would assist clearance.
http://qsmart.net.au/sample-post/penetrene-2/
This is the oil I was taught too use. Not sure if your British, Yankee, Kiwi, etc but a penetrating oil left to soak down overnight in a cold dry store might help. Then twist and pull.
When out, if part is serviceable, drowning in white vinegar overnight eats away at the corrosion . A pretty efficient cleaner.
That's the stuff 'tache. It has a few more things in it than copper slip. Titaniumis a bugger for sticking to other metals, especially to itself. I think that's why Park and a few other companies have come up with improved versions of copper slip.
Pilot Pete, I use normal grease like that on most seatposts but if I had a titanium bike I'd use an improved version of copper slip like the Park stuff.
Not sure about Jterrier but I was referring specifically to Park's ASC-1, Anti-Seize Compound, similar to the copper stuff but a little more gunmetal rather than coppery.
I've done a few and the seat post was toast before I started.... freeze spray, penetrating oil...patience and a slide hammer is often needed.....if it twists.... it'll come out... sometimes a slide hammer pulling it out a bit.... then clears the "sticking" point ...
Can I just clarify here because we all use different terminologies. I'm sure 'tache and jterrier are referring to anti-seize (aka copper slip etc), not carbon assembly paste.
Maybe, but maybe not. Maybe they are referring to something like this -
https://www.tredz.co.uk/.Morgan-Blue-Aquaproof-Paste_62822.htm
+1 for the assembly paste.
Turn her upside down and fill her with penetrating fluid. Soak for longer than you really want to, clamp the post, it's probably dead anyway and then move the frame, good luck.
Finish line freeze spray. Then use assembly paste in future to avoid galvanic corrosion.
If it will turn it will come out.
Gets some more penetrating oil into it as it's turning and work it round. Dont be scared about using to much as youll need to clean everything up anyway. If you're lucky, you might get it out after just a few (many) minutes.
If not, soak it for another couple of days and then GENTLY twist it out in a spiral motion using the frame to make the movement. If you have a vice to grip the saddle or post, great. Otherwise jam it some other way.
Remember not to push/pull on the rear dropouts unless they are braced eg. by an old hub and do not use any more than gentle pressure... Otherwise... You'll be buying a new frame.
Thanks all. Lennard Zinn suggests ammonia to chemicaly reduce the corrosion. For some reason I'm have a little trepidation about it. Heating and cooling and soaking in WD40 has got us to a seat post that will turn, but is still really stiff
Foot between the downtube and seat tube, hold the seat and pull :-).... Don't try this with a carbon frame...
A 120 kg, 2.0 metre friend who is a former internatioal rugby prop was doign that bit, but it still wouldn't come, so I turned away from the brawn of NZ, and consluted the brains of road.cc
good god, my phone's inability to auto correct is nearly as embarrassing as my retarded inputs. I hope none of road.cc's brains were hurt in the conslutation process
Use heat on the titanium frame to try and expand the metal a little. Heat and cooling could help break the corrosion. Once post is free and out clean seat tube internals. Remove BB or work with frame upside down. Use a brush handle wrapped in a medium grit emery paper to clean away surface damage. Apply thin layer of grease inside seat post but not on the first inch, this will help prevent corrosion but also allow enough grip to hold seat post in position. Take bike apart more often also works
theseatpostman.com
If you feel you can do no more
This. I think he uses voodoo, but have a look at his photos and you will be converted. There is one where the post was sheared off at the head, with only broken crozzle sticking out of the seat tube. Next shot is a clean as a whistle seat tube.
I paid him recently to remove an aluminium seatpost from a very new steel frame. His method is a trade secret but he had it out no problems, cost me £70. The frame is worth about £1800, so it is a small price to pay. He gave me the top half of the seatpost back, but the bottom half was gone - so I think he probably machines them out, very carefully, on a specially-built jig. Fair play to him, he's very good at his job.
I did a load of research after this, trying to find the best product to use to prevent future seizure. I went through boating forums (many pastes are sold to prevent all manner of issues on the seas), but could find no agreement. The best solution, I think, is just to use a common old grease and check the post every few months to make sure it still slides smoothly. If there's ever a hint of stiffness, even just a little bit, remove the post and clean it up. It only takes a small amount of corrosion to get it stuck in there.
Agree with Boatsie. Buy a can of proper penetrating oil and hose it from both ends for a few days (spray down the seat tube from the bottom bracket shell as well). Would then also help to heat the seat tube with a hair drier to expand the titanium and carefully twist it out. Good luck!
Oil. Patience.